/*
 * 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.marshall.serializer;

import static java.util.Collections.*;
import static org.apache.juneau.commons.utils.CollectionUtils.*;
import static org.apache.juneau.commons.utils.Shorts.*;
import static org.apache.juneau.commons.utils.StringUtils.*;
import static org.apache.juneau.commons.utils.SystemUtils.*;

import java.io.*;
import java.net.*;
import java.util.*;
import java.util.function.*;

import org.apache.juneau.commons.collections.*;
import org.apache.juneau.commons.http.*;
import org.apache.juneau.marshall.*;
import org.apache.juneau.marshall.json5.*;
import org.apache.juneau.marshall.soap.*;
import org.apache.juneau.marshall.stream.*;

/**
 * Parent class for all Juneau serializers.
 *
 * <h5 class='topic'>Description</h5>
 * <p>
 * Base serializer class that serves as the parent class for all serializers.
 *
 * <p>
 * The purpose of this class is:
 * <ul>
 *    <li>Maintain a read-only configuration state of a serializer.
 *    <li>Create session objects used for serializing POJOs (i.e. {@link SerializerSession}).
 *    <li>Provide convenience methods for serializing POJOs without having to construct session objects.
 * </ul>
 *
 * <p>
 * Subclasses should (but are not required to) extend directly from {@link OutputStreamSerializer} or {@link WriterSerializer} depending on
 * whether it's a stream or character based serializer.
 *
 * <p>
 * Subclasses must implement serialization via one of the following methods:
 * <ul class='javatree'>
 *    <li class='jmp'>{@link #doWrite(SerializerSession, SerializerPipe, Object)}
 *    <li class='jmp'>{@link SerializerSession#doWrite(SerializerPipe, Object)}
 * </ul>
 * <br>
 *
 * <h5 class='section'>Notes:</h5><ul>
 *    <li class='note'>This class is thread safe and reusable.
 * </ul>
 *
 * <h5 class='section'>See Also:</h5><ul>
 *    <li class='link'><a class="doclink" href="https://juneau.apache.org/docs/topics/SerializersAndParsers">Serializers and Parsers</a>

 * </ul>
 */
@SuppressWarnings({
   "java:S1192", // Duplicated literals (argument/property names) read more clearly inline than as constants
   "rawtypes" // createSerializerBuilder() returns the raw Builder because the concrete SELF type is only known reflectively via Context.createBuilder(c)
})
public class Serializer extends MarshallingTraverseContext {

   /**
    * Builder class.
    */
   @SuppressWarnings({
      "java:S119" // 'SELF' (CRTP self-type) is intentional and clearer than a single-letter name.
   })
   public abstract static class Builder<SELF extends Builder<SELF>> extends MarshallingTraverseContext.Builder<SELF> {

      private boolean addBeanTypes;
      private boolean addRootType;
      private boolean keepNullProperties;
      private boolean nonDefault;
      private boolean sortCollections;
      private boolean sortMaps;
      private boolean trimEmptyCollections;
      private boolean trimEmptyMaps;
      private boolean trimStrings;
      private Class<? extends SerializerListener> listener;
      private String accept;
      private String produces;
      private UriContext uriContext;
      private UriRelativity uriRelativity;
      private UriResolution uriResolution;

      /**
       * Constructor, default settings.
       */
      protected Builder() {
         produces = null;
         accept = null;
         addBeanTypes = env("Serializer.addBeanTypes", false);
         addRootType = env("Serializer.addRootType", false);
         keepNullProperties = env("Serializer.keepNullProperties", false);
         nonDefault = env("Serializer.nonDefault", false);
         sortCollections = env("Serializer.sortCollections", false);
         sortMaps = env("Serializer.sortMaps", false);
         trimEmptyCollections = env("Serializer.trimEmptyCollections", false);
         trimEmptyMaps = env("Serializer.trimEmptyMaps", false);
         trimStrings = env("Serializer.trimStrings", false);
         uriContext = UriContext.DEFAULT;
         uriRelativity = UriRelativity.RESOURCE;
         uriResolution = UriResolution.NONE;
         listener = null;
      }

      /**
       * Copy constructor.
       *
       * @param copyFrom The builder to copy from.
       *    <br>Cannot be <jk>null</jk>.
       */
      protected Builder(Builder<?> copyFrom) {
         super(reqnn("copyFrom", copyFrom));
         produces = copyFrom.produces;
         accept = copyFrom.accept;
         addBeanTypes = copyFrom.addBeanTypes;
         addRootType = copyFrom.addRootType;
         keepNullProperties = copyFrom.keepNullProperties;
         nonDefault = copyFrom.nonDefault;
         sortCollections = copyFrom.sortCollections;
         sortMaps = copyFrom.sortMaps;
         trimEmptyCollections = copyFrom.trimEmptyCollections;
         trimEmptyMaps = copyFrom.trimEmptyMaps;
         trimStrings = copyFrom.trimStrings;
         uriContext = copyFrom.uriContext;
         uriRelativity = copyFrom.uriRelativity;
         uriResolution = copyFrom.uriResolution;
         listener = copyFrom.listener;
      }

      /**
       * Copy constructor.
       *
       * @param copyFrom The bean to copy from.
       *    <br>Cannot be <jk>null</jk>.
       */
      protected Builder(Serializer copyFrom) {
         super(reqnn("copyFrom", copyFrom));
         produces = copyFrom.produces;
         accept = copyFrom.accept;
         addBeanTypes = copyFrom.addBeanTypes;
         addRootType = copyFrom.addRootType;
         keepNullProperties = copyFrom.keepNullProperties;
         nonDefault = copyFrom.nonDefault;
         sortCollections = copyFrom.sortCollections;
         sortMaps = copyFrom.sortMaps;
         trimEmptyCollections = copyFrom.trimEmptyCollections;
         trimEmptyMaps = copyFrom.trimEmptyMaps;
         trimStrings = copyFrom.trimStrings;
         uriContext = copyFrom.getUriContext();
         uriRelativity = copyFrom.getUriRelativity();
         uriResolution = copyFrom.getUriResolution();
         listener = copyFrom.listener;
      }

      /**
       *    Specifies the accept media types that the serializer can handle.
       *
       *    <p>
       *    Can contain meta-characters per the <c>media-type</c> specification of <a class="doclink" href="https://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html">RFC2616/14.1</a>
       *    <p>
       *    If empty, then assumes the only media type supported is <c>produces</c>.
       *    <p>
       *    For example, if this serializer produces <js>"application/json"</js> but should handle media types of
       *    <js>"application/json"</js> and <js>"text/json"</js>, then the arguments should be:
       *    <p class='bjava'>
       *       <jv>builder</jv>.produces(<js>"application/json"</js>);
       *       <jv>builder</jv>.accept(<js>"application/json,text/json"</js>);
       *    </p>
       * <p>
       * The accept value can also contain q-values.
       *
       * @param value The value for this setting.
       *    <br>Can be <jk>null</jk> (will default to the value specified by {@link #produces(String)}).
       * @return This object.
       */
      public SELF accept(String value) {
         accept = value;
         return self();
      }

      /**
       * Add <js>"_type"</js> properties when needed.
       *
       * <p>
       * When enabled, <js>"_type"</js> properties will be added to beans if their type cannot be inferred
       * through reflection.
       *
       * <p>
       * This is used to recreate the correct objects during parsing if the object types cannot be inferred.
       * <br>For example, when serializing a <c>Map&lt;String,Object&gt;</c> field where the bean class cannot be determined from
       * the type of the values.
       *
       * <p>
       * Note the differences between the following settings:
       * <ul class='javatree'>
       *    <li class='jf'>{@link #addRootType()} - Affects whether <js>'_type'</js> is added to root node.
       *    <li class='jf'>{@link #addBeanTypes()} - Affects whether <js>'_type'</js> is added to any nodes.
       * </ul>
       *
       * <h5 class='section'>Example:</h5>
       * <p class='bjava'>
       *    <jc>// Create a serializer that adds _type to nodes.</jc>
       *    WriterSerializer <jv>serializer</jv> = JsonSerializer
       *       .<jsm>create</jsm>()
       *       .addBeanTypes()
       *       .build();
       *
       *    <jc>// Our map of beans to serialize.</jc>
       *    <ja>@Marshalled</ja>(typeName=<js>"mybean"</js>)
       *    <jk>public class</jk> MyBean {
       *       <jk>public</jk> String <jf>foo</jf> = <js>"bar"</js>;
       *    }
       *    JsonMap <jv>myMap</jv> = JsonMap.of(<js>"foo"</js>, <jk>new</jk> MyBean());
       *
       *    <jc>// Will contain:  {"foo":{"_type":"mybean","foo":"bar"}}</jc>
       *    String <jv>json</jv> = <jv>serializer</jv>.write(<jv>myMap</jv>);
       * </p>
       *
       * <p>
       * <b>Token streams:</b> the cursor's raw structural methods do not emit <c>"_type"</c>;
       * however this setting IS honored by
       * {@link TokenWriter#object(Object) TokenWriter.object(Object)}
       * when walking a bean.
       *
       * @return This object.
       */
      public SELF addBeanTypes() {
         return addBeanTypes(true);
      }

      /**
       * Same as {@link #addBeanTypes()} but allows you to explicitly specify the value.
       *
       * @param value The value for this setting.
       * @return This object.
       */
      public SELF addBeanTypes(boolean value) {
         addBeanTypes = value;
         return self();
      }

      /**
       * Add type attribute to root nodes.
       *
       * <p>
       * When enabled, <js>"_type"</js> properties will be added to top-level beans.
       *
       * <p>
       * When disabled, it is assumed that the parser knows the exact Java POJO type being parsed, and therefore top-level
       * type information that might normally be included to determine the data type will not be serialized.
       *
       * <p>
       * For example, when serializing a top-level POJO with a {@link Marshalled#typeName() @Marshalled(typeName)} value, a
       * <js>'_type'</js> attribute will only be added when this setting is enabled.
       *
       * <p>
       * Note the differences between the following settings:
       * <ul class='javatree'>
       *    <li class='jf'>{@link #addRootType()} - Affects whether <js>'_type'</js> is added to root node.
       *    <li class='jf'>{@link #addBeanTypes()} - Affects whether <js>'_type'</js> is added to any nodes.
       * </ul>
       *
       * <h5 class='section'>Example:</h5>
       * <p class='bjava'>
       *    <jc>// Create a serializer that adds _type to root node.</jc>
       *    WriterSerializer <jv>serializer</jv>= JsonSerializer
       *       .<jsm>create</jsm>()
       *       .addRootType()
       *       .build();
       *
       *    <jc>// Our bean to serialize.</jc>
       *    <ja>@Marshalled</ja>(typeName=<js>"mybean"</js>)
       *    <jk>public class</jk> MyBean {
       *       <jk>public</jk> String <jf>foo</jf> = <js>"bar"</js>;
       *    }
       *
       *    <jc>// Will contain:  {"_type":"mybean","foo":"bar"}</jc>
       *    String <jv>json</jv> = <jv>serializer</jv>.write(<jk>new</jk> MyBean());
       * </p>
       *
       * <p>
       * <b>Token streams:</b> the cursor's raw structural methods do not emit <c>"_type"</c>;
       * however this setting IS honored by
       * {@link TokenWriter#object(Object) TokenWriter.object(Object)}
       * for the root value.
       *
       * @return This object.
       */
      public SELF addRootType() {
         return addRootType(true);
      }

      /**
       * Same as {@link #addRootType()} but allows you to explicitly specify the value.
       *
       * @param value The value for this setting.
       * @return This object.
       */
      public SELF addRootType(boolean value) {
         addRootType = value;
         return self();
      }

      @Override /* Overridden from Context.Builder<?> */
      public Serializer build() {
         return build(Serializer.class);
      }

      @Override /* Overridden from Context.Builder<?> */
      public abstract SELF copy();

      /**
       * Returns the current value for the 'accept' property.
       *
       * @return The current value for the 'accept' property.
       */
      public String getAccept() { return accept; }

      /**
       * Returns the current value for the 'produces' property.
       *
       * @return The current value for the 'produces' property.
       */
      public String getProduces() { return produces; }

      @Override /* Overridden from Context.Builder<?> */
      public HashKey hashKey() {
         // @formatter:off
         return HashKey.of(
            super.hashKey(),
            produces,
            accept,
            addBeanTypes,
            addRootType,
            keepNullProperties,
            nonDefault,
            sortCollections,
            sortMaps,
            trimEmptyCollections,
            trimEmptyMaps,
            trimStrings,
            uriContext,
            uriRelativity,
            uriResolution,
            listener
         );
         // @formatter:on
      }

      /**
       * Don't trim null bean property values.
       *
       * <p>
       * When enabled, null bean values will be serialized to the output.
       *
       * <h5 class='section'>Notes:</h5><ul>
       *    <li class='note'>Not enabling this setting will cause <c>Map</c>s with <jk>null</jk> values to be lost during parsing.
       * </ul>
       *
       * <h5 class='section'>Example:</h5>
       * <p class='bjava'>
       *    <jc>// Create a serializer that serializes null properties.</jc>
       *    WriterSerializer <jv>serializer</jv> = JsonSerializer
       *       .<jsm>create</jsm>()
       *       .keepNullProperties()
       *       .build();
       *
       *    <jc>// Our bean to serialize.</jc>
       *    <jk>public class</jk> MyBean {
       *       <jk>public</jk> String <jf>foo</jf> = <jk>null</jk>;
       *    }
       *
       *    <jc>// Will contain "{foo:null}".</jc>
       *    String <jv>json</jv> = <jv>serializer</jv>.write(<jk>new</jk> MyBean());
       * </p>
       *
       * <p>
       * <b>Token streams:</b> the cursor's raw structural methods always emit what the caller
       * asks for; however this setting IS honored by
       * {@link TokenWriter#object(Object) TokenWriter.object(Object)}
       * during a bean walk.
       *
       * @return This object.
       */
      public SELF keepNullProperties() {
         return keepNullProperties(true);
      }

      /**
       * Same as {@link #keepNullProperties()} but allows you to explicitly specify the value.
       *
       * @param value The value for this setting.
       * @return This object.
       */
      public SELF keepNullProperties(boolean value) {
         keepNullProperties = value;
         return self();
      }

      /**
       * Don't serialize bean properties whose values equal the default for their type.
       *
       * <p>
       * When enabled, bean properties whose current value equals the type's natural default are omitted from
       * the serialized output. This is the Juneau analog of Jackson's <c>JsonInclude.Include.NON_DEFAULT</c>
       * inclusion mode.
       *
       * <p>
       * The notion of "default" depends on the property type:
       * <ul class='spaced-list'>
       *    <li>Primitives and primitive wrappers (<code><jk>int</jk></code>, <code>Integer</code>,
       *       <code><jk>boolean</jk></code>, <code>Boolean</code>, etc.) use the Java type default
       *       (<c>0</c>, <c>false</c>, <code>'\0'</code>, <jk>null</jk>).
       *    <li>Bean properties on bean-typed property values use a <i>reference instance</i> of the bean type —
       *       instantiated once via the no-arg constructor and cached on the {@link ClassMeta} — and the
       *       property is omitted when its current value equals that reference's value.
       *    <li>When no reference instance can be built (no accessible no-arg constructor, or instantiation
       *       throws), <c>nonDefault</c> is silently skipped for that bean — the property is emitted normally
       *       rather than failing the serialize.
       * </ul>
       *
       * <p>
       * <b>Equality semantics:</b> value-equals-default uses {@link Objects#equals}, with numeric values
       * compared by mathematical value (BigDecimal.compareTo-style) so <c>1.0</c> equals <c>1</c>,
       * <c>0.0</c> equals <c>-0.0</c>, and <code>BigDecimal(<js>"1.0"</js>)</code> equals
       * <code>BigDecimal(<js>"1"</js>)</code>.
       *
       * <p>
       * <b>Precedence:</b> the serialize-side inclusion knobs short-circuit in a fixed order — first "omit" wins:
       * <ol>
       *    <li><jk>null</jk> values (including {@link Optional#empty()}) are governed by
       *       {@link #keepNullProperties()}.
       *    <li>Non-<jk>null</jk> string values are normalized by {@link #trimStrings()}.
       *    <li>Empty collections / arrays / maps are omitted by {@link #trimEmptyCollections()} /
       *       {@link #trimEmptyMaps()}.
       *    <li>Surviving values that equal their type's default are omitted by <c>nonDefault</c>.
       * </ol>
       * <jk>null</jk> is resolved by <c>keepNullProperties</c>, not treated as a <c>nonDefault</c> case.
       *
       * <h5 class='section'>Example:</h5>
       * <p class='bjava'>
       *    <jc>// Create a serializer that omits default-valued properties.</jc>
       *    WriterSerializer <jv>serializer</jv> = JsonSerializer
       *       .<jsm>create</jsm>()
       *       .nonDefault()
       *       .build();
       *
       *    <jc>// Our bean to serialize.</jc>
       *    <jk>public class</jk> MyBean {
       *       <jk>public int</jk> <jf>count</jf>;            <jc>// Default 0; omitted unless set to non-zero.</jc>
       *       <jk>public</jk> String <jf>name</jf> = <js>"x"</js>; <jc>// Bean-default is "x"; only omitted when value equals "x".</jc>
       *    }
       *
       *    <jc>// Produces "{}" because both fields equal their defaults.</jc>
       *    String <jv>json</jv> = <jv>serializer</jv>.write(<jk>new</jk> MyBean());
       * </p>
       *
       * <h5 class='section'>See Also:</h5><ul>
       *    <li class='link'><a class="doclink" href="https://juneau.apache.org/docs/topics/NullAndInclusionPolicies">Null &amp; Inclusion Policies</a>
       * </ul>
       *
       * @return This object.
       * @since 10.0.0
       */
      public SELF nonDefault() {
         return nonDefault(true);
      }

      /**
       * Same as {@link #nonDefault()} but allows you to explicitly specify the value.
       *
       * @param value The value for this setting.
       * @return This object.
       * @since 10.0.0
       */
      public SELF nonDefault(boolean value) {
         nonDefault = value;
         return self();
      }

      /**
       * Serializer listener.
       *
       * <p>
       * Class used to listen for errors and warnings that occur during serialization.
       *
       * <h5 class='section'>Example:</h5>
       * <p class='bjava'>
       *    <jc>// Define our serializer listener.</jc>
       *    <jc>// Simply captures all errors.</jc>
       *    <jk>public class</jk> MySerializerListener <jk>extends</jk> SerializerListener {
       *
       *       <jc>// A simple property to store our events.</jc>
       *       <jk>public</jk> List&lt;String&gt; <jf>events</jf> = <jk>new</jk> LinkedList&lt;&gt;();
       *
       *       <ja>@Override</ja>
       *       <jk>public</jk> &lt;T&gt; <jk>void</jk> onError(SerializerSession <jv>session</jv>, Throwable <jv>throwable</jv>, String <jv>msg</jv>) {
       *          <jf>events</jf>.add(<jv>session</jv>.getLastLocation() + <js>","</js> + <jv>msg</jv> + <js>","</js> + <jv>throwable</jv>);
       *       }
       *    }
       *
       *    <jc>// Create a serializer using our listener.</jc>
       *    WriterSerializer <jv>serializer</jv> = JsonSerializer
       *       .<jsm>create</jsm>()
       *       .listener(MySerializerListener.<jk>class</jk>)
       *       .build();
       *
       *    <jc>// Create a session object.</jc>
       *    <jc>// Needed because listeners are created per-session.</jc>
       *    <jk>try</jk> (WriterSerializerSession <jv>session</jv> = <jv>serializer</jv>.createSession()) {
       *
       *       <jc>// Serialize a bean.</jc>
       *       String <jv>json</jv> = <jv>session</jv>.write(<jk>new</jk> MyBean());
       *
       *       <jc>// Get the listener.</jc>
       *       MySerializerListener <jv>listener</jv> = <jv>session</jv>.getListener(MySerializerListener.<jk>class</jk>);
       *
       *       <jc>// Dump the results to the console.</jc>
       *       Json5.<jsf>DEFAULT</jsf>.println(<jv>listener</jv>.<jf>events</jf>);
       *    }
       * </p>
       *
       * <p>
       * <b>Token streams:</b> this setting is not honored by {@link TokenWritable#writeTokens(Object) writeTokens}
       * &mdash; listeners are POJO-level observers with no token-layer analog.
       *
       * @param value
       *    The new value for this property.
       *    <br>Can be <jk>null</jk> (no listener will be used, listener methods will not be called).
       * @return This object.
       */
      public SELF listener(Class<? extends SerializerListener> value) {
         listener = value;
         return self();
      }

      /**
       * Specifies the media type that this serializer produces.
       *
       * @param value The value for this setting.
       *    <br>Can be <jk>null</jk> (clears the produces media type).
       * @return This object.
       */
      public SELF produces(String value) {
         produces = value;
         return self();
      }

      /**
       * Sort arrays and collections alphabetically.
       *
       * <p>
       * When enabled, copies and sorts the contents of arrays and collections before serializing them.
       *
       * <p>
       * Note that this introduces a performance penalty since it requires copying the existing collection.
       *
       * <h5 class='section'>Example:</h5>
       * <p class='bjava'>
       *    <jc>// Create a serializer that sorts arrays and collections before serialization.</jc>
       *    WriterSerializer <jv>serializer</jv> = JsonSerializer
       *       .<jsm>create</jsm>()
       *       .sortCollections()
       *       .build();
       *
       *    <jc>// An unsorted array</jc>
       *    String[] <jv>myArray</jv> = {<js>"foo"</js>,<js>"bar"</js>,<js>"baz"</js>};
       *
       *    <jc>// Produces ["bar","baz","foo"]</jc>
       *    String <jv>json</jv> = <jv>serializer</jv>.write(<jv>myArray</jv>);
       * </p>
       *
       * <p>
       * <b>Token streams:</b> the cursor's raw structural methods emit elements in the order the
       * caller emits them.  This setting IS honored by
       * {@link TokenWriter#object(Object) TokenWriter.object(Object)}
       * when walking a {@link Collection} or array.
       *
       * @return This object.
       */
      public SELF sortCollections() {
         return sortCollections(true);
      }

      /**
       * Same as {@link #sortCollections()} but allows you to explicitly specify the value.
       *
       * @param value The value for this setting.
       * @return This object.
       */
      public SELF sortCollections(boolean value) {
         sortCollections = value;
         return self();
      }

      /**
       * Sort maps alphabetically.
       *
       * <p>
       * When enabled, copies and sorts the contents of maps by their keys before serializing them.
       *
       * <p>
       * Note that this introduces a performance penalty.
       *
       * <h5 class='section'>Example:</h5>
       * <p class='bjava'>
       *    <jc>// Create a serializer that sorts maps before serialization.</jc>
       *    WriterSerializer <jv>serializer</jv> = JsonSerializer
       *       .<jsm>create</jsm>()
       *       .sortMaps()
       *       .build();
       *
       *    <jc>// An unsorted map.</jc>
       *    JsonMap <jv>myMap</jv> = JsonMap.<jsm>of</jsm>(<js>"foo"</js>,1,<js>"bar"</js>,2,<js>"baz"</js>,3);
       *
       *    <jc>// Produces {"bar":2,"baz":3,"foo":1}</jc>
       *    String <jv>json</jv> = <jv>serializer</jv>.write(<jv>myMap</jv>);
       * </p>
       *
       * <p>
       * <b>Token streams:</b> the cursor's raw structural methods emit map / bean entries in the
       * order the caller emits them.  This setting IS honored by
       * {@link TokenWriter#object(Object) TokenWriter.object(Object)}
       * when walking a {@link Map} or bean.
       *
       * @return This object.
       */
      public SELF sortMaps() {
         return sortMaps(true);
      }

      /**
       * Same as {@link #sortMaps()} but allows you to explicitly specify the value.
       *
       * @param value The value for this setting.
       * @return This object.
       */
      public SELF sortMaps(boolean value) {
         sortMaps = value;
         return self();
      }

      /**
       * Trim empty lists and arrays.
       *
       * <p>
       * When enabled, empty lists and arrays will not be serialized.
       *
       * <p>
       * Note that enabling this setting has the following effects on parsing:
       * <ul class='spaced-list'>
       *    <li>
       *       Map entries with empty list values will be lost.
       *    <li>
       *       Bean properties with empty list values will not be set.
       * </ul>
       *
       * <h5 class='section'>Example:</h5>
       * <p class='bjava'>
       *    <jc>// Create a serializer that skips empty arrays and collections.</jc>
       *    WriterSerializer <jv>serializer</jv> = JsonSerializer
       *       .<jsm>create</jsm>()
       *       .trimEmptyCollections()
       *       .build();
       *
       *    <jc>// A bean with a field with an empty array.</jc>
       *    <jk>public class</jk> MyBean {
       *       <jk>public</jk> String[] <jf>foo</jf> = {};
       *    }
       *
       *    <jc>// Produces {}</jc>
       *    String <jv>json</jv> = <jv>serializer</jv>.write(<jk>new</jk> MