// ***************************************************************************************************************************
// * Licensed to the Apache Software Foundation (ASF) under one or more contributor license agreements.  See the NOTICE file *
// * distributed with this work for additional information regarding copyright ownership.  The ASF licenses this file        *
// * to you under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance            *
// * with the License.  You may obtain a copy of the License at                                                              *
// *                                                                                                                         *
// *  http://www.apache.org/licenses/LICENSE-2.0                                                                             *
// *                                                                                                                         *
// * Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an  *
// * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  See the License for the        *
// * specific language governing permissions and limitations under the License.                                              *
// ***************************************************************************************************************************
package org.apache.juneau.rest.client2;

import static org.apache.juneau.internal.StringUtils.*;
import static org.apache.juneau.internal.ClassUtils.*;
import static org.apache.juneau.AddFlag.*;
import static org.apache.juneau.httppart.HttpPartType.*;

import java.io.*;
import java.lang.reflect.*;
import java.net.*;
import java.text.*;
import java.util.*;
import java.util.concurrent.*;
import java.util.function.*;
import java.util.logging.*;

import org.apache.http.*;
import org.apache.http.client.config.*;
import org.apache.http.client.entity.*;
import org.apache.http.client.methods.*;
import org.apache.http.client.utils.*;
import org.apache.http.concurrent.*;
import org.apache.http.entity.*;
import org.apache.http.entity.BasicHttpEntity;
import org.apache.http.entity.ContentType;
import org.apache.http.params.*;
import org.apache.http.protocol.*;
import org.apache.juneau.*;
import org.apache.juneau.collections.*;
import org.apache.juneau.html.*;
import org.apache.juneau.http.*;
import org.apache.juneau.http.header.*;
import org.apache.juneau.httppart.*;
import org.apache.juneau.internal.*;
import org.apache.juneau.json.*;
import org.apache.juneau.msgpack.*;
import org.apache.juneau.oapi.*;
import org.apache.juneau.parser.*;
import org.apache.juneau.plaintext.*;
import org.apache.juneau.serializer.*;
import org.apache.juneau.uon.*;
import org.apache.juneau.urlencoding.*;
import org.apache.juneau.xml.*;

/**
 * Represents a request to a remote REST resource.
 *
 * <p>
 * Instances of this class are created by the various creator methods on the {@link RestClient} class.
 *
 * <ul class='seealso'>
 *    <li class='jc'>{@link RestClient}
 *    <li class='link'>{@doc juneau-rest-client}
 * </ul>
 */
public class RestRequest extends BeanSession implements HttpUriRequest, Configurable {

   private static final ContentType TEXT_PLAIN = ContentType.create("text/plain");

   private final RestClient client;                       // The client that created this call.
   private final HttpRequestBase request;                 // The request.
   private RestResponse response;                         // The response.
   List<RestCallInterceptor> interceptors = new ArrayList<>();   // Used for intercepting and altering requests.

   private boolean ignoreErrors;

   private Object input;
   private boolean hasInput;                              // input() was called, even if it's setting 'null'.
   private Serializer serializer;
   private Parser parser;
   private HttpPartSerializerSession partSerializer;
   private HttpPartSchema requestBodySchema;
   private URIBuilder uriBuilder;
   private List<NameValuePair> formData;
   private Predicate<Integer> errorCodes;
   private HttpHost target;
   private HttpContext context;

   /**
    * Constructs a REST call with the specified method name.
    *
    * @param client The client that created this request.
    * @param uri The target URI.
    * @param method The HTTP method name (uppercase).
    * @param hasBody Whether this method has a body.
    * @throws RestCallException If an exception or non-200 response code occurred during the connection attempt.
    */
   protected RestRequest(RestClient client, URI uri, String method, boolean hasBody) throws RestCallException {
      super(client, BeanSessionArgs.DEFAULT);
      this.client = client;
      this.request = createInnerRequest(method, uri, hasBody);
      this.errorCodes = client.errorCodes;
      this.partSerializer = client.getPartSerializerSession();
      this.uriBuilder = new URIBuilder(request.getURI());
      this.ignoreErrors = client.ignoreErrors;
   }

   /**
    * Constructs the {@link HttpRequestBase} object that ends up being passed to the client execute method.
    *
    * <p>
    * Subclasses can override this method to create their own request base objects.
    *
    * @param method The HTTP method.
    * @param uri The HTTP URI.
    * @param hasBody Whether the HTTP request has a body.
    * @return A new {@link HttpRequestBase} object.
    */
   protected HttpRequestBase createInnerRequest(String method, URI uri, boolean hasBody) {
      HttpRequestBase req = hasBody ? new BasicHttpEntityRequestBase(this, method) : new BasicHttpRequestBase(this, method);
      req.setURI(uri);
      return req;
   }


   //------------------------------------------------------------------------------------------------------------------
   // Configuration
   //------------------------------------------------------------------------------------------------------------------

   /**
    * Convenience method for specifying JSON as the marshalling transmission media type for this request only.
    *
    * <p>
    * {@link JsonSerializer} will be used to serialize POJOs to request bodies unless overridden per request via {@link RestRequest#serializer(Serializer)}.
    *    <ul>
    *       <li>The serializer can be configured using any of the serializer property setters (e.g. {@link RestClientBuilder#sortCollections()}),
    *          bean context property setters (e.g. {@link RestClientBuilder#swaps(Object...)}), or generic property setters (e.g. {@link RestClientBuilder#set(String, Object)}) defined on this builder class.
    *    </ul>
    * <p>
    *    {@link JsonParser} will be used to parse POJOs from response bodies unless overridden per request via {@link RestRequest#parser(Parser)}.
    *    <ul>
    *       <li>The parser can be configured using any of the parser property setters (e.g. {@link RestClientBuilder#strict()}),
    *          bean context property setters (e.g. {@link RestClientBuilder#swaps(Object...)}), or generic property setters (e.g. {@link RestClientBuilder#set(String, Object)}) defined on this builder class.
    *    </ul>
    * <p>
    *    <c>Accept</c> request header will be set to <js>"application/json"</js> unless overridden
    *       by {@link RestRequest#header(String,Object)} or {@link RestRequest#accept(Object)}.
    * <p>
    *    <c>Content-Type</c> request header will be set to <js>"application/json"</js> unless overridden
    *       {@link RestRequest#header(String,Object)} or {@link RestRequest#contentType(Object)}.
    * <p>
    *    Identical to calling <c>serializer(JsonSerializer.<jk>class</jk>).parser(JsonParser.<jk>class</jk>)</c>.
    *
    * @return This object (for method chaining).
    */
   public RestRequest json() {
      return serializer(JsonSerializer.class).parser(JsonParser.class);
   }

   /**
    * Convenience method for specifying Simplified JSON as the marshalling transmission media type for this request only.
    *
    * <p>
    * Simplified JSON is typically useful for automated tests because you can do simple string comparison of results
    * without having to escape lots of quotes.
    *
    * <p>
    *    {@link SimpleJsonSerializer} will be used to serialize POJOs to request bodies unless overridden per request via {@link RestRequest#serializer(Serializer)}.
    *    <ul>
    *       <li>The serializer can be configured using any of the serializer property setters (e.g. {@link RestClientBuilder#sortCollections()}),
    *          bean context property setters (e.g. {@link RestClientBuilder#swaps(Object...)}), or generic property setters (e.g. {@link RestClientBuilder#set(String, Object)}) defined on this builder class.
    *    </ul>
    * <p>
    *    {@link JsonParser} will be used to parse POJOs from response bodies unless overridden per request via {@link RestRequest#parser(Parser)}.
    *    <ul>
    *       <li>The parser can be configured using any of the parser property setters (e.g. {@link RestClientBuilder#strict()}),
    *          bean context property setters (e.g. {@link RestClientBuilder#swaps(Object...)}), or generic property setters (e.g. {@link RestClientBuilder#set(String, Object)}) defined on this builder class.
    *    </ul>
    * <p>
    *    <c>Accept</c> request header will be set to <js>"application/json"</js> unless overridden
    *       by {@link #header(String,Object)} or {@link #accept(Object)}, or per-request via {@link RestRequest#header(String,Object)} or {@link RestRequest#accept(Object)}.
    * <p>
    *    <c>Content-Type</c> request header will be set to <js>"application/json+simple"</js> unless overridden
    *       by {@link #header(String,Object)} or {@link #contentType(Object)}, or per-request via {@link RestRequest#header(String,Object)} or {@link RestRequest#contentType(Object)}.
    * <p>
    *    Can be combined with other marshaller setters such as {@link #xml()} to provide support for multiple languages.
    *    <ul>
    *       <li>When multiple languages are supported, the <c>Accept</c> and <c>Content-Type</c> headers control which marshallers are used, or uses the
    *       last-enabled language if the headers are not set.
    *    </ul>
    * <p>
    *    Identical to calling <c>serializer(SimpleJsonSerializer.<jk>class</jk>).parser(JsonParser.<jk>class</jk>)</c>.
    *
    * <h5 class='section'>Example:</h5>
    * <p class='bcode w800'>
    *    <jc>// Construct a client that uses Simplified JSON marshalling.</jc>
    *    RestClient <jv>client</jv> = RestClient.<jsm>create</jsm>().simpleJson().build();
    * </p>
    *
    * @return This object (for method chaining).
    */
   public RestRequest simpleJson() {
      return serializer(SimpleJsonSerializer.class).parser(SimpleJsonParser.class);
   }

   /**
    * Convenience method for specifying XML as the marshalling transmission media type for this request only.
    *
    * <p>
    * {@link XmlSerializer} will be used to serialize POJOs to request bodies unless overridden per request via {@link RestRequest#serializer(Serializer)}.
    *    <ul>
    *       <li>The serializer can be configured using any of the serializer property setters (e.g. {@link RestClientBuilder#sortCollections()}),
    *          bean context property setters (e.g. {@link RestClientBuilder#swaps(Object...)}), or generic property setters (e.g. {@link RestClientBuilder#set(String, Object)}) defined on this builder class.
    *    </ul>
    * <p>
    *    {@link XmlParser} will be used to parse POJOs from response bodies unless overridden per request via {@link RestRequest#parser(Parser)}.
    *    <ul>
    *       <li>The parser can be configured using any of the parser property setters (e.g. {@link RestClientBuilder#strict()}),
    *          bean context property setters (e.g. {@link RestClientBuilder#swaps(Object...)}), or generic property setters (e.g. {@link RestClientBuilder#set(String, Object)}) defined on this builder class.
    *    </ul>
    * <p>
    *    <c>Accept</c> request header will be set to <js>"text/xml"</js> unless overridden
    *       by {@link RestRequest#header(String,Object)} or {@link RestRequest#accept(Object)}.
    * <p>
    *    <c>Content-Type</c> request header will be set to <js>"text/xml"</js> unless overridden
    *       by {@link RestRequest#header(String,Object)} or {@link RestRequest#contentType(Object)}.
    * <p>
    *    Identical to calling <c>serializer(XmlSerializer.<jk>class</jk>).parser(XmlParser.<jk>class</jk>)</c>.
    *
    * <h5 class='section'>Example:</h5>
    * <p class='bcode w800'>
    *    <jc>// Construct a client that uses XML marshalling.</jc>
    *    RestClient <jv>client</jv> = RestClient.<jsm>create</jsm>().xml().build();
    * </p>
    *
    * @return This object (for method chaining).
    */
   public RestRequest xml() {
      return serializer(XmlSerializer.class).parser(XmlParser.class);
   }

   /**
    * Convenience method for specifying HTML as the marshalling transmission media type for this request only.
    *
    * <p>
    * POJOs are converted to HTML without any sort of doc wrappers.
    *
    * <p>
    *    {@link HtmlSerializer} will be used to serialize POJOs to request bodies unless overridden per request via {@link RestRequest#serializer(Serializer)}.
    *    <ul>
    *       <li>The serializer can be configured using any of the serializer property setters (e.g. {@link RestClientBuilder#sortCollections()}),
    *          bean context property setters (e.g. {@link RestClientBuilder#swaps(Object...)}), or generic property setters (e.g. {@link RestClientBuilder#set(String, Object)}) defined on this builder class.
    *    </ul>
    * <p>
    *    {@link HtmlParser} will be used to parse POJOs from response bodies unless overridden per request via {@link RestRequest#parser(Parser)}.
    *    <ul>
    *       <li>The parser can be configured using any of the parser property setters (e.g. {@link RestClientBuilder#strict()}),
    *          bean context property setters (e.g. {@link RestClientBuilder#swaps(Object...)}), or generic property setters (e.g. {@link RestClientBuilder#set(String, Object)}) defined on this builder class.
    *    </ul>
    * <p>
    *    <c>Accept</c> request header will be set to <js>"text/html"</js> unless overridden
    *       by {@link RestRequest#header(String,Object)} or {@link RestRequest#accept(Object)}.
    * <p>
    *    <c>Content-Type</c> request header will be set to <js>"text/html"</js> unless overridden
    *       by {@link RestRequest#header(String,Object)} or {@link RestRequest#contentType(Object)}.
    * <p>
    *    Identical to calling <c>serializer(HtmlSerializer.<jk>class</jk>).parser(HtmlParser.<jk>class</jk>)</c>.
    *
    * <h5 class='section'>Example:</h5>
    * <p class='bcode w800'>
    *    <jc>// Construct a client that uses HTML marshalling.</jc>
    *    RestClient <jv>client</jv> = RestClient.<jsm>create</jsm>().html().build();
    * </p>
    *
    * @return This object (for method chaining).
    */
   public RestRequest html() {
      return serializer(HtmlSerializer.class).parser(HtmlParser.class);
   }

   /**
    * Convenience method for specifying HTML DOC as the marshalling transmission media type for this request only.
    *
    * <p>
    * POJOs are converted to fully renderable HTML pages.
    *
    * <p>
    *    {@link HtmlDocSerializer} will be used to serialize POJOs to request bodies unless overridden per request via {@link RestRequest#serializer(Serializer)}.
    *    <ul>
    *       <li>The serializer can be configured using any of the serializer property setters (e.g. {@link RestClientBuilder#sortCollections()}),
    *          bean context property setters (e.g. {@link RestClientBuilder#swaps(Object...)}), or generic property setters (e.g. {@link RestClientBuilder#set(String, Object)}) defined on this builder class.
    *    </ul>
    * <p>
    *    {@link HtmlParser} will be used to parse POJOs from response bodies unless overridden per request via {@link RestRequest#parser(Parser)}.
    *    <ul>
    *       <li>The parser can be configured using any of the parser property setters (e.g. {@link RestClientBuilder#strict()}),
    *          bean context property setters (e.g. {@link RestClientBuilder#swaps(Object...)}), or generic property setters (e.g. {@link RestClientBuilder#set(String, Object)}) defined on this builder class.
    *    </ul>
    * <p>
    *    <c>Accept</c> request header will be set to <js>"text/html"</js> unless overridden
    *       by {@link RestRequest#header(String,Object)} or {@link RestRequest#accept(Object)}.
    * <p>
    *    <c>Content-Type</c> request header will be set to <js>"text/html"</js> unless overridden
    *       by {@link RestRequest#header(String,Object)} or {@link RestRequest#contentType(Object)}.
    * <p>
    *    Identical to calling <c>serializer(HtmlDocSerializer.<jk>class</jk>).parser(HtmlParser.<jk>class</jk>)</c>.
    *
    * <h5 class='section'>Example:</h5>
    * <p class='bcode w800'>
    *    <jc>// Construct a client that uses HTML Doc marshalling.</jc>
    *    RestClient <jv>client</jv> = RestClient.<jsm>create</jsm>().htmlDoc().build();
    * </p>
    *
    * @return This object (for method chaining).
    */
   public RestRequest htmlDoc() {
      return serializer(HtmlDocSerializer.class).parser(HtmlParser.class);
   }

   /**
    * Convenience method for specifying Stripped HTML DOC as the marshalling transmission media type for this request only.
    *
    * <p>
    * Same as {@link #htmlDoc()} but without the header and body tags and page title and description.
    *
    * <p>
    *    {@link HtmlStrippedDocSerializer} will be used to serialize POJOs to request bodies unless overridden per request via {@link RestRequest#serializer(Serializer)}.
    *    <ul>
    *       <li>The serializer can be configured using any of the serializer property setters (e.g. {@link RestClientBuilder#sortCollections()}),
    *          bean context property setters (e.g. {@link RestClientBuilder#swaps(Object...)}), or generic property setters (e.g. {@link RestClientBuilder#set(String, Object)}) defined on this builder class.
    *    </ul>
    * <p>
    *    {@link HtmlParser} will be used to parse POJOs from response bodies unless overridden per request via {@link RestRequest#parser(Parser)}.
    *    <ul>
    *       <li>The parser can be configured using any of the parser property setters (e.g. {@link RestClientBuilder#strict()}),
    *          bean context property setters (e.g. {@link RestClientBuilder#swaps(Object...)}), or generic property setters (e.g. {@link RestClientBuilder#set(String, Object)}) defined on this builder class.
    *    </ul>
    * <p>
    *    <c>Accept</c> request header will be set to <js>"text/html+stripped"</js> unless overridden
    *       by {@link RestRequest#header(String,Object)} or {@link RestRequest#accept(Object)}.
    * <p>
    *    <c>Content-Type</c> request header will be set to <js>"text/html+stripped"</js> unless overridden
    *       by {@link RestRequest#header(String,Object)} or {@link RestRequest#contentType(Object)}.
    * <p>
    *    Identical to calling <c>serializer(HtmlStrippedDocSerializer.<jk>class</jk>).parser(HtmlParser.<jk>class</jk>)</c>.
    *
    * <h5 class='section'>Example:</h5>
    * <p class='bcode w800'>
    *    <jc>// Construct a client that uses HTML Stripped Doc marshalling.</jc>
    *    RestClient <jv>client</jv> = RestClient.<jsm>create</jsm>().htmlStrippedDoc().build();
    * </p>
    *
    * @return This object (for method chaining).
    */
   public RestRequest htmlStrippedDoc() {
      return serializer(HtmlStrippedDocSerializer.class).parser(HtmlParser.class);
   }

   /**
    * Convenience method for specifying Plain Text as the marshalling transmission media type for this request only.
    *
    * <p>
    * Plain text marshalling typically only works on simple POJOs that can be converted to and from strings using
    * swaps, swap methods, etc...
    *
    * <p>
    *    {@link PlainTextSerializer} will be used to serialize POJOs to request bodies unless overridden per request via {@link RestRequest#serializer(Serializer)}.
    *    <ul>
    *       <li>The serializer can be configured using any of the serializer property setters (e.g. {@link RestClientBuilder#sortCollections()}),
    *          bean context property setters (e.g. {@link RestClientBuilder#swaps(Object...)}), or generic property setters (e.g. {@link RestClientBuilder#set(String, Object)}) defined on this builder class.
    *    </ul>
    * <p>
    *    {@link PlainTextParser} will be used to parse POJOs from response bodies unless overridden per request via {@link RestRequest#parser(Parser)}.
    *    <ul>
    *       <li>The parser can be configured using any of the parser property setters (e.g. {@link RestClientBuilder#strict()}),
    *          bean context property setters (e.g. {@link RestClientBuilder#swaps(Object...)}), or generic property setters (e.g. {@link RestClientBuilder#set(String, Object)}) defined on this builder class.
    *    </ul>
    * <p>
    *    <c>Accept</c> request header will be set to <js>"text/plain"</js> unless overridden
    *       by {@link RestRequest#header(String,Object)} or {@link RestRequest#accept(Object)}.
    * <p>
    *    <c>Content-Type</c> request header will be set to <js>"text/plain"</js> unless overridden
    *       by {@link RestRequest#header(String,Object)} or {@link RestRequest#contentType(Object)}.
    * <p>
    *    Identical to calling <c>serializer(PlainTextSerializer.<jk>class</jk>).parser(PlainTextParser.<jk>class</jk>)</c>.
    *
    * <h5 class='section'>Example:</h5>
    * <p class='bcode w800'>
    *    <jc>// Construct a client that uses Plain Text marshalling.</jc>
    *    RestClient <jv>client</jv> = RestClient.<jsm>create</jsm>().plainText().build();
    * </p>
    *
    * @return This object (for method chaining).
    */
   public RestRequest plainText() {
      return serializer(PlainTextSerializer.class).parser(PlainTextParser.class);
   }

   /**
    * Convenience method for specifying MessagePack as the marshalling transmission media type for this request only.
    *
    * <p>
    * MessagePack is a binary equivalent to JSON that takes up considerably less space than JSON.
    *
    * <p>
    *    {@link MsgPackSerializer} will be used to serialize POJOs to request bodies unless overridden per request via {@link RestRequest#serializer(Serializer)}.
    *    <ul>
    *       <li>The serializer can be configured using any of the serializer property setters (e.g. {@link RestClientBuilder#sortCollections()}),
    *          bean context property setters (e.g. {@link RestClientBuilder#swaps(Object...)}), or generic property setters (e.g. {@link RestClientBuilder#set(String, Object)}) defined on this builder class.
    *    </ul>
    * <p>
    *    {@link MsgPackParser} will be used to parse POJOs from response bodies unless overridden per request via {@link RestRequest#parser(Parser)}.
    *    <ul>
    *       <li>The parser can be configured using any of the parser property setters (e.g. {@link RestClientBuilder#strict()}),
    *          bean context property setters (e.g. {@link RestClientBuilder#swaps(Object...)}), or generic property setters (e.g. {@link RestClientBuilder#set(String, Object)}) defined on this builder class.
    *    </ul>
    * <p>
    *    <c>Accept</c> request header will be set to <js>"octal/msgpack"</js> unless overridden
    *       by {@link RestRequest#header(String,Object)} or {@link RestRequest#accept(Object)}.
    * <p>
    *    <c>Content-Type</c> request header will be set to <js>"octal/msgpack"</js> unless overridden
    *       by {@link RestRequest#header(String,Object)} or {@link RestRequest#contentType(Object)}.
    * <p>
    *    Identical to calling <c>serializer(MsgPackSerializer.<jk>class</jk>).parser(MsgPackParser.<jk>class</jk>)</c>.
    *
    * <h5 class='section'>Example:</h5>
    * <p class='bcode w800'>
    *    <jc>// Construct a client that uses MessagePack marshalling.</jc>
    *    RestClient <jv>client</jv> = RestClient.<jsm>create</jsm>().msgPack().build();
    * </p>
    *
    * @return This object (for method chaining).
    */
   public RestRequest msgPack() {
      return serializer(MsgPackSerializer.class).parser(MsgPackParser.class);
   }

   /**
    * Convenience method for specifying UON as the marshalling transmission media type for this request only.
    *
    * <p>
    * UON is Url-Encoding Object notation that is equivalent to JSON but suitable for transmission as URL-encoded
    * query and form post values.
    *
    * <p>
    *    {@link UonSerializer} will be used to serialize POJOs to request bodies unless overridden per request via {@link RestRequest#serializer(Serializer)}.
    *    <ul>
    *       <li>The serializer can be configured using any of the serializer property setters (e.g. {@link RestClientBuilder#sortCollections()}),
    *          bean context property setters (e.g. {@link RestClientBuilder#swaps(Object...)}), or generic property setters (e.g. {@link RestClientBuilder#set(String, Object)}) defined on this builder class.
    *    </ul>
    * <p>
    *    {@link UonParser} will be used to parse POJOs from response bodies unless overridden per request via {@link RestRequest#parser(Parser)}.
    *    <ul>
    *       <li>The parser can be configured using any of the parser property setters (e.g. {@link RestClientBuilder#strict()}),
    *          bean context property setters (e.g. {@link RestClientBuilder#swaps(Object...)}), or generic property setters (e.g. {@link RestClientBuilder#set(String, Object)}) defined on this builder class.
    *    </ul>
    * <p>
    *    <c>Accept</c> request header will be set to <js>"text/uon"</js> unless overridden
    *       by {@link RestRequest#header(String,Object)} or {@link RestRequest#accept(Object)}.
    * <p>
    *    <c>Content-Type</c> request header will be set to <js>"text/uon"</js> unless overridden
    *       by {@link RestRequest#header(String,Object)} or {@link RestRequest#contentType(Object)}.
    * <p>
    *    Identical to calling <c>serializer(UonSerializer.<jk>class</jk>).parser(UonParser.<jk>class</jk>)</c>.
    *
    * <h5 class='section'>Example:</h5>
    * <p class='bcode w800'>
    *    <jc>// Construct a client that uses UON marshalling.</jc>
    *    RestClient <jv>client</jv> = RestClient.<jsm>create</jsm>().uon().build();
    * </p>
    *
    * @return This object (for method chaining).
    */
   public RestRequest uon() {
      return serializer(UonSerializer.class).parser(UonParser.class);
   }

   /**
    * Convenience method for specifying URL-Encoding as the marshalling transmission media type for this request only.
    *
    * <p>
    *    {@link UrlEncodingSerializer} will be used to serialize POJOs to request bodies unless overridden per request via {@link RestRequest#serializer(Serializer)}.
    *    <ul>
    *       <li>The serializer can be configured using any of the serializer property setters (e.g. {@link RestClientBuilder#sortCollections()}),
    *          bean context property setters (e.g. {@link RestClientBuilder#swaps(Object...)}), or generic property setters (e.g. {@link RestClientBuilder#set(String, Object)}) defined on this builder class.
    *       <li>This serializer is NOT used when using the {@link RestRequest#formData(String, Object)} (and related) methods for constructing
    *          the request body.  Instead, the part serializer specified via {@link RestClientBuilder#partSerializer(Class)} is used.
    *    </ul>
    * <p>
    *    {@link UrlEncodingParser} will be used to parse POJOs from response bodies unless overridden per request via {@link RestRequest#parser(Parser)}.
    *    <ul>
    *       <li>The parser can be configured using any of the parser property setters (e.g. {@link RestClientBuilder#strict()}),
    *          bean context property setters (e.g. {@link RestClientBuilder#swaps(Object...)}), or generic property setters (e.g. {@link RestClientBuilder#set(String, Object)}) defined on this builder class.
    *    </ul>
    * <p>
    *    <c>Accept</c> request header will be set to <js>"application/x-www-form-urlencoded"</js> unless overridden
    *       by {@link RestRequest#header(String,Object)} or {@link RestRequest#accept(Object)}.
    * <p>
    *    <c>Content-Type</c> request header will be set to <js>"application/x-www-form-urlencoded"</js> unless overridden
    *       by {@link RestRequest#header(String,Object)} or {@link RestRequest#contentType(Object)}.
    * <p>
    *    Identical to calling <c>serializer(UrlEncodingSerializer.<jk>class</jk>).parser(UrlEncodingParser.<jk>class</jk>)</c>.
    *
    * <h5 class='section'>Example:</h5>
    * <p class='bcode w800'>
    *    <jc>// Construct a client that uses URL-Encoded marshalling.</jc>
    *    RestClient <jv>client</jv> = RestClient.<jsm>create</jsm>().urlEnc().build();
    * </p>
    *
    * @return This object (for method chaining).
    */
   public RestRequest urlEnc() {
      return serializer(UrlEncodingSerializer.class).parser(UrlEncodingParser.class);
   }

   /**
    * Convenience method for specifying OpenAPI as the marshalling transmission media type for this request only.
    *
    * <p>
    * OpenAPI is a language that allows serialization to formats that use {@link HttpPartSchema} objects to describe their structure.
    *
    * <p>
    *    {@link OpenApiSerializer} will be used to serialize POJOs to request bodies unless overridden per request via {@link RestRequest#serializer(Serializer)}.
    *    <ul>
    *       <li>The serializer can be configured using any of the serializer property setters (e.g. {@link RestClientBuilder#sortCollections()}),
    *          bean context property setters (e.g. {@link RestClientBuilder#swaps(Object...)}), or generic property setters (e.g. {@link RestClientBuilder#set(String, Object)}) defined on this builder class.
    *       <li>Typically the {@link RestRequest#body(Object, HttpPartSchema)} method will be used to specify the body of the request with the
    *          schema describing it's structure.
    *    </ul>
    * <p>
    *    {@link OpenApiParser} will be used to parse POJOs from response bodies unless overridden per request via {@link RestRequest#parser(Parser)}.
    *    <ul>
    *       <li>The parser can be configured using any of the parser property setters (e.g. {@link RestClientBuilder#strict()}),
    *          bean context property setters (e.g. {@link RestClientBuilder#swaps(Object...)}), or generic property setters (e.g. {@link RestClientBuilder#set(String, Object)}) defined on this builder class.
    *       <li>Typically the {@link RestResponseBody#schema(HttpPartSchema)} method will be used to specify the structure of the response body.
    *    </ul>
    * <p>
    *    <c>Accept</c> request header will be set to <js>"text/openapi"</js> unless overridden
    *       by {@link RestRequest#header(String,Object)} or {@link RestRequest#accept(Object)}.
    * <p>
    *    <c>Content-Type</c> request header will be set to <js>"text/openapi"</js> unless overridden
    *       by {@link RestRequest#header(String,Object)} or {@link RestRequest#contentType(Object)}.
    * <p>
    *    Identical to calling <c>serializer(OpenApiSerializer.<jk>class</jk>).parser(OpenApiParser.<jk>class</jk>)</c>.
    *
    * <h5 class='section'>Example:</h5>
    * <p class='bcode w800'>
    *    <jc>// Construct a client that uses OpenAPI marshalling.</jc>
    *    RestClient <jv>client</jv> = RestClient.<jsm>create</jsm>().openApi().build();
    * </p>
    *
    * @return This object (for method chaining).
    */
   public RestRequest openApi() {
      return serializer(OpenApiSerializer.class).parser(OpenApiParser.class);
   }

   /**
    * Specifies the serializer to use on the request body.
    *
    * <p>
    * Overrides the serializers specified on the {@link RestClient}.
    *
    * <p>
    *    The serializer is not modified by an of the serializer property setters (e.g. {@link RestClientBuilder#sortCollections()}),
    *    bean context property setters (e.g. {@link RestClientBuilder#swaps(Object...)}), or generic property setters (e.g. {@link RestClientBuilder#set(String, Object)}) defined on this builder class.
    *
    * <p>
    * If the <c>Content-Type</c> header is not set on the request, it will be set to the media type of this serializer.
    *
    * @param serializer The serializer used to serialize POJOs to the body of the HTTP request.
    * @return This object (for method chaining).
    */
   public RestRequest serializer(Serializer serializer) {
      this.serializer = serializer;
      return this;
   }

   /**
    * Specifies the serializer to use on the request body.
    *
    * <p>
    * Overrides the serializers specified on the {@link RestClient}.
    *
    * <p>
    *    The serializer can be configured using any of the serializer property setters (e.g. {@link RestClientBuilder#sortCollections()}),
    *    bean context property setters (e.g. {@link RestClientBuilder#swaps(Object...)}), or generic property setters (e.g. {@link RestClientBuilder#set(String, Object)}) defined on this builder class.
    *
    * <p>
    * If the <c>Content-Type</c> header is not set on the request, it will be set to the media type of this serializer.
    *
    * @param serializer The serializer used to serialize POJOs to the body of the HTTP request.
    * @return This object (for method chaining).
    */
   public RestRequest serializer(Class<? extends Serializer> serializer) {
      this.serializer = client.getInstance(serializer);
      return this;
   }

   /**
    * Specifies the parser to use on the response body.
    *
    * <p>
    * Overrides the parsers specified on the {@link RestClient}.
    *
    * <p>
    *    The parser is not modified by any of the parser property setters (e.g. {@link RestClientBuilder#strict()}),
    *    bean context property setters (e.g. {@link RestClientBuilder#swaps(Object...)}), or generic property setters (e.g. {@link RestClientBuilder#set(String, Object)}) defined on this builder class.
    *
    * <p>
    * If the <c>Accept</c> header is not set on the request, it will be set to the media type of this parser.
    *
    * @param parser The parser used to parse POJOs from the body of the HTTP response.
    * @return This object (for method chaining).
    */
   public RestRequest parser(Parser parser) {
      this.parser = parser;
      return this;
   }

   /**
    * Specifies the parser to use on the response body.
    *
    * <p>
    * Overrides the parsers specified on the {@link RestClient}.
    *
    * <p>
    *    The parser can be configured using any of the parser property setters (e.g. {@link RestClientBuilder#strict()}),
    *    bean context property setters (e.g. {@link RestClientBuilder#swaps(Object...)}), or generic property setters (e.g. {@link RestClientBuilder#set(String, Object)}) defined on this builder class.
    *
    * <p>
    * If the <c>Accept</c> header is not set on the request, it will be set to the media type of this parser.
    *
    * @param parser The parser used to parse POJOs from the body of the HTTP response.
    * @return This object (for method chaining).
    */
   public RestRequest parser(Class<? extends Parser> parser) {
      this.parser = client.getInstance(parser);
      return this;
   }

   /**
    * Allows you to override what status codes are considered error codes that would result in a {@link RestCallException}.
    *
    * <p>
    * The default error code predicate is: <code>x -&gt; x &gt;= 400</code>.
    *
    * @param value The new predicate for calculating error codes.
    * @return This object (for method chaining).
    */
   public RestRequest errorCodes(Predicate<Integer> value) {
      this.errorCodes = value;
      return this;
   }

   /**
    * Add one or more interceptors for this call only.
    *
    * @param interceptors The interceptors to add to this call.
    * @return This object (for method chaining).
    * @throws RestCallException If init method on interceptor threw an exception.
    */
   public RestRequest interceptors(RestCallInterceptor...interceptors) throws RestCallException {
      try {
         for (RestCallInterceptor i : interceptors) {
            this.interceptors.add(i);
            i.onInit(this);
         }
      } catch (RuntimeException | RestCallException e) {
         throw e;
      } catch (Exception e) {
         throw new RestCallException(null, e, "Interceptor threw an exception on init.");
      }

      return this;
   }

   /**
    * Prevent {@link RestCallException RestCallExceptions} from being thrown when HTTP status 400+ is encountered.
    *
    * <p>
    * This overrides the <l>ignoreErrors</l> property on the client.
    *
    * @return This object (for method chaining).
    */
   public RestRequest ignoreErrors() {
      this.ignoreErrors = true;
      return this;
   }

   /**
    * Sets <c>Debug: value</c> header on this request.
    *
    * @return This object (for method chaining).
    * @throws RestCallException Invalid input.
    */
   public RestRequest debug() throws RestCallException {
      header("Debug", true);
      return this;
   }

   /**
    * Returns <jk>true</jk> if debug mode is currently enabled.
    */
   @Override
   public boolean isDebug() {
      return getHeader("Debug", "false").equalsIgnoreCase("true");
   }

   /**
    * Specifies the target host for the request.
    *
    * @param target The target host for the request.
    *    Implementations may accept <jk>null</jk> if they can still determine a route, for example to a default
    *    target or by inspecting the request.
    * @return This object (for method chaining).
    */
   public RestRequest target(HttpHost target) {
      this.target = target;
      return this;
   }

   /**
    * Override the context to use for the execution.
    *
    * @param context The context to use for the execution, or <jk>null</jk> to use the default context.
    * @return This object (for method chaining).
    */
   public RestRequest context(HttpContext context) {
      this.context = context;
      return this;
   }

   //------------------------------------------------------------------------------------------------------------------
   // URI
   //------------------------------------------------------------------------------------------------------------------

   /**
    * Sets the URI for this request.
    *
    * <p>
    * Can be any of the following types:
    * <ul>
    *    <li>{@link URI}
    *    <li>{@link URL}
    *    <li>{@link URIBuilder}
    *    <li>Anything else converted to a string using {@link Object#toString()}.
    * </ul>
    *
    * <p>
    * Relative URI strings will be interpreted as relative to the root URI defined on the client.
    *
    * @param uri
    *    The URI of the remote REST resource.
    *    <br>This overrides the URI passed in from the client.
    *    <br>Can be any of the following types:
    *    <ul>
    *       <li>{@link URIBuilder}
    *       <li>{@link URI}
    *       <li>{@link URL}
    *       <li>{@link String}
    *       <li>{@link Object} - Converted to <c>String</c> using <c>toString()</c>
    *    </ul>
    * @return This object (for method chaining).
    * @throws RestCallException Invalid URI syntax detected.
    */
   public RestRequest uri(Object uri) throws RestCallException {
      URI x = client.toURI(uri, null);
      if (x.getScheme() != null)
         uriBuilder.setScheme(x.getScheme());
      if (x.getHost() != null)
         uriBuilder.setHost(x.getHost());
      if (x.getPort() != -1)
         uriBuilder.setPort(x.getPort());
      if (x.getUserInfo() != null)
         uriBuilder.setUserInfo(x.getUserInfo());
      if (x.getFragment() != null)
         uriBuilder.setFragment(x.getFragment());
      if (x.getQuery() != null)
         uriBuilder.setCustomQuery(x.getQuery());
      uriBuilder.setPath(x.getPath());
      return this;
   }

   /**
    * Sets the URI scheme.
    *
    * @param scheme The new URI host.
    * @return This object (for method chaining).
    */
   public RestRequest scheme(String scheme) {
      uriBuilder.setScheme(scheme);
      return this;
   }

   /**
    * Sets the URI host.
    *
    * @param host The new URI host.
    * @return This object (for method chaining).
    */
   public RestRequest host(String host) {
      uriBuilder.setHost(host);
      return this;
   }

   /**
    * Sets the URI port.
    *
    * @param port The new URI port.
    * @return This object (for method chaining).
    */
   public RestRequest port(int port) {
      uriBuilder.setPort(port);
      return this;
   }

   /**
    * Sets the URI user info.
    *
    * @param userInfo The new URI user info.
    * @return This object (for method chaining).
    */
   public RestRequest userInfo(String userInfo) {
      uriBuilder.setUserInfo(userInfo);
      return this;
   }

   /**
    * Sets the URI user info.
    *
    * @param username The new URI username.
    * @param password The new URI password.
    * @return This object (for method chaining).
    */
   public RestRequest userInfo(String username, String password) {
      uriBuilder.setUserInfo(username, password);
      return this;
   }

   /**
    * Sets the URI fragment.
    *
    * @param fragment The URI fragment.  The value is expected to be unescaped and may contain non ASCII characters.
    * @return This object (for method chaining).
    */
   public RestRequest fragment(String fragment) {
      uriBuilder.setFragment(fragment);
      return this;
   }

   //------------------------------------------------------------------------------------------------------------------
   // Path
   //------------------------------------------------------------------------------------------------------------------

   /**
    * Replaces a path parameter of the form <js>"{name}"</js> in the URI.
    *
    * <h5 class='section'>Example:</h5>
    * <p class='bcode w800'>
    *    <jc>// Sets path to "/bar".</jc>
    *    <jv>client</jv>
    *       .get(<js>"/{foo}"</js>)
    *       .path(<js>"foo"</js>, <js>"bar"</js>)
    *       .run();
    * </p>
    *
    * @param name The parameter name.
    * @param value The parameter value.
    *    <ul>
    *       <li>Value can be any POJO or POJO {@link Supplier}.
    *       <li>Value converted to a string using the configured part serializer.
    *    </ul>
    * @return This object (for method chaining).
    * @throws RestCallException Invalid input.
    */
   public RestRequest path(String name, Object value) throws RestCallException {
      return paths(serializedNameValuePair(name, value, PATH, partSerializer, null, null));
   }

   /**
    * Replaces a path parameter of the form <js>"{name}"</js> in the URI.
    *
    * <h5 class='section'>Example:</h5>
    * <p class='bcode w800'>
    *    <jc>// Sets path to "/bar".</jc>
    *    <jv>client</jv>
    *       .get(<js>"/{foo}"</js>)
    *       .path(BasicNameValuePair.<jsm>of</jsm>(<js>"foo"</js>, <js>"bar"</js>))
    *       .run();
    * </p>
    *
    * @param pair The parameter.
    * @return This object (for method chaining).
    * @throws RestCallException Invalid input.
    */
   public RestRequest path(NameValuePair pair) throws RestCallException {
      return paths(pair);
   }

   /**
    * Replaces a path parameter of the form <js>"{name}"</js> in the URI.
    *
    * <h5 class='section'>Example:</h5>
    * <p class='bcode w800'>
    *    <jc>// Sets path to "/bar|baz".</jc>
    *    <jv>client</jv>
    *       .get(<js>"/{foo}"</js>)
    *       .path(
    *          <js>"foo"</js>, AList.<jsm>of</jsm>(<js>"bar"</js>,<js>"baz"</js>),
    *          HttpPartSchema.<jsf>T_ARRAY_PIPES</jsf>
    *       )
    *       .run();
    * </p>
    *
    * @param name The parameter name.
    * @param value The parameter value.
    *    <ul>
    *       <li>Value can be any POJO or POJO {@link Supplier}.
    *       <li>Value converted to a string using the configured part serializer.
    *    </ul>
    * @param schema The part schema.  Can be <jk>null</jk>.
    * @return This object (for method chaining).
    * @throws RestCallException Invalid input.
    */
   public RestRequest path(String name, Object value, HttpPartSchema schema) throws RestCallException {
      return paths(serializedNameValuePair(name, value, PATH, partSerializer, schema, null));
   }

   /**
    * Replaces multiple path parameter of the form <js>"{name}"</js> in the URI.
    *
    * <h5 class='section'>Example:</h5>
    * <p class='bcode w800'>
    *    <jc>// Sets path to "/baz/qux".</jc>
    *    <jv>client</jv>
    *       .get(<js>"/{foo}/{bar}"</js>)
    *       .paths(
    *          BasicNameValuePair.<jsm>of</jsm>(<js>"foo"</js>, <js>"baz"</js>),
    *          AMap.<jsm>of</jsm>(<js>"bar"</js>, <js>"qux"</js>)
    *       )
    *       .run();
    * </p>
    *
    * @param params
    *    The path parameters to set.
    *    <br>Can be any of the following types:
    *    <ul>
    *       <li>{@link NameValuePair}
    *       <li>{@link NameValuePairable}
    *       <li>{@link java.util.Map.Entry}
    *       <li>{@link NameValuePairSupplier}
    *       <li>{@link Map}
    *       <ul>
    *          <li>Values can be any POJO.
    *          <li>Values converted to a string using the configured part serializer.
    *       </ul>
    *       <li>A collection or array of anything on this list.
    * </ul>
    * @return This object (for method chaining).
    * @throws RestCallException Invalid input.
    */
   @SuppressWarnings("rawtypes")
   public RestRequest paths(Object...params) throws RestCallException {
      for (Object o : params) {
         if (BasicNameValuePair.canCast(o)) {
            innerPath(BasicNameValuePair.cast(o));
         } else if (o instanceof NameValuePairSupplier) {
            for (NameValuePair p : (NameValuePairSupplier)o)
               innerPath(p);
         } else if (o instanceof Collection) {
            for (Object o2 : (Collection<?>)o)
               innerPath(BasicNameValuePair.cast(o2));
         } else if (o != null && o.getClass().isArray()) {
            for (int i = 0; i < Array.getLength(o); i++)
               innerPath(BasicNameValuePair.cast(Array.get(o, i)));
         } else if (o instanceof Map) {
            for (Map.Entry e : toMap(o).entrySet())
               innerPath(serializedNameValuePair(e.getKey(), e.getValue(), PATH, partSerializer, null, null));
         } else if (isBean(o)) {
            for (Map.Entry<String,Object> e : toBeanMap(o).entrySet())
               innerPath(serializedNameValuePair(e.getKey(), e.getValue(), PATH, partSerializer, null, null));
         } else if (o != null) {
            throw new RestCallException(null, null, "Invalid type passed to paths(): {0}", className(o));
         }
      }
      return this;
   }

   /**
    * Replaces path parameters of the form <js>"{name}"</js> in the URI using free-form key/value pairs.
    *
    * <h5 class='section'>Example:</h5>
    * <p class='bcode w800'>
    *    <jc>// Sets path to "/baz/qux".</jc>
    *    <jv>client</jv>
    *       .get(<js>"/{foo}/{bar}"</js>)
    *       .pathPairs(
    *          <js>"foo"</js>,<js>"baz"</js>,
    *          <js>"bar"</js>,<js>"qux"</js>
    *       )
    *       .run();
    * </p>
    *
    * @param pairs The path key/value pairs.
    *    <ul>
    *       <li>Values can be any POJO.
    *       <li>Values converted to a string using the configured part serializer.
    *    </ul>
    * @return This object (for method chaining).
    * @throws RestCallException Invalid input.
    */
   public RestRequest pathPairs(Object...pairs) throws RestCallException {
      if (pairs.length % 2 != 0)
         throw new RestCallException(null, null, "Odd number of parameters passed into pathPairs()");
      for (int i = 0; i < pairs.length; i+=2)
         paths(serializedNameValuePair(pairs[i], pairs[i+1], PATH, partSerializer, null, null));
      return this;
   }

   RestRequest pathArg(String name, Object value, HttpPartSchema schema, HttpPartSerializerSession serializer) throws RestCallException {
      boolean isMulti = isEmpty(name) || "*".equals(name) || value instanceof NameValuePairSupplier || isNameValuePairArray(value);

      if (! isMulti)
         return innerPath(serializedNameValuePair(name, value, PATH, serializer, schema, null));

      if (BasicNameValuePair.canCast(value)) {
         innerPath(BasicNameValuePair.cast(value));
      } else if (value instanceof NameValuePairSupplier) {
         for (Object o : (NameValuePairSupplier)value)
            innerPath(BasicNameValuePair.cast(o));
      } else if (value instanceof Collection) {
         for (Object o : (Collection<?>)value)
            innerPath(BasicNameValuePair.cast(o));
      } else if (value != null && value.getClass().isArray()) {
         for (int i = 0; i < Array.getLength(value); i++)
            innerPath(BasicNameValuePair.cast(Array.get(value, i)));
      } else if (value instanceof Map) {
         for (Map.Entry<Object,Object> p : toMap(value).entrySet())
            innerPath(serializedNameValuePair(p.getKey(), p.getValue(), PATH, serializer, schema, null));
      } else if (isBean(value)) {
         for (Map.Entry<String,Object> p : toBeanMap(value).entrySet())
            innerPath(serializedNameValuePair(p.getKey(), p.getValue(), PATH, serializer, schema, null));
      } else if (value != null) {
         throw new RestCallException(null, null, "Invalid value type for path arg ''{0}'': {1}", name, className(value));
      }
      return this;
   }

   private RestRequest innerPath(NameValuePair param) throws RestCallException {
      String path = uriBuilder.getPath();
      String name = param.getName(), value = param.getValue();
      String var = "{" + name + "}";
      if (path.indexOf(var) == -1 && ! name.equals("/*"))
         throw new RestCallException(null, null, "Path variable {"+name+"} was not found in path.");
      String p = null;
      if (name.equals("/*"))
         p = path.replaceAll("\\/\\*$", "/" + value);
      else
         p = path.replace(var, String.valueOf(value));
      uriBuilder.setPath(p);
      return this;
   }

   //------------------------------------------------------------------------------------------------------------------
   // Query
   //------------------------------------------------------------------------------------------------------------------

   /**
    * Sets a query parameter on the URI.
    *
    * <h5 class='section'>Example:</h5>
    * <p class='bcode w800'>
    *    <jc>// Adds query parameter "foo=bar|baz".</jc>
    *    <jv>client</jv>
    *       .get(<jsf>URI</jsf>)
    *       .query(
    *          <jsf>APPEND</jsf>,
    *          <js>"foo"</js>, AList.<jsm>of</jsm>(<js>"bar"</js>,<js>"baz"</js>),
    *          HttpPartSchema.<jsf>T_ARRAY_PIPES</jsf>
    *    )
    *       .run();
    * </p>
    *
    * @param flag How to add this parameter.
    *    <ul>
    *       <li>{@link AddFlag#APPEND APPEND} (default) - Append to end.
    *       <li>{@link AddFlag#PREPEND PREPEND} - Prepend to beginning.
    *       <li>{@link AddFlag#REPLACE REPLACE} - Delete any existing with same name and append to end.
    *    </ul>
    * @param name The parameter name.
    * @param value The parameter value.
    *    <ul>
    *       <li>Value can be any POJO or POJO {@link Supplier}.
    *       <li>Value converted to a string using the configured part serializer.
    *    </ul>
    * @param schema The schema object that defines the format of the output.
    *    <ul>
    *       <li>If <jk>null</jk>, defaults to {@link HttpPartSchema#DEFAULT}.
    *       <li>Only used if serializer is schema-aware (e.g. {@link OpenApiSerializer}).
    *    </ul>
    * @return This object (for method chaining).
    * @throws RestCallException Invalid input.
    */
   public RestRequest query(AddFlag flag, String name, Object value, HttpPartSchema schema) throws RestCallException {
      return queries(flag, serializedNameValuePair(name, value, QUERY, partSerializer, schema, EnumSet.of(flag)));
   }

   /**
    * Adds a query parameter to the URI.
    *
    * <h5 class='section'>Example:</h5>
    * <p class='bcode w800'>
    *    <jc>// Adds query parameter "foo=bar".</jc>
    *    <jv>client</jv>
    *       .get(<jsf>URI</jsf>)
    *       .query(<js>"foo"</js>, <js>"bar"</js>)
    *       .run();
    * </p>
    *
    * @param name The parameter name.
    * @param value The parameter value.
    *    <ul>
    *       <li>Value can be any POJO or POJO {@link Supplier}.
    *       <li>Value converted to a string using the configured part serializer.
    *    </ul>
    * @return This object (for method chaining).
    * @throws RestCallException Invalid input.
    */
   public RestRequest query(String name, Object value) throws RestCallException {
      return queries(serializedNameValuePair(name, value, QUERY, partSerializer, null, null));
   }

   /**
    * Adds a query parameter to the URI.
    *
    * <h5 class='section'>Example:</h5>
    * <p class='bcode w800'>
    *    <jc>// Adds query parameter "foo=bar".</jc>
    *    <jv>client</jv>
    *       .get(<jsf>URI</jsf>)
    *       .query(BasicNameValuePair.<jsm>of</jsm>(<js>"foo"</js>, <js>"bar"</js>))
    *       .run();
    * </p>
    *
    * @param pair The parameter.
    * @return This object (for method chaining).
    * @throws RestCallException Invalid input.
    */
   public RestRequest query(NameValuePair pair) throws RestCallException {
      return queries(pair);
   }

   /**
    * Adds a query parameter to the URI.
    *
    * <p>
    * The optional schema allows for specifying how part should be serialized (as a pipe-delimited list for example).
    *
    * <h5 class='section'>Example:</h5>
    * <p class='bcode w800'>
    *    <jc>// Creates query parameter "foo=bar|baz"</jc>
    *    <jv>client</jv>
    *       .get(<jsf>URI</jsf>)
    *       .query(
    *          <js>"foo"</js>, AList.<jsm>of</jsm>(<js>"bar"</js>,<js>"baz"</js>),
    *          HttpPartSchema.<jsf>T_ARRAY_PIPES</jsf>
    *       )
    *       .run();
    * </p>
    *
    * @param name The parameter name.
    * @param value The parameter value.
    *    <ul>
    *       <li>Value can be any POJO or POJO {@link Supplier}.
    *       <li>Value converted to a string using the configured part serializer.
    *    </ul>
    * @param schema The HTTP part schema.  Can be <jk>null</jk>.
    * @return This object (for method chaining).
    * @throws RestCallException Invalid input.
    */
   public RestRequest query(String name, Object value, HttpPartSchema schema) throws RestCallException {
      return queries(serializedNameValuePair(name, value, QUERY, partSerializer, schema, null));
   }

   /**
    * Adds a query parameter to the URI.
    *
    * <h5 class='section'>Example:</h5>
    * <p class='bcode w800'>
    *    <jc>// Adds query parameter "foo=bar".</jc>
    *    <jv>client</jv>
    *       .get(<jsf>URI</jsf>)
    *       .query(
    *          <jsf>APPEND</jsf>,
    *          <js>"foo"</js>, <js>"bar"</js>
    *    )
    *       .run();
    * </p>
    *
    * @param flag How to add this parameter.
    *    <ul>
    *       <li>{@link AddFlag#APPEND APPEND} (default) - Append to end.
    *       <li>{@link AddFlag#PREPEND PREPEND} - Prepend to beginning.
    *       <li>{@link AddFlag#REPLACE REPLACE} - Delete any existing with same name and append to end.
    *    </ul>
    * @param name The parameter name.
    * @param value The parameter value.
    *    <ul>
    *       <li>Value can be any POJO or POJO {@link Supplier}.
    *       <li>Value converted to a string using the configured part serializer.
    *    </ul>
    * @return This object (for method chaining).
    * @throws RestCallException Invalid input.
    */
   public RestRequest query(AddFlag flag, String name, Object value) throws RestCallException {
      return queries(flag, serializedNameValuePair(name, value, QUERY, partSerializer, null, EnumSet.of(flag)));
   }

   /**
    * Sets multiple parameters on the query string.
    *
    * <h5 class='section'>Example:</h5>
    * <p class='bcode w800'>
    *    <jc>// Adds query parameters "foo=bar&baz=qux".</jc>
    *    <jv>client</jv>
    *       .get(<jsf>URI</jsf>)
    *       .queries(
    *          BasicNameValuePair.<jsm>of</jsm>(<js>"foo"</js>,<js>"bar"</js>),
    *          AMap.<jsm>of</jsm>(<js>"baz"</js>,<js>"qux"</js>)
    *       )
    *       .run();
    * </p>
    *
    * @param params
    *    The parameters to set.
    *    <br>Can be any of the following types:
    *    <ul>
    *       <li>{@link NameValuePair}
    *       <li>{@link NameValuePairable}
    *       <li>{@link java.util.Map.Entry}
    *       <li>{@link NameValuePairSupplier}
    *       <li>{@link Map}
    *       <ul>
    *          <li>Values can be any POJO.
    *          <li>Values converted to a string using the configured part serializer.
    *       </ul>
    *       <li>A collection or array of anything on this list.
    * </ul>
    * @return This object (for method chaining).
    * @throws RestCallException Invalid input.
    */
   public RestRequest queries(Object...params) throws RestCallException {
      return queries(APPEND, params);
   }

   /**
    * Sets multiple parameters on the query string.
    *
    * <h5 class='section'>Example:</h5>
    * <p class='bcode w800'>
    *    <jc>// Adds query parameters "foo=bar&baz=qux".</jc>
    *    <jv>client</jv>
    *       .get(<jsf>URI</jsf>)
    *       .queries(
    *          <jsf>APPEND</jsf>,
    *          BasicNameValuePair.<jsm>of</jsm>(<js>"foo"</js>,<js>"bar"</js>),
    *          AMap.<jsm>of</jsm>(<js>"baz"</js>,<js>"qux"</js>)
    *       )
    *       .run();
    * </p>
    *
    * @param flag How to add this parameter.
    *    <ul>
    *       <li>{@link AddFlag#APPEND APPEND} (default) - Append to end.
    *       <li>{@link AddFlag#PREPEND PREPEND} - Prepend to beginning.
    *       <li>{@link AddFlag#REPLACE REPLACE} - Delete any existing with same name and append to end.
    *    </ul>
    * @param params
    *    The parameters to set.
    *    <br>Can be any of the following types:
    *    <ul>
    *       <li>{@link NameValuePair}
    *       <li>{@link NameValuePairable}
    *       <li>{@link java.util.Map.Entry}
    *       <li>{@link NameValuePairSupplier}
    *       <li>{@link Map}
    *       <ul>
    *          <li>Values can be any POJO.
    *          <li>Values converted to a string using the configured part serializer.
    *       </ul>
    *       <li>A collection or array of anything on this list.
    * </ul>
    * @return This object (for method chaining).
    * @throws RestCallException Invalid input.
    */
   public RestRequest queries(AddFlag flag, Object...params) throws RestCallException {
      List<NameValuePair> l = new ArrayList<>();
      for (Object o : params) {
         if (BasicNameValuePair.canCast(o)) {
            l.add(BasicNameValuePair.cast(o));
         } else if (o instanceof NameValuePairSupplier) {
            for (NameValuePair p : (NameValuePairSupplier)o)
               l.add(p);
         } else if (o instanceof Collection) {
            for (Object o2 : (Collection<?>)o)
               l.add(BasicNameValuePair.cast(o2));
         } else if (o != null && o.getClass().isArray()) {
            for (int i = 0; i < Array.getLength(o); i++)
               l.add(BasicNameValuePair.cast(Array.get(o, i)));
         } else if (o instanceof Map) {
            for (Map.Entry<Object,Object> e : toMap(o).entrySet())
               l.add(serializedNameValuePair(e.getKey(), e.getValue(), QUERY, partSerializer, null, EnumSet.of(flag)));
         } else if (isBean(o)) {
            for (Map.Entry<String,Object> e : toBeanMap(o).entrySet())
               l.add(serializedNameValuePair(e.getKey(), e.getValue(), QUERY, partSerializer, null, EnumSet.of(flag)));
         } else if (o != null) {
            throw new RestCallException(null, null, "Invalid type passed to queries(): {0}", className(o));
         }
      }
      return innerQuery(EnumSet.of(flag), l);
   }

   /**
    * Adds query parameters to the URI query using free-form key/value pairs..
    *
    * <h5 class='section'>Example:</h5>
    * <p class='bcode w800'>
    *    <jc>// Adds query parameters "foo=bar&baz=qux".</jc>
    *    <jv>client</jv>
    *       .get(<jsf>URI</jsf>)
    *       .queryPairs(<js>"foo"</js>,<js>"bar"</js>,<js>"baz"</js>,<js>"qux"</js>)
    *       .run();
    * </p>
    *
    * @param pairs The query key/value pairs.
    *    <ul>
    *       <li>Values can be any POJO.
    *       <li>Values converted to a string using the configured part serializer.
    *    </ul>
    * @return This object (for method chaining).
    * @throws RestCallException Invalid input.
    */
   public RestRequest queryPairs(Object...pairs) throws RestCallException {
      if (pairs.length % 2 != 0)
         throw new RestCallException(null, null, "Odd number of parameters passed into queryPairs()");
      for (int i = 0; i < pairs.length; i+=2)
         queries(serializedNameValuePair(pairs[i], pairs[i+1], QUERY, partSerializer, null, null));
      return this;
   }

   /**
    * Adds a free-form custom query.
    *
    * <h5 class='section'>Example:</h5>
    * <p class='bcode w800'>
    *    <jc>// Adds query parameter "foo=bar&baz=qux".</jc>
    *    <jv>client</jv>
    *       .get(<jsf>URI</jsf>)
    *       .queryCustom(<js>"foo=bar&baz=qux"</js>)
    *       .run();
    * </p>
    *
    * @param value The parameter value.
    *    <br>Can be any of the following types:
    *    <ul>
    *       <li>
    *          {@link CharSequence}
    *       <li>
    *          {@link Reader} - Raw contents of {@code Reader} will be serialized to remote resource.
    *       <li>
    *          {@link InputStream} - Raw contents of {@code InputStream} will be serialized to remote resource.
    *       <li>
    *          {@link NameValuePairSupplier} - Converted to a URL-encoded query.
    *    </ul>
    * @return This object (for method chaining).
    * @throws RestCallException Invalid input.
    */
   public RestRequest queryCustom(Object value) throws RestCallException {
      try {
         String q = null;
         if (value instanceof Reader)
            q = IOUtils.read((Reader)value);
         else if (value instanceof InputStream)
            q = IOUtils.read((InputStream)value);
         else
            q = stringify(value);  // Works for NameValuePairs.
         uriBuilder.setCustomQuery(q);
      } catch (IOException e) {
         throw new RestCallException(null, e, "Could not read custom query.");
      }
      return this;
   }

   RestRequest queryArg(EnumSet<AddFlag> flags, String name, Object value, HttpPartSchema schema, HttpPartSerializerSession serializer) throws RestCallException {
      flags = AddFlag.orDefault(flags);
      boolean isMulti = isEmpty(name) || "*".equals(name) || value instanceof NameValuePairSupplier || isNameValuePairArray(value);

      if (! isMulti)
         return innerQuery(flags, AList.of(serializedNameValuePair(name, value, QUERY, serializer, schema, flags)));

      List<NameValuePair> l = AList.of();

      if (BasicNameValuePair.canCast(value)) {
         l.add(BasicNameValuePair.cast(value));
      } else if (value instanceof NameValuePairSupplier) {
         for (Object o : (NameValuePairSupplier)value)
            l.add(BasicNameValuePair.cast(o));
      } else if (value instanceof Collection) {
         for (Object o : (Collection<?>)value)
            l.add(BasicNameValuePair.cast(o));
      } else if (value != null && value.getClass().isArray()) {
         for (int i = 0; i < Array.getLength(value); i++)
            l.add(BasicNameValuePair.cast(Array.get(value, i)));
      } else if (value instanceof Map) {
         for (Map.Entry<Object,Object> e : toMap(value).entrySet())
            l.add(serializedNameValuePair(e.getKey(), e.getValue(), QUERY, serializer, schema, flags));
      } else if (isBean(value)) {
         for (Map.Entry<String,Object> e : toBeanMap(value).entrySet())
            l.add(serializedNameValuePair(e.getKey(), e.getValue(), QUERY, serializer, schema, flags));
      } else {
         return queryCustom(value);
      }

      return innerQuery(flags, l);
   }

   private RestRequest innerQuery(EnumSet<AddFlag> flags, List<NameValuePair> params) {
      flags = AddFlag.orDefault(flags);
      params.removeIf(x -> x.getValue() == null);
      if (flags.contains(SKIP_IF_EMPTY))
         params.removeIf(x -> isEmpty(x.getValue()));
      if (flags.contains(REPLACE)) {
         List<NameValuePair> l = uriBuilder.getQueryParams();
         for (NameValuePair p : params)
            for (Iterator<NameValuePair> i = l.iterator(); i.hasNext();)
               if (i.next().getName().equals(p.getName()))
                  i.remove();
         l.addAll(params);
         uriBuilder.setParameters(l);
      } else if (flags.contains(PREPEND)) {
         List<NameValuePair> l = uriBuilder.getQueryParams();
         l.addAll(0, params);
         uriBuilder.setParameters(l);
      } else {
         uriBuilder.addParameters(params);
      }
      return this;
   }

   //------------------------------------------------------------------------------------------------------------------
   // Form data
   //------------------------------------------------------------------------------------------------------------------

   /**
    * Adds a form-data parameter to the request body.
    *
    * <h5 class='section'>Example:</h5>
    * <p class='bcode w800'>
    *    <jc>// Adds form data parameter "foo=bar|baz".</jc>
    *    <jv>client</jv>
    *       .formPost(<jsf>URI</jsf>)
    *       .formData(
    *          <jsf>APPEND</jsf>,
    *          <js>"foo"</js>, AList.<jsm>of</jsm>(<js>"bar"</js>,<js>"baz"</js>),
    *          HttpPartSchema.<jsf>T_ARRAY_PIPES</jsf>
    *       .run();
    * </p>
    *
    * @param flag How to add this parameter.
    *    <ul>
    *       <li>{@link AddFlag#APPEND APPEND} (default) - Append to end.
    *       <li>{@link AddFlag#PREPEND PREPEND} - Prepend to beginning.
    *       <li>{@link AddFlag#REPLACE REPLACE} - Delete any existing with same name and append to end.
    *    </ul>
    * @param name The parameter name.
    * @param value The parameter value.
    *    <ul>
    *       <li>Value can be any POJO or POJO {@link Supplier}.
    *       <li>Value converted to a string using the configured part serializer.
    *    </ul>
    * @param schema The schema object that defines the format of the output.
    *    <ul>
    *       <li>If <jk>null</jk>, defaults to {@link HttpPartSchema#DEFAULT}.
    *       <li>Only used if serializer is schema-aware (e.g. {@link OpenApiSerializer}).
    *    </ul>
    * @return This object (for method chaining).
    * @throws RestCallException Invalid input.
    */
   public RestRequest formData(AddFlag flag, String name, Object value, HttpPartSchema schema) throws RestCallException {
      return formDatas(flag, serializedNameValuePair(name, value, FORMDATA, partSerializer, schema, EnumSet.of(flag)));
   }

   /**
    * Adds a form-data parameter to the request body.
    *
    * <h5 class='section'>Example:</h5>
    * <p class='bcode w800'>
    *    <jc>// Adds form data parameter "foo=bar|baz".</jc>
    *    <jv>client</jv>
    *       .formPost(<jsf>URI</jsf>)
    *       .formData(<js>"foo"</js>, <js>"bar"</js>)
    *       .run();
    * </p>
    *
    * @param name The parameter name.
    * @param value The parameter value.
    *    <ul>
    *       <li>Value can be any POJO or POJO {@link Supplier}.
    *       <li>Value converted to a string using the configured part serializer.
    *    </ul>
    * @return This object (for method chaining).
    * @throws RestCallException Invalid input.
    */
   public RestRequest formData(String name, Object value) throws RestCallException {
      return formDatas(serializedNameValuePair(name, value, FORMDATA, partSerializer, null, null));
   }

   /**
    * Adds a form-data parameter to the request body.
    *
    * <h5 class='section'>Example:</h5>
    * <p class='bcode w800'>
    *    <jc>// Adds form data parameter "foo=bar".</jc>
    *    <jv>client</jv>
    *       .formPost(<jsf>URI</jsf>)
    *       .formData(BasicNameValuePair.<jsm>of</jsm>(<js>"foo"</js>, <js>"bar"</js>))
    *       .run();
    * </p>
    *
    * @param pair The parameter.
    * @return This object (for method chaining).
    * @throws RestCallException Invalid input.
    */
   public RestRequest formData(NameValuePair pair) throws RestCallException {
      return formDatas(pair);
   }

   /**
    * Adds a form-data parameter to the request body.
    *
    * <p>
    * The optional schema allows for specifying how part should be serialized (as a pipe-delimited list for example).
    *
    * <h5 class='section'>Example:</h5>
    * <p class='bcode w800'>
    *    <jc>// Adds form data parameter "foo=bar|baz".</jc>
    *    <jv>client</jv>
    *       .formPost(<jsf>URI</jsf>)
    *       .formData(
    *          <js>"foo"</js>, AList.<jsm>of</jsm>(<js>"bar"</js>,<js>"baz"</js>),
    *          HttpPartSchema.<jsf>T_ARRAY_PIPES</jsf>
    *    )
    *       .run();
    * </p>
    *
    * @param name The parameter name.
    * @param value The parameter value.
    *    <ul>
    *       <li>Value can be any POJO or POJO {@link Supplier}.
    *       <li>Value converted to a string using the configured part serializer.
    *    </ul>
    * @param schema The HTTP part schema.  Can be <jk>null</jk>.
    * @return This object (for method chaining).
    * @throws RestCallException Invalid input.
    */
   public RestRequest formData(String name, Object value, HttpPartSchema schema) throws RestCallException {
      return formDatas(serializedNameValuePair(name, value, FORMDATA, partSerializer, schema, null));
   }

   /**
    * Adds a form-data parameter to the request body.
    *
    * <h5 class='section'>Example:</h5>
    * <p class='bcode w800'>
    *    <jc>// Adds form data parameter "foo=bar".</jc>
    *    <jv>client</jv>
    *       .formPost(<jsf>URI</jsf>)
    *       .formData(
    *          <jsf>APPEND</jsf>,
    *          <js>"foo"</js>, <js>"bar"</js>
    *    )
    *       .run();
    * </p>
    *
    * @param flag How to add this parameter.
    *    <ul>
    *       <li>{@link AddFlag#APPEND APPEND} (default) - Append to end.
    *       <li>{@link AddFlag#PREPEND PREPEND} - Prepend to beginning.
    *       <li>{@link AddFlag#REPLACE REPLACE} - Delete any existing with same name and append to end.
    *    </ul>
    * @param name The parameter name.
    * @param value The parameter value.
    *    <ul>
    *       <li>Value can be any POJO or POJO {@link Supplier}.
    *       <li>Value converted to a string using the configured part serializer.
    *    </ul>
    * @return This object (for method chaining).
    * @throws RestCallException Invalid input.
    */
   public RestRequest formData(AddFlag flag, String name, Object value) throws RestCallException {
      return formDatas(flag, serializedNameValuePair(name, value, FORMDATA, partSerializer, null, EnumSet.of(flag)));
   }

   /**
    * Adds a form-data parameter to the request body.
    *
    * <h5 class='section'>Example:</h5>
    * <p class='bcode w800'>
    *    <jc>// Adds form data parameters "foo=bar&baz=qux".</jc>
    *    <jv>client</jv>
    *       .formPost(<jsf>URI</jsf>)
    *       .formDatas(
    *          BasicNameValuePair.<jsm>of</jsm>(<js>"foo"</js>,<js>"bar"</js>),
    *          AMap.<jsm>of</jsm>(<js>"baz"</js>,<js>"qux"</js>)
    *       )
    *       .run();
    * </p>
    *
    * @param params
    *    The parameters to set.
    *    <br>Can be any of the following types:
    *    <ul>
    *       <li>{@link NameValuePair}
    *       <li>{@link NameValuePairable}
    *       <li>{@link java.util.Map.Entry}
    *       <li>{@link NameValuePairSupplier}
    *       <li>{@link Map}
    *       <ul>
    *          <li>Values can be any POJO.
    *          <li>Values converted to a string using the configured part serializer.
    *       </ul>
    *       <li>A collection or array of anything on this list.
    * </ul>
    * @return This object (for method chaining).
    * @throws RestCallException Invalid input.
    */
   public RestRequest formDatas(Object...params) throws RestCallException {
      return formDatas(APPEND, params);
   }

   /**
    * Adds multiple form-data parameters to the request body.
    *
    * <h5 class='section'>Example:</h5>
    * <p class='bcode w800'>
    *    <jc>// Adds form data parameters "foo=bar&baz=qux".</jc>
    *    <jv>client</jv>
    *       .formPost(<jsf>URI</jsf>)
    *       .formDatas(
    *          <jsf>APPEND</jsf>,
    *          BasicNameValuePair.<jsm>of</jsm>(<js>"foo"</js>,<js>"bar"</js>),
    *          AMap.<jsm>of</jsm>(<js>"baz"</js>,<js>"qux"</js>)
    *       )
    *       .run();
    * </p>
    *
    * @param flag How to add this parameter.
    *    <ul>
    *       <li>{@link AddFlag#APPEND APPEND} (default) - Append to end.
    *       <li>{@link AddFlag#PREPEND PREPEND} - Prepend to beginning.
    *       <li>{@link AddFlag#REPLACE REPLACE} - Delete any existing with same name and append to end.
    *    </ul>
    * @param params
    *    The parameters to set.
    *    <br>Can be any of the following types:
    *    <ul>
    *       <li>{@link NameValuePair}
    *       <li>{@link NameValuePairable}
    *       <li>{@link java.util.Map.Entry}
    *       <li>{@link NameValuePairSupplier}
    *       <li>{@link Map}
    *       <ul>
    *          <li>Values can be any POJO.
    *          <li>Values converted to a string using the configured part serializer.
    *       </ul>
    *       <li>A collection or array of anything on this list.
    * </ul>
    * @return This object (for method chaining).
    * @throws RestCallException Invalid input.
    */
   public RestRequest formDatas(AddFlag flag, Object...params) throws RestCallException {
      List<NameValuePair> l = new ArrayList<>();
      for (Object o : params) {
         if (BasicNameValuePair.canCast(o)) {
            l.add(BasicNameValuePair.cast(o));
         } else if (o instanceof NameValuePairSupplier) {
            for (NameValuePair p : (NameValuePairSupplier)o)
               l.add(p);
         } else if (o instanceof Collection) {
            for (Object o2 : (Collection<?>)o)
               l.add(BasicNameValuePair.cast(o2));
         } else if (o != null && o.getClass().isArray()) {
            for (int i = 0; i < Array.getLength(o); i++)
               l.add(BasicNameValuePair.cast(Array.get(o, i)));
         } else if (o instanceof Map) {
            for (Map.Entry<Object,Object> e : toMap(o).entrySet())
               l.add(serializedNameValuePair(e.getKey(), e.getValue(), FORMDATA, partSerializer, null, EnumSet.of(flag)));
         } else if (isBean(o)) {
            for (Map.Entry<String,Object> e : toBeanMap(o).entrySet())
               l.add(serializedNameValuePair(e.getKey(), e.getValue(), FORMDATA, partSerializer, null, EnumSet.of(flag)));
         } else if (o != null) {
            throw new RestCallException(null, null, "Invalid type passed to formDatas(): {0}", className(o));
         }
      }
      return innerFormData(EnumSet.of(flag), l);
   }

   /**
    * Adds form-data parameters to the request body using free-form key/value pairs.
    *
    * <h5 class='section'>Example:</h5>
    * <p class='bcode w800'>
    *    <jc>// Creates form data "key1=val1&key2=val2".</jc>
    *    <jv>client</jv>
    *       .formPost(<jsf>URI</jsf>)
    *       .formDataPairs(<js>"key1"</js>,<js>"val1"</js>,<js>"key2"</js>,<js>"val2"</js>)
    *       .run();
    * </p>
    *
    * @param pairs The form-data key/value pairs.
    *    <ul>
    *       <li>Values can be any POJO.
    *       <li>Values converted to a string using the configured part serializer.
    *    </ul>
    * @return This object (for method chaining).
    * @throws RestCallException Invalid input.
    */
   public RestRequest formDataPairs(Object...pairs) throws RestCallException {
      if (pairs.length % 2 != 0)
         throw new RestCallException(null, null, "Odd number of parameters passed into formDataPairs()");
      for (int i = 0; i < pairs.length; i+=2)
         formDatas(serializedNameValuePair(pairs[i], pairs[i+1], FORMDATA, partSerializer, null, null));
      return this;
   }

   /**
    * Adds form-data parameters as the entire body of the request.
    *
    * <h5 class='section'>Example:</h5>
    * <p class='bcode w800'>
    *    <jc>// Creates form data "foo=bar&baz=qux".</jc>
    *    <jv>client</jv>
    *       .formPost(<jsf>URI</jsf>)
    *       .formDataCustom(<js>"foo=bar&baz=qux"</js>)
    *       .run();
    *
    *    <jc>// Creates form data "foo=bar&baz=qux" using StringEntity.</jc>
    *    <jv>client</jv>
    *       .formPost(<jsf>URI</jsf>)
    *       .formDataCustom(<jk>new</jk> StringEntity(<js>"foo=bar&baz=qux"</js>,<js>"application/x-www-form-urlencoded"</js>))
    *       .run();
    *
    *    <jc>// Creates form data "foo=bar&baz=qux" using StringEntity and body().</jc>
    *    <jv>client</jv>
    *       .formPost(<jsf>URI</jsf>)
    *       .body(<jk>new</jk> StringEntity(<js>"foo=bar&baz=qux"</js>,<js>"application/x-www-form-urlencoded"</js>))
    *       .run();
    * </p>
    *
    * @param value The parameter value.
    *    <br>Can be any of the following types:
    *    <ul class='spaced-list'>
    *       <li>
    *          {@link CharSequence}
    *       <li>
    *          {@link Reader} - Raw contents of {@code Reader} will be serialized to remote resource.
    *       <li>
    *          {@link InputStream} - Raw contents of {@code InputStream} will be serialized to remote resource.
    *       <li>
    *          {@link HttpResource}/{@link BasicHttpResource} - Raw contents will be serialized to remote resource.  Additional headers and media type will be set on request.
    *       <li>
    *          {@link HttpEntity}/{@link BasicHttpEntity} - Bypass Juneau serialization and pass HttpEntity directly to HttpClient.
    *       <li>
    *          {@link Object} - POJO to be converted to text using the {@link Serializer} registered with the
    *          {@link RestClient}.
    *       <li>
    *          {@link NameValuePairSupplier} - Converted to a URL-encoded FORM post.
    *    </ul>
    * @return This object (for method chaining).
    * @throws RestCallException Invalid input.
    */
   public RestRequest formDataCustom(Object value) throws RestCallException {
      contentType("application/x-www-form-urlencoded");
      body(value instanceof CharSequence ? new StringReader(value.toString()) : value);
      return this;
   }

   RestRequest formDataArg(EnumSet<AddFlag> flags, String name, Object value, HttpPartSchema schema, HttpPartSerializerSession serializer) throws RestCallException {
      flags = AddFlag.orDefault(flags);
      boolean isMulti = isEmpty(name) || "*".equals(name) || value instanceof NameValuePairSupplier || isNameValuePairArray(value);

      if (! isMulti)
         return innerFormData(flags, AList.of(serializedNameValuePair(name, value, FORMDATA, serializer, schema, flags)));

      List<NameValuePair> l = AList.of();

      if (BasicNameValuePair.canCast(value)) {
         l.add(BasicNameValuePair.cast(value));
      } else if (value instanceof NameValuePairSupplier) {
         for (Object o : (NameValuePairSupplier)value)
            l.add(BasicNameValuePair.cast(o));
      } else if (value instanceof Collection) {
         for (Object o : (Collection<?>)value)
            l.add(BasicNameValuePair.cast(o));
      } else if (value != null && value.getClass().isArray()) {
         for (int i = 0; i < Array.getLength(value); i++)
            l.add(BasicNameValuePair.cast(Array.get(value, i)));
      } else if (value instanceof Map) {
         for (Map.Entry<Object,Object> e : toMap(value).entrySet())
            l.add(serializedNameValuePair(e.getKey(), e.getValue(), FORMDATA, serializer, schema, flags));
      } else if (isBean(value)) {
         for (Map.Entry<String,Object> e : toBeanMap(value).entrySet())
            l.add(serializedNameValuePair(e.getKey(), e.getValue(), FORMDATA, serializer, schema, flags));
      } else {
         return formDataCustom(value);
      }

      return innerFormData(flags, l);
   }

   private RestRequest innerFormData(EnumSet<AddFlag> flags, List<NameValuePair> params) {
      input = null;
      flags = AddFlag.orDefault(flags);
      params.removeIf(x -> x.getValue() == null);
      if (flags.contains(SKIP_IF_EMPTY))
         params.removeIf(x -> isEmpty(x.getValue()));
      if (formData == null)
         formData = new ArrayList<>();
      if (flags.contains(REPLACE)) {
         for (NameValuePair p : params)
            for (Iterator<NameValuePair> i = formData.iterator(); i.hasNext();)
               if (i.next().getName().equals(p.getName()))
                  i.remove();
         formData.addAll(params);
      } else if (flags.contains(PREPEND)) {
         formData.addAll(0, params);
      } else {
         formData.addAll(params);
      }
      return this;
   }


   //------------------------------------------------------------------------------------------------------------------
   // Request body
   //------------------------------------------------------------------------------------------------------------------

   /**
    * Sets the body of this request.
    *
    * @param input
    *    The input to be sent to the REST resource (only valid for PUT/POST/PATCH) requests.
    *    <br>Can be of the following types:
    *    <ul class='spaced-list'>
    *       <li>
    *          {@link Reader} - Raw contents of {@code Reader} will be serialized to remote resource.
    *       <li>
    *          {@link InputStream} - Raw contents of {@code InputStream} will be serialized to remote resource.
    *       <li>
    *          {@link HttpResource}/{@link BasicHttpResource} - Raw contents will be serialized to remote resource.  Additional headers and media type will be set on request.
    *       <li>
    *          {@link HttpEntity}/{@link BasicHttpEntity} - Bypass Juneau serialization and pass HttpEntity directly to HttpClient.
    *       <li>
    *          {@link Object} - POJO to be converted to text using the {@link Serializer} registered with the
    *          {@link RestClient}.
    *       <li>
    *          {@link NameValuePairSupplier} - Converted to a URL-encoded FORM post.
    *       <li>
    *          A {@link Supplier} of anything on this list.
    *    </ul>
    * @return This object (for method chaining).
    * @throws RestCallException If a retry was attempted, but the entity was not repeatable.
    */
   public RestRequest body(Object input) throws RestCallException {
      this.input = input;
      this.hasInput = true;
      this.formData = null;
      return this;
   }

   /**
    * Sets the body of this request as straight text bypassing the serializer.
    *
    * <p class='bcode w800'>
    *    <jv>client</jv>
    *       .put(<js>"/foo"</js>)
    *       .body(<jk>new</jk> StringReader(<js>"foo"</js>))
    *       .contentType(""
    *       .run();
    *
    * <jv>client</jv>
    *       .put(<js>"/foo"</js>)
    *       .bodyString(<js>"foo"</js>)
    *       .run();
    * </p>
    *
    * <p>
    * Note that this is different than the following which will serialize <l>foo</l> as a JSON string <l>"foo"</l>.
    * <p class='bcode w800'>
    *    <jv>client</jv>
    *       .put(<js>"/foo"</js>)
    *       .json()
    *       .body(<js>"foo"</js>)
    *       .run();
    * </p>
    *
    * @param input
    *    The input to be sent to the REST resource (only valid for PUT/POST/PATCH) requests.
    * @return This object (for method chaining).
    * @throws RestCallException If a retry was attempted, but the entity was not repeatable.
    */
   public RestRequest bodyString(Object input) throws RestCallException {
      return body(input == null ? null : new StringReader(stringify(input)));
   }

   /**
    * Sets the body of this request.
    *
    * @param input
    *    The input to be sent to the REST resource (only valid for PUT/POST/PATCH) requests.
    *    <br>Can be of the following types:
    *    <ul class='spaced-list'>
    *       <li>
    *          {@link Reader} - Raw contents of {@code Reader} will be serialized to remote resource.
    *       <li>
    *          {@link InputStream} - Raw contents of {@code InputStream} will be serialized to remote resource.
    *       <li>
    *          {@link HttpResource}/{@link BasicHttpResource} - Raw contents will be serialized to remote resource.  Additional headers and media type will be set on request.
    *       <li>
    *          {@link HttpEntity}/{@link BasicHttpEntity} - Bypass Juneau serialization and pass HttpEntity directly to HttpClient.
    *       <li>
    *          {@link Object} - POJO to be converted to text using the {@link Serializer} registered with the
    *          {@link RestClient}.
    *       <li>
    *          {@link NameValuePairSupplier} - Converted to a URL-encoded FORM post.
    *       <li>
    *          A {@link Supplier} of anything on this list.
    *    </ul>
    * @param schema The schema object that defines the format of the output.
    *    <ul>
    *       <li>If <jk>null</jk>, defaults to {@link HttpPartSchema#DEFAULT}.
    *       <li>Only used if serializer is schema-aware (e.g. {@link OpenApiSerializer}).
    *    </ul>
    * @return This object (for method chaining).
    * @throws RestCallException If a retry was attempted, but the entity was not repeatable.
    */
   public RestRequest body(Object input, HttpPartSchema schema) throws RestCallException {
      this.input = input;
      this.hasInput = true;
      this.formData = null;
      this.requestBodySchema = schema;
      return this;
   }

   //-----------------------------------------------------------------------------------------------------------------
   // Headers
   //-----------------------------------------------------------------------------------------------------------------

   /**
    * Adds a header on the request.
    *
    * <h5 class='section'>Example:</h5>
    * <p class='bcode w800'>
    *    <jc>// Adds header "Foo: bar|baz".</jc>
    *    <jv>client</jv>
    *       .get(<jsf>URI</jsf>)
    *       .header(
    *          <jsf>APPEND</jsf>,
    *          <js>"Foo"</js>, AList.<jsm>of</jsm>(<js>"bar"</js>,<js>"baz"</js>)),
    *          HttpPartSchema.<jsf>T_ARRAY_PIPES</jsf>
    *       )
    *       .run();
    * </p>
    *
    * @param flag How to add this parameter.
    *    <ul>
    *       <li>{@link AddFlag#APPEND APPEND} (default) - Append to end.
    *       <li>{@link AddFlag#PREPEND PREPEND} - Prepend to beginning.
    *       <li>{@link AddFlag#REPLACE REPLACE} - Delete any existing with same name and append to end.
    *    </ul>
    * @param name The header name.
    * @param value The header value.
    *    <ul>
    *       <li>Value can be any POJO or POJO {@link Supplier}.
    *       <li>Value converted to a string using the configured part serializer.
    *    </ul>
    * @param schema The schema object that defines the format of the output.
    *    <ul>
    *       <li>If <jk>null</jk>, defaults to {@link HttpPartSchema#DEFAULT}.
    *       <li>Only used if serializer is schema-aware (e.g. {@link OpenApiSerializer}).
    *    </ul>
    * @return This object (for method chaining).
    * @throws RestCallException Invalid input.
    */
   public RestRequest header(AddFlag flag, String name, Object value, HttpPartSchema schema) throws RestCallException {
      return headers(flag, serializedHeader(name, value, partSerializer, schema, EnumSet.of(flag)));
   }

   /**
    * Appends a header on the request.
    *
    * <h5 class='section'>Example:</h5>
    * <p class='bcode w800'>
    *    <jc>// Adds header "Foo: bar".</jc>
    *    <jv>client</jv>
    *       .get(<jsf>URI</jsf>)
    *       .header(<js>"Foo"</js>, <js>"bar"</js>)
    *       .run();
    * </p>
    *
    * @param name The header name.
    * @param value The header value.
    *    <ul>
    *       <li>Value can be any POJO or POJO {@link Supplier}.
    *       <li>Value converted to a string using the configured part serializer.
    *    </ul>
    * @return This object (for method chaining).
    * @throws RestCallException Invalid input.
    */
   public RestRequest header(String name, Object value) throws RestCallException {
      return headers(serializedHeader(name, value, partSerializer, null, null));
   }

   /**
    * Appends a header on the request.
    *
    * <p>
    * The optional schema allows for specifying how part should be serialized (as a pipe-delimited list for example).
    *
    * <h5 class='section'>Example:</h5>
    * <p class='bcode w800'>
    *    <jc>// Adds header "Foo: bar|baz".</jc>
    *    <jv>client</jv>
    *       .get(<jsf>URI</jsf>)
    *       .header(
    *          <js>"Foo"</js>, AList.<jsm>of</jsm>(<js>"bar"</js>,<js>"baz"</js>),
    *          HttpPartSchema.<jsf>T_ARRAY_PIPES</jsf>
    *       )
    *       .run();
    * </p>
    *
    * @param name The header name.
    * @param value The header value.
    *    <ul>
    *       <li>Value can be any POJO or POJO {@link Supplier}.
    *       <li>Value converted to a string using the configured part serializer.
    *    </ul>
    * @param schema The HTTP part schema.  Can be <jk>null</jk>.
    * @return This object (for method chaining).
    * @throws RestCallException Invalid input.
    */
   public RestRequest header(String name, Object value, HttpPartSchema schema) throws RestCallException {
      return headers(serializedHeader(name, value, partSerializer, schema, null));
   }

   /**
    * Adds a header to the request.
    *
    * <h5 class='section'>Example:</h5>
    * <p class='bcode w800'>
    *    <jc>// Adds header "Foo: bar".</jc>
    *    <jv>client</jv>
    *       .get(<jsf>URI</jsf>)
    *       .header(
    *          <jsf>APPEND</jsf>,
    *          <js>"Foo"</js>, <js>"bar"</js>
    *       )
    *       .run();
    * </p>
    *
    * @param flag How to add this parameter.
    *    <ul>
    *       <li>{@link AddFlag#APPEND APPEND} (default) - Append to end.
    *       <li>{@link AddFlag#PREPEND PREPEND} - Prepend to beginning.
    *    <li>{@link AddFlag#REPLACE REPLACE} - Delete any existing with same name and append to end.
    *    </ul>
    * @param name The header name.
    * @param value The header value.
    *    <ul>
    *       <li>Value can be any POJO or POJO {@link Supplier}.
    *       <li>Value converted to a string using the configured part serializer.
    *    </ul>
    * @return This object (for method chaining).
    * @throws RestCallException Invalid input.
    */
   public RestRequest header(AddFlag flag, String name, Object value) throws RestCallException {
      return headers(flag, serializedHeader(name, value, partSerializer, null, EnumSet.of(flag)));
   }

   /**
    * Appends a header on the request.
    *
    * <h5 class='section'>Example:</h5>
    * <p class='bcode w800'>
    *    <jc>// Adds header "Foo: bar".</jc>
    *    <jv>client</jv>
    *       .get(<jsf>URI</jsf>)
    *       .header(BasicHeader.<jsm>of</jsm>(<js>"Foo"</js>, <js>"bar"</js>))
    *       .run();
    * </p>
    *
    * @param header The header to set.
    * @return This object (for method chaining).
    * @throws RestCallException Invalid input.
    */
   public RestRequest header(Header header) throws RestCallException {
      return headers(header);
   }

   /**
    * Appends multiple headers to the request.
    *
    * <h5 class='section'>Example:</h5>
    * <p class='bcode w800'>
    *    <jc>// Adds headers "Foo: bar" and "Baz: qux".</jc>
    *    <jv>client</jv>
    *       .get(<jsf>URI</jsf>)
    *       .headers(
    *          BasicHeader.<jsm>of</jsm>(<js>"Foo"</js>, <js>"bar"</js>),
    *          AMap.<jsm>of</jsm>(<js>"Baz"</js>, <js>"qux"</js>)
    *       )
    *       .run();
    * </p>
    *
    * @param headers
    *    The headers to set.
    *    <br>Can be any of the following types:
    *    <ul>
    *       <li>{@link Header} (including any subclasses such as {@link Accept})
    *       <li>{@link Headerable}
    *       <li>{@link java.util.Map.Entry}
    *       <li>{@link HeaderSupplier}
    *       <li>{@link Map}
    *       <ul>
    *          <li>Values can be any POJO.
    *          <li>Values converted to a string using the configured part serializer.
    *       </ul>
    *       <li>A collection or array of anything on this list.
    * </ul>
    * @return This object (for method chaining).
    * @throws RestCallException Invalid input.
    */
   public RestRequest headers(Object...headers) throws RestCallException {
      return headers(APPEND, headers);
   }

   /**
    * Sets multiple headers on the request.
    *
    * <h5 class='section'>Example:</h5>
    * <p class='bcode w800'>
    *    <jc>// Adds headers "Foo: bar" and "Baz: qux".</jc>
    *    <jv>client</jv>
    *       .get(<jsf>URI</jsf>)
    *       .headers(
    *          <jsf>APPEND</jsf>,
    *          BasicHeader.<jsm>of</jsm>(<js>"Foo"</js>, <js>"bar"</js>),
    *          AMap.<jsm>of</jsm>(<js>"Baz"</js>, <js>"qux"</js>)
    *       )
    *       .run();
    * </p>
    *
    * @param flag How to add this parameter.
    *    <ul>
    *       <li>{@link AddFlag#APPEND APPEND} (default) - Append to end.
    *       <li>{@link AddFlag#PREPEND PREPEND} - Prepend to beginning.
    *       <li>{@link AddFlag#REPLACE REPLACE} - Delete any existing with same name and append to end.
    *    </ul>
    * @param headers
    *    The headers to set.
    *    <br>Can be any of the following types:
    *    <ul>
    *       <li>{@link Header} (including any subclasses such as {@link Accept})
    *       <li>{@link Headerable}
    *       <li>{@link java.util.Map.Entry}
    *       <li>{@link HeaderSupplier}
    *       <li>{@link Map}
    *       <ul>
    *          <li>Values can be any POJO.
    *          <li>Values converted to a string using the configured part serializer.
    *       </ul>
    *       <li>A collection or array of anything on this list.
    * </ul>
    * @return This object (for method chaining).
    * @throws RestCallException Invalid input.
    */
   public RestRequest headers(AddFlag flag, Object...headers) throws RestCallException {
      List<Header> l = new ArrayList<>();
      for (Object o : headers) {
         if (BasicHeader.canCast(o)) {
            l.add(BasicHeader.cast(o));
         } else if (o instanceof HeaderSupplier) {
            for (Header h : (HeaderSupplier)o)
               l.add(h);
         } else if (o instanceof Collection) {
            for (Object o2 : (Collection<?>)o)
               l.add(BasicHeader.cast(o2));
         } else if (o != null && o.getClass().isArray()) {
            for (int i = 0; i < Array.getLength(o); i++)
               l.add(BasicHeader.cast(Array.get(o, i)));
         } else if (o instanceof Map) {
            for (Map.Entry<Object,Object> e : toMap(o).entrySet())
               l.add(serializedHeader(e.getKey(), e.getValue(), partSerializer, null, EnumSet.of(flag)));
         } else if (isBean(o)) {
            for (Map.Entry<String,Object> e : toBeanMap(o).entrySet())
               l.add(serializedHeader(e.getKey(), e.getValue(), partSerializer, null, EnumSet.of(flag)));
         } else if (o != null) {
            throw new RestCallException(null, null, "Invalid type passed to headers(): {0}", className(o));
         }
      }
      return innerHeaders(EnumSet.of(flag), l);
   }

   /**
    * Appends multiple headers on the request using freeform key/value pairs.
    *
    * <h5 class='section'>Example:</h5>
    * <p class='bcode w800'>
    *    <jc>// Adds headers "Foo: bar" and "Baz: qux".</jc>
    *    <jv>client</jv>
    *       .get(<jsf>URI</jsf>)
    *       .headers(<js>"Foo"</js>,<js>"bar"</js>,<js>"Baz"</js>,<js>"qux"</js>)
    *       .run();
    * </p>
    *
    * @param pairs The form-data key/value pairs.
    *    <ul>
    *       <li>Values can be any POJO.
    *       <li>Values converted to a string using the configured part serializer.
    *    </ul>
    * @return This object (for method chaining).
    * @throws RestCallException Invalid input.
    */
   public RestRequest headerPairs(Object...pairs) throws RestCallException {
      List<Header> l = new ArrayList<>();
      if (pairs.length % 2 != 0)
         throw new RestCallException(null, null, "Odd number of parameters passed into headerPairs()");
      for (int i = 0; i < pairs.length; i+=2)
         l.add(serializedHeader(pairs[i], pairs[i+1], partSerializer, null, null));
      return innerHeaders(EnumSet.of(APPEND), l);
   }

   RestRequest headerArg(EnumSet<AddFlag> flags, String name, Object value, HttpPartSchema schema, HttpPartSerializerSession serializer) throws RestCallException {
      flags = AddFlag.orDefault(flags);
      boolean isMulti = isEmpty(name) || "*".equals(name) || value instanceof HeaderSupplier || isHeaderArray(value);

      if (! isMulti)
         return innerHeaders(flags, AList.of(serializedHeader(name, value, serializer, schema, flags)));

      List<Header> l = AList.of();

      if (BasicHeader.canCast(value)) {
         l.add(BasicHeader.cast(value));
      } else if (value instanceof HeaderSupplier) {
         for (Object o : (HeaderSupplier)value)
            l.add(BasicHeader.cast(o));
      } else if (value instanceof Collection) {
         for (Object o : (Collection<?>)value)
            l.add(BasicHeader.cast(o));
      } else if (value != null && value.getClass().isArray()) {
         for (int i = 0; i < Array.getLength(value); i++)
            l.add(BasicHeader.cast(Array.get(value, i)));
      } else if (value instanceof Map) {
         for (Map.Entry<Object,Object> e : toMap(value).entrySet())
            l.add(serializedHeader(e.getKey(), e.getValue(), serializer, schema, flags));
      } else if (isBean(value)) {
         for (Map.Entry<String,Object> e : toBeanMap(value).entrySet())
            l.add(serializedHeader(e.getKey(), e.getValue(), serializer, schema, flags));
      } else if (value != null) {
         throw new RestCallException(null, null, "Invalid value type for header arg ''{0}'': {1}", name, className(value));
      }

      return innerHeaders(flags, l);
   }

   private RestRequest innerHeaders(EnumSet<AddFlag> flags, Collection<Header> headers) {
      flags = AddFlag.orDefault(flags);
      headers.removeIf(x -> x.getValue() == null);
      if (flags.contains(SKIP_IF_EMPTY))
         headers.removeIf(x -> isEmpty(x.getValue()));
      if (flags.contains(REPLACE)) {
         for (Header h : headers)
            removeHeaders(h.getName());
      } else if (flags.contains(PREPEND)) {
         for (Header h : AList.of(headers)) {
            for (Header h2 : getHeaders(h.getName()))
               headers.add(h2);
            removeHeaders(h.getName());
         }
      }
      for (Header h : headers) {
         addHeader(h);
      }
      return this;
   }

   /**
    * Convenience method for reading the current last value of the specified header.
    *
    * @param name The header name.
    * @return The header value or <jk>null</jk> if not set.
    */
   public String getHeader(String name) {
      return getHeader(name, null);
   }

   /**
    * Convenience method for reading the current last value of the specified header.
    *
    * @param name The header name.
    * @param def The default value if the header is not set.
    * @return The header value or the default value if not set.
    */
   public String getHeader(String name, String def) {
      Header h = getLastHeader(name);
      return h == null ? def : h.getValue();
   }

   //------------------------------------------------------------------------------------------------------------------
   // Specialized headers.
   //------------------------------------------------------------------------------------------------------------------

   /**
    * Sets the value for the <c>Accept</c> request header.
    *
    * <p>
    * This overrides the media type specified on the parser, but is overridden by calling
    * <code>header(<js>"Accept"</js>, value);</code>
    *
    * @param value The new header value.
    * @return This object (for method chaining).
    * @throws RestCallException Invalid input.
    */
   public RestRequest accept(Object value) throws RestCallException {
      return header("Accept", value);
   }

   /**
    * Sets the value for the <c>Accept-Charset</c> request header.
    *
    * <p>
    * This is a shortcut for calling <code>header(<js>"Accept-Charset"</js>, value);</code>
    *
    * @param value The new header value.
    * @return This object (for method chaining).
    * @throws RestCallException Invalid input.
    */
   public RestRequest acceptCharset(Object value) throws RestCallException {
      return header("Accept-Charset", value);
   }

   /**
    * Sets the value for the <c>Accept-Encoding</c> request header.
    *
    * <p>
    * This is a shortcut for calling <code>header(<js>"Accept-Encoding"</js>, value);</code>
    *
    * @param value The new header value.
    * @return This object (for method chaining).
    * @throws RestCallException Invalid input.
    */
   public RestRequest acceptEncoding(Object value) throws RestCallException {
      return header("Accept-Encoding", value);
   }

   /**
    * Sets the value for the <c>Accept-Language</c> request header.
    *
    * <p>
    * This is a shortcut for calling <code>header(<js>"Accept-Language"</js>, value);</code>
    *
    * @param value The new header value.
    * @return This object (for method chaining).
    * @throws RestCallException Invalid input.
    */
   public RestRequest acceptLanguage(Object value) throws RestCallException {
      return header("Accept-Language", value);
   }

   /**
    * Sets the value for the <c>Authorization</c> request header.
    *
    * <p>
    * This is a shortcut for calling <code>header(<js>"Authorization"</js>, value);</code>
    *
    * @param value The new header value.
    * @return This object (for method chaining).
    * @throws RestCallException Invalid input.
    */
   public RestRequest authorization(Object value) throws RestCallException {
      return header("Authorization", value);
   }

   /**
    * Sets the value for the <c>Cache-Control</c> request header.
    *
    * <p>
    * This is a shortcut for calling <code>header(<js>"Cache-Control"</js>, value);</code>
    *
    * @param value The new header value.
    * @return This object (for method chaining).
    * @throws RestCallException Invalid input.
    */
   public RestRequest cacheControl(Object value) throws RestCallException {
      return header("Cache-Control", value);
   }

   /**
    * Sets the value for the <c>Connection</c> request header.
    *
    * <p>
    * This is a shortcut for calling <code>header(<js>"Connection"</js>, value);</code>
    *
    * @param value The new header value.
    * @return This object (for method chaining).
    * @throws RestCallException Invalid input.
    */
   public RestRequest connection(Object value) throws RestCallException {
      return header("Connection", value);
   }

   /**
    * Sets the value for the <c>Content-Length</c> request header.
    *
    * <p>
    * This is a shortcut for calling <code>header(<js>"Content-Length"</js>, value);</code>
    *
    * @param value The new header value.
    * @return This object (for method chaining).
    * @throws RestCallException Invalid input.
    */
   public RestRequest contentLength(Object value) throws RestCallException {
      return header("Content-Length", value);
   }

   /**
    * Sets the value for the <c>Content-Type</c> request header.
    *
    * <p>
    * This overrides the media type specified on the serializer, but is overridden by calling
    * <code>header(<js>"Content-Type"</js>, value);</code>
    *
    * @param value The new header value.
    * @return This object (for method chaining).
    * @throws RestCallException Invalid input.
    */
   public RestRequest contentType(Object value) throws RestCallException {
      return header("Content-Type", value);
   }

   /**
    * Sets the value for the <c>Content-Encoding</c> request header.
    *
    * <p>
    * This is a shortcut for calling <code>header(<js>"Content-Encoding"</js>, value);</code>
    *
    * @param value The new header value.
    * @return This object (for method chaining).
    * @throws RestCallException Invalid input.
    */
   public RestRequest contentEncoding(Object value) throws RestCallException {
      return header("Content-Encoding", value);
   }

   /**
    * Sets the value for the <c>Date</c> request header.
    *
    * <p>
    * This is a shortcut for calling <code>header(<js>"Date"</js>, value);</code>
    *
    * @param value The new header value.
    * @return This object (for method chaining).
    * @throws RestCallException Invalid input.
    */
   public RestRequest date(Object value) throws RestCallException {
      return header("Date", value);
   }

   /**
    * Sets the value for the <c>Expect</c> request header.
    *
    * <p>
    * This is a shortcut for calling <code>header(<js>"Expect"</js>, value);</code>
    *
    * @param value The new header value.
    * @return This object (for method chaining).
    * @throws RestCallException Invalid input.
    */
   public RestRequest expect(Object value) throws RestCallException {
      return header("Expect", value);
   }

   /**
    * Sets the value for the <c>Forwarded</c> request header.
    *
    * <p>
    * This is a shortcut for calling <code>header(<js>"Forwarded"</js>, value);</code>
    *
    * @param value The new header value.
    * @return This object (for method chaining).
    * @throws RestCallException Invalid input.
    */
   public RestRequest forwarded(Object value) throws RestCallException {
      return header("Forwarded", value);
   }

   /**
    * Sets the value for the <c>From</c> request header.
    *
    * <p>
    * This is a shortcut for calling <code>header(<js>"From"</js>, value);</code>
    *
    * @param value The new header value.
    * @return This object (for method chaining).
    * @throws RestCallException Invalid input.
    */
   public RestRequest from(Object value) throws RestCallException {
      return header("From", value);
   }

   /**
    * Sets the value for the <c>Host</c> request header.
    *
    * <p>
    * This is a shortcut for calling <code>header(<js>"Host"</js>, value);</code>
    *
    * @param value The new header value.
    * @return This object (for method chaining).
    * @throws RestCallException Invalid input.
    */
   public RestRequest hostHeader(Object value) throws RestCallException {
      return header("Host", value);
   }

   /**
    * Sets the value for the <c>If-Match</c> request header.
    *
    * <p>
    * This is a shortcut for calling <code>header(<js>"If-Match"</js>, value);</code>
    *
    * @param value The new header value.
    * @return This object (for method chaining).
    * @throws RestCallException Invalid input.
    */
   public RestRequest ifMatch(Object value) throws RestCallException {
      return header("If-Match", value);
   }

   /**
    * Sets the value for the <c>If-Modified-Since</c> request header.
    *
    * <p>
    * This is a shortcut for calling <code>header(<js>"If-Modified-Since"</js>, value);</code>
    *
    * @param value The new header value.
    * @return This object (for method chaining).
    * @throws RestCallException Invalid input.
    */
   public RestRequest ifModifiedSince(Object value) throws RestCallException {
      return header("If-Modified-Since", value);
   }

   /**
    * Sets the value for the <c>If-None-Match</c> request header.
    *
    * <p>
    * This is a shortcut for calling <code>header(<js>"If-None-Match"</js>, value);</code>
    *
    * @param value The new header value.
    * @return This object (for method chaining).
    * @throws RestCallException Invalid input.
    */
   public RestRequest ifNoneMatch(Object value) throws RestCallException {
      return header("If-None-Match", value);
   }

   /**
    * Sets the value for the <c>If-Range</c> request header.
    *
    * <p>
    * This is a shortcut for calling <code>header(<js>"If-Range"</js>, value);</code>
    *
    * @param value The new header value.
    * @return This object (for method chaining).
    * @throws RestCallException Invalid input.
    */
   public RestRequest ifRange(Object value) throws RestCallException {
      return header("If-Range", value);
   }

   /**
    * Sets the value for the <c>If-Unmodified-Since</c> request header.
    *
    * <p>
    * This is a shortcut for calling <code>header(<js>"If-Unmodified-Since"</js>, value);</code>
    *
    * @param value The new header value.
    * @return This object (for method chaining).
    * @throws RestCallException Invalid input.
    */
   public RestRequest ifUnmodifiedSince(Object value) throws RestCallException {
      return header("If-Unmodified-Since", value);
   }

   /**
    * Sets the value for the <c>Max-Forwards</c> request header.
    *
    * <p>
    * This is a shortcut for calling <code>header(<js>"Max-Forwards"</js>, value);</code>
    *
    * @param value The new header value.
    * @return This object (for method chaining).
    * @throws RestCallException Invalid input.
    */
   public RestRequest maxForwards(Object value) throws RestCallException {
      return header("Max-Forwards", value);
   }

   /**
    * When called, <c>No-Trace: true</c> is added to requests.
    *
    * <p>
    * This gives the opportunity for the servlet to not log errors on invalid requests.
    * This is useful for testing purposes when you don't want your log file to show lots of errors that are simply the
    * results of testing.
    *
    * @return This object (for method chaining).
    * @throws RestCallException Invalid input.
    */
   public RestRequest noTrace() throws RestCallException {
      return header("No-Trace", true);
   }

   /**
    * Sets the value for the <c>Origin</c> request header.
    *
    * <p>
    * This is a shortcut for calling <code>header(<js>"Origin"</js>, value);</code>
    *
    * @param value The new header value.
    * @return This object (for method chaining).
    * @throws RestCallException Invalid input.
    */
   public RestRequest origin(Object value) throws RestCallException {
      return header("Origin", value);
   }

   /**
    * Sets the value for the <c>Pragma</c> request header.
    *
    * <p>
    * This is a shortcut for calling <code>header(<js>"Pragma"</js>, value);</code>
    *
    * @param value The new header value.
    * @return This object (for method chaining).
    * @throws RestCallException Invalid input.
    */
   public RestRequest pragma(Object value) throws RestCallException {
      return header("Pragma", value);
   }

   /**
    * Sets the value for the <c>Proxy-Authorization</c> request header.
    *
    * <p>
    * This is a shortcut for calling <code>header(<js>"Proxy-Authorization"</js>, value);</code>
    *
    * @param value The new header value.
    * @return This object (for method chaining).
    * @throws RestCallException Invalid input.
    */
   public RestRequest proxyAuthorization(Object value) throws RestCallException {
      return header("Proxy-Authorization", value);
   }

   /**
    * Sets the value for the <c>Range</c> request header.
    *
    * <p>
    * This is a shortcut for calling <code>header(<js>"Range"</js>, value);</code>
    *
    * @param value The new header value.
    * @return This object (for method chaining).
    * @throws RestCallException Invalid input.
    */
   public RestRequest range(Object value) throws RestCallException {
      return header("Range", value);
   }

   /**
    * Sets the value for the <c>Referer</c> request header.
    *
    * <p>
    * This is a shortcut for calling <code>header(<js>"Referer"</js>, value);</code>
    *
    * @param value The new header value.
    * @return This object (for method chaining).
    * @throws RestCallException Invalid input.
    */
   public RestRequest referer(Object value) throws RestCallException {
      return header("Referer", value);
   }

   /**
    * Sets the value for the <c>TE</c> request header.
    *
    * <p>
    * This is a shortcut for calling <code>header(<js>"TE"</js>, value);</code>
    *
    * @param value The new header value.
    * @return This object (for method chaining).
    * @throws RestCallException Invalid input.
    */
   public RestRequest te(Object value) throws RestCallException {
      return header("TE", value);
   }

   /**
    * Sets the value for the <c>User-Agent</c> request header.
    *
    * <p>
    * This is a shortcut for calling <code>header(<js>"User-Agent"</js>, value);</code>
    *
    * @param value The new header value.
    * @return This object (for method chaining).
    * @throws RestCallException Invalid input.
    */
   public RestRequest userAgent(Object value) throws RestCallException {
      return header("User-Agent", value);
   }

   /**
    * Sets the value for the <c>Upgrade</c> request header.
    *
    * <p>
    * This is a shortcut for calling <code>header(<js>"Upgrade"</js>, value);</code>
    *
    * @param value The new header value.
    * @return This object (for method chaining).
    * @throws RestCallException Invalid input.
    */
   public RestRequest upgrade(Object value) throws RestCallException {
      return header("Upgrade", value);
   }

   /**
    * Sets the value for the <c>Via</c> request header.
    *
    * <p>
    * This is a shortcut for calling <code>header(<js>"Via"</js>, value);</code>
    *
    * @param value The new header value.
    * @return This object (for method chaining).
    * @throws RestCallException Invalid input.
    */
   public RestRequest via(Object value) throws RestCallException {
      return header("Via", value);
   }

   /**
    * Sets the value for the <c>Warning</c> request header.
    *
    * <p>
    * This is a shortcut for calling <code>header(<js>"Warning"</js>, value);</code>
    *
    * @param value The new header value.
    * @return This object (for method chaining).
    * @throws RestCallException Invalid input.
    */
   public RestRequest warning(Object value) throws RestCallException {
      return header("Warning", value);
   }

   /**
    * Sets the client version by setting the value for the <js>"X-Client-Version"</js> header.
    *
    * @param value The version string (e.g. <js>"1.2.3"</js>)
    * @return This object (for method chaining).
    * @throws RestCallException Invalid input.
    */
   public RestRequest clientVersion(Object value) throws RestCallException {
      return header("X-Client-Version", value);
   }

   //------------------------------------------------------------------------------------------------------------------
   // Execution methods.
   //------------------------------------------------------------------------------------------------------------------

   /**
    * Runs this request and returns the resulting response object.
    *
    * <h5 class='section'>Example:</h5>
    * <p class='bcode w800'>
    *    <jk>try</jk> {
    *       <jk>int</jk> <jv>rc</jv> = <jv>client</jv>.get(<jsf>URI</jsf>).execute().getResponseStatus();
    *       <jc>// Succeeded!</jc>
    *    } <jk>catch</jk> (RestCallException <jv>e</jv>) {
    *       <jc>// Failed!</jc>
    *    }
    * </p>
    *
    * <ul class='notes'>
    *    <li>Calling this method multiple times will return the same original response object.
    *    <li>You must close the returned object if you do not consume the response or execute a method that consumes
    *       the response.
    *    <li>If you are only interested in the response code, use the {@link #complete()} method which will automatically
    *       consume the response so that you don't need to call {@link InputStream#close()} on the response body.
    * </ul>
    *
    * @return The response object.
    * @throws RestCallException If an exception or non-200 response code occurred during the connection attempt.
    */
   public RestResponse run() throws RestCallException {
      if (response != null)
         throw new RestCallException(response, null, "run() already called.");

      try {
         HttpEntityEnclosingRequestBase request2 = request instanceof HttpEntityEnclosingRequestBase ? (HttpEntityEnclosingRequestBase)request : null;
         request.setURI(uriBuilder.build());

         // Pick the serializer if it hasn't been overridden.
         Header h = getLastHeader("Content-Type");
         String contentType = h == null ? null : h.getValue();
         Serializer serializer = this.serializer;
         if (serializer == null)
            serializer = client.getMatchingSerializer(contentType);
         if (contentType == null && serializer != null)
            contentType = serializer.getPrimaryMediaType().toString();

         // Pick the parser if it hasn't been overridden.
         h = getLastHeader("Accept");
         String accept = h == null ? null : h.getValue();
         Parser parser = this.parser;
         if (parser == null)
            parser = client.getMatchingParser(accept);
         if (accept == null && parser != null)
            setHeader("Accept", parser.getPrimaryMediaType().toString());

         if (hasInput || formData != null) {

            if (request2 == null)
               throw new RestCallException(null, null, "Method does not support content entity.  Method={0}, URI={1}", getMethod(), getURI());

            Object input2 = input;

            if (input2 instanceof Supplier)
               input2 = ((Supplier<?>)input).get();

            HttpEntity entity = null;
            if (formData != null)
               entity = new UrlEncodedFormEntity(formData);
            else if (input2 instanceof NameValuePairSupplier)
               entity = new UrlEncodedFormEntity((NameValuePairSupplier)input2);
            else if (input2 instanceof HttpResource) {
               HttpResource r = (HttpResource)input2;
               headers(r.getHeaders());
               entity = (HttpEntity)input2;
            }
            else if (input2 instanceof HttpEntity)
               entity = (HttpEntity)input2;
            else if (input2 instanceof Reader)
               entity = new StringEntity(IOUtils.read((Reader)input2), getRequestContentType(TEXT_PLAIN));
            else if (input2 instanceof InputStream)
               entity = new InputStreamEntity((InputStream)input2, getRequestContentType(ContentType.APPLICATION_OCTET_STREAM));
            else if (serializer != null)
               entity = SerializedHttpEntity.of(input2, serializer).schema(requestBodySchema).contentType(contentType);
            else {
               if (input2 == null)
                  input2 = "";
               entity = new StringEntity(BeanContext.DEFAULT.getClassMetaForObject(input2).toString(input2), getRequestContentType(TEXT_PLAIN));
            }

            request2.setEntity(entity);
         }

         try {
            response = client.createResponse(this, client.run(target, request, context), parser);
         } catch (Exception e) {
            throw e;
         }

         if (isDebug() || client.logRequests == DetailLevel.FULL)
            response.cacheBody();

         for (RestCallInterceptor rci : interceptors)
            rci.onConnect(this, response);
         client.onConnect(this, response);

         String method = getMethod();
         int sc = response.getStatusCode();

         if (errorCodes.test(sc) && ! ignoreErrors) {
            throw new RestCallException(response, null, "HTTP method ''{0}'' call to ''{1}'' caused response code ''{2}, {3}''.\nResponse: \n{4}",
               method, getURI(), sc, response.getReasonPhrase(), response.getBody().asAbbreviatedString(1000));
         }

      } catch (RuntimeException | RestCallException e) {
         if (response != null)
            response.close();
         throw e;
      } catch (Exception e) {
         if (response != null)
            response.close();
         throw new RestCallException(response, e, "Call failed.");
      }

      return this.response;
   }

   /**
    * Same as {@link #run()} but allows you to run the call asynchronously.
    *
    * <h5 class='section'>Example:</h5>
    * <p class='bcode w800'>
    *    Future&lt;RestResponse&gt; <jv>future</jv> = <jv>client</jv>.get(<jsf>URI</jsf>).runFuture();
    *
    *    <jc>// Do some other stuff</jc>
    *
    *    <jk>try</jk> {
    *       String <jv>body</jv> = <jv>future</jv>.get().getBody().asString();
    *       <jc>// Succeeded!</jc>
    *    } <jk>catch</jk> (RestCallException <jv>e</jv>) {
    *       <jc>// Failed!</jc>
    *    }
    * </p>
    *
    * <ul class='notes'>
    *    <li>Use the {@link RestClientBuilder#executorService(ExecutorService, boolean)} method to customize the
    *       executor service used for creating {@link Future Futures}.
    * </ul>
    *
    * @return The HTTP status code.
    * @throws RestCallException If the executor service was not defined.
    */
   public Future<RestResponse> runFuture() throws RestCallException {
      return client.getExecutorService().submit(
         new Callable<RestResponse>() {
            @Override /* Callable */
            public RestResponse call() throws Exception {
               return run();
            }
         }
      );
   }

   /**
    * Same as {@link #run()} but immediately calls {@link RestResponse#consume()} to clean up the response.
    *
    * <p>
    * Use this method if you're only interested in the status line of the response and not the response entity.
    * Attempts to call any of the methods on the response object that retrieve the body (e.g. {@link RestResponseBody#asReader()}
    * will cause a {@link RestCallException} to be thrown.
    *
    * <ul class='notes'>
    *    <li>You do not need to execute {@link InputStream#close()} on the response body to consume the response.
    * </ul>
    *
    * <h5 class='section'>Example:</h5>
    * <p class='bcode w800'>
    *  <jc>// Get the response code.
    *  // No need to call close() on the RestResponse object.</jc>
    *  <jk>int</jk> <jv>rc</jv> = <jv>client</jv>.get(<jsf>URI</jsf>).complete().getResponseCode();
    * </p>
    *
    * @return The response object.
    * @throws RestCallException If an exception or non-200 response code occurred during the connection attempt.
    */
   public RestResponse complete() throws RestCallException {
      return run().consume();
   }

   /**
    * Same as {@link #complete()} but allows you to run the call asynchronously.
    *
    * <h5 class='section'>Example:</h5>
    * <p class='bcode w800'>
    *    Future&lt;RestResponse&gt; <jv>future</jv> = <jv>client</jv>.get(<jsf>URI</jsf>).completeFuture();
    *
    *    <jc>// Do some other stuff</jc>
    *
    *    <jk>int</jk> <jv>rc</jv> = <jv>future</jv>.get().getResponseStatus();
    * </p>
    *
    * <ul class='notes'>
    *    <li>Use the {@link RestClientBuilder#executorService(ExecutorService, boolean)} method to customize the
    *       executor service used for creating {@link Future Futures}.
    *    <li>You do not need to execute {@link InputStream#close()} on the response body to consume the response.
    * </ul>
    *
    * @return The HTTP status code.
    * @throws RestCallException If the executor service was not defined.
    */
   public Future<RestResponse> completeFuture() throws RestCallException {
      return client.getExecutorService().submit(
         new Callable<RestResponse>() {
            @Override /* Callable */
            public RestResponse call() throws Exception {
               return complete();
            }
         }
      );
   }

   /**
    * Returns <jk>true</jk> if this request has a body.
    *
    * @return <jk>true</jk> if this request has a body.
    */
   public boolean hasHttpEntity() {
      return request instanceof HttpEntityEnclosingRequestBase;
   }

   /**
    * Returns the body of this request.
    *
    * @return The body of this request, or <jk>null</jk> if it doesn't have a body.
    */
   public HttpEntity getHttpEntity() {
      return hasHttpEntity() ? ((HttpEntityEnclosingRequestBase)request).getEntity() : null;
   }

   /**
    * Logs a message.
    *
    * @param level The log level.
    * @param t The throwable cause.
    * @param msg The message with {@link MessageFormat}-style arguments.
    * @param args The arguments.
    * @return This object (for method chaining).
    */
   public RestRequest log(Level level, Throwable t, String msg, Object...args) {
      client.log(level, t, msg, args);
      return this;
   }

   /**
    * Logs a message.
    *
    * @param level The log level.
    * @param msg The message with {@link MessageFormat}-style arguments.
    * @param args The arguments.
    * @return This object (for method chaining).
    */
   public RestRequest log(Level level, String msg, Object...args) {
      client.log(level, msg, args);
      return this;
   }

   //-----------------------------------------------------------------------------------------------------------------
   // HttpRequestBase pass-through methods.
   //-----------------------------------------------------------------------------------------------------------------

   /**
    * Sets the actual request configuration.
    *
    * @param value The new value.
    * @return This object (for method chaining).
    */
   public RestRequest config(RequestConfig value) {
      request.setConfig(value);
      return this;
   }

   /**
    * Sets {@link Cancellable} for the ongoing operation.
    *
    * @param cancellable The cancellable object.
    * @return This object (for method chaining).
    */
   public RestRequest cancellable(Cancellable cancellable) {
      request.setCancellable(cancellable);
      return this;
   }

   /**
    * Sets the protocol version for this request.
    *
    * @param version The protocol version for this request.
    * @return This object (for method chaining).
    */
   public RestRequest protocolVersion(ProtocolVersion version) {
      request.setProtocolVersion(version);
      return this;
   }

   /**
    * Used in combination with {@link #cancellable(Cancellable)}.
    *
    * @return This object (for method chaining).
    */
   public RestRequest completed() {
      request.completed();
      return this;
   }

   // -----------------------------------------------------------------------------------------------------------------
   // HttpUriRequest pass-through methods.
   // -----------------------------------------------------------------------------------------------------------------

   /**
    * Returns the HTTP method this request uses, such as GET, PUT, POST, or other.
    *
    * @return The HTTP method this request uses, such as GET, PUT, POST, or other.
    */
   @Override /* HttpUriRequest */
   public String getMethod() {
      return request.getMethod();
   }

   /**
    * Returns the original request URI.
    *
    * <ul class='notes'>
    *    <li>URI remains unchanged in the course of request execution and is not updated if the request is redirected to another location.
    * </ul>
    *
    * @return The original request URI.
    */
   @Override /* HttpUriRequest */
   public URI getURI() {
      return request.getURI();
   }

   /**
    * Returns the original request URI as a simple string.
    *
    * <ul class='notes'>
    *    <li>URI remains unchanged in the course of request execution and is not updated if the request is redirected to another location.
    * </ul>
    *
    * @return The original request URI.
    */
   public String getUri() {
      return getURI().toString();
   }

   /**
    * Aborts this http request. Any active execution of this method should return immediately.
    *
    * If the request has not started, it will abort after the next execution.
    * <br>Aborting this request will cause all subsequent executions with this request to fail.
    */
   @Override /* HttpUriRequest */
   public void abort() throws UnsupportedOperationException {
      request.abort();
   }

   @Override /* HttpUriRequest */
   public boolean isAborted() {
      return request.isAborted();
   }

   /**
    * Returns the request line of this request.
    *
    * @return The request line.
    */
   @Override /* HttpRequest */
   public RequestLine getRequestLine() {
      return request.getRequestLine();
   }

   /**
    * Returns the protocol version this message is compatible with.
    *
    * @return The protocol version.
    */
   @Override /* HttpMessage */
   public ProtocolVersion getProtocolVersion() {
      return request.getProtocolVersion();
   }

   /**
    * Checks if a certain header is present in this message.
    *
    * Header values are ignored.
    *
    * @param name The header name to check for.
    * @return <jk>true</jk> if at least one header with this name is present.
    */
   @Override /* HttpMessage */
   public boolean containsHeader(String name) {
      return request.containsHeader(name);
   }

   /**
    * Returns all the headers with a specified name of this message.
    *
    * Header values are ignored.
    * <br>Headers are ordered in the sequence they will be sent over a connection.
    *
    * @param name The name of the headers to return.
    * @return The headers whose name property equals name.
    */
   @Override /* HttpMessage */
   public Header[] getHeaders(String name) {
      return request.getHeaders(name);
   }

   /**
    * Returns the first header with a specified name of this message.
    *
    * Header values are ignored.
    * <br>If there is more than one matching header in the message the first element of {@link #getHeaders(String)} is returned.
    * <br>If there is no matching header in the message <jk>null</jk> is returned.
    *
    * @param name The name of the header to return.
    * @return The first header whose name property equals name or <jk>null</jk> if no such header could be found.
    */
   @Override /* HttpMessage */
   public Header getFirstHeader(String name) {
      return request.getFirstHeader(name);
   }

   /**
    * Returns the last header with a specified name of this message.
    *
    * Header values are ignored.
    * <br>If there is more than one matching header in the message the last element of {@link #getHeaders(String)} is returned.
    * <br>If there is no matching header in the message null is returned.
    *
    * @param name The name of the header to return.
    * @return The last header whose name property equals name or <jk>null</jk> if no such header could be found.
    */
   @Override /* HttpMessage */
   public Header getLastHeader(String name) {
      return request.getLastHeader(name);
   }

   /**
    * Returns all the headers of this message.
    *
    * Headers are ordered in the sequence they will be sent over a connection.
    *
    * @return All the headers of this message
    */
   @Override /* HttpMessage */
   public Header[] getAllHeaders() {
      return request.getAllHeaders();
   }

   /**
    * Adds a header to this message.
    *
    * The header will be appended to the end of the list.
    *
    * <ul class='notes'>
    *    <li>{@link #header(Header)} is an equivalent method and the preferred method for fluent-style coding.
    * </ul>
    *
    * @param header The header to append.
    */
   @Override /* HttpMessage */
   public void addHeader(Header header) {
      request.addHeader(header);
   }

   /**
    * Adds a header to this message.
    *
    * The header will be appended to the end of the list.
    *
    * <ul class='notes'>
    *    <li>{@link #header(String,Object)} is an equivalent method and the preferred method for fluent-style coding.
    * </ul>
    *
    * @param name The name of the header.
    * @param value The value of the header.
    */
   @Override /* HttpMessage */
   public void addHeader(String name, String value) {
      request.addHeader(name, value);
   }

   /**
    * Overwrites the first header with the same name.
    *
    * The new header will be appended to the end of the list, if no header with the given name can be found.
    *
    * @param header The header to set.
    */
   @Override /* HttpMessage */
   public void setHeader(Header header) {
      request.setHeader(header);
   }

   /**
    * Overwrites the first header with the same name.
    *
    * The new header will be appended to the end of the list, if no header with the given name can be found.
    *
    * @param name The name of the header.
    * @param value The value of the header.
    */
   @Override /* HttpMessage */
   public void setHeader(String name, String value) {
      request.setHeader(name, value);
   }

   /**
    * Overwrites all the headers in the message.
    *
    * @param headers The array of headers to set.
    */
   @Override /* HttpMessage */
   public void setHeaders(Header[] headers) {
      request.setHeaders(headers);
   }

   /**
    * Removes a header from this message.
    *
    * @param header The header to remove.
    */
   @Override /* HttpMessage */
   public void removeHeader(Header header) {
      request.removeHeader(header);
   }

   /**
    * Removes all headers with a certain name from this message.
    *
    * @param name The name of the headers to remove.
    */
   @Override /* HttpMessage */
   public void removeHeaders(String name) {
      request.removeHeaders(name);
   }

   /**
    * Returns an iterator of all the headers.
    *
    * @return Iterator that returns {@link Header} objects in the sequence they are sent over a connection.
    */
   @Override /* HttpMessage */
   public HeaderIterator headerIterator() {
      return request.headerIterator();
   }

   /**
    * Returns an iterator of the headers with a given name.
    *
    * @param name the name of the headers over which to iterate, or <jk>null</jk> for all headers.
    * @return Iterator that returns {@link Header} objects with the argument name in the sequence they are sent over a connection.
    */
   @Override /* HttpMessage */
   public HeaderIterator headerIterator(String name) {
      return request.headerIterator(name);
   }

   /**
    * Returns the parameters effective for this message as set by {@link #setParams(HttpParams)}.
    *
    * @return The parameters effective for this message as set by {@link #setParams(HttpParams)}.
    * @deprecated Use constructor parameters of configuration API provided by HttpClient.
    */
   @Override /* HttpMessage */
   @Deprecated
   public HttpParams getParams() {
      return request.getParams();
   }

   /**
    * Provides parameters to be used for the processing of this message.
    *
    * @param params The parameters.
    * @deprecated Use constructor parameters of configuration API provided by HttpClient.
    */
   @Override /* HttpMessage */
   @Deprecated
   public void setParams(HttpParams params) {
      request.setParams(params);
   }

   /**
    * Returns the actual request configuration.
    *
    * @return The actual request configuration.
    */
   @Override /* Configurable */
   public RequestConfig getConfig() {
      return request.getConfig();
   }

   // -----------------------------------------------------------------------------------------------------------------
   // Utility methods
   // -----------------------------------------------------------------------------------------------------------------

   private ContentType getRequestContentType(ContentType def) {
      Header h = request.getFirstHeader("Content-Type");
      if (h != null) {
         String s = h.getValue();
         if (! isEmpty(s))
            return ContentType.create(s);
      }
      return def;
   }

   @Override
   public OMap getProperties() {
      return super.getProperties();
   }

   @SuppressWarnings("unchecked")
   private static Map<Object,Object> toMap(Object o) {
      return (Map<Object,Object>)o;
   }

   private static SerializedNameValuePair serializedNameValuePair(Object key, Object value, HttpPartType type, HttpPartSerializerSession serializer, HttpPartSchema schema, EnumSet<AddFlag> flags) {
      return key == null ? null : new SerializedNameValuePair(stringify(key), value, type, serializer, schema, flags == null ? false : flags.contains(SKIP_IF_EMPTY));
   }

   private static SerializedHeader serializedHeader(Object key, Object value, HttpPartSerializerSession serializer, HttpPartSchema schema, EnumSet<AddFlag> flags) {
      return key == null ? null : new SerializedHeader(stringify(key), value, serializer, schema, flags == null ? false : flags.contains(SKIP_IF_EMPTY));
   }

   private static boolean isNameValuePairArray(Object o) {
      if (o == null || ! o.getClass().isArray())
         return false;
      if (NameValuePair.class.isAssignableFrom(o.getClass().getComponentType()))
         return true;
      return false;
   }

   private static boolean isHeaderArray(Object o) {
      if (o == null || ! o.getClass().isArray())
         return false;
      if (Header.class.isAssignableFrom(o.getClass().getComponentType()))
         return true;
      return false;
   }

   //-----------------------------------------------------------------------------------------------------------------
   // Other methods
   //-----------------------------------------------------------------------------------------------------------------

   @Override /* Session */
   public OMap toMap() {
      return super.toMap()
         .a("RestCall", new DefaultFilteringOMap()
            .a("client", client)
            .a("hasInput", hasInput)
            .a("ignoreErrors", ignoreErrors)
            .a("interceptors", interceptors)
            .a("partSerializer", partSerializer)
            .a("requestBodySchema", requestBodySchema)
            .a("response", response)
            .a("serializer", serializer)
         );
   }
}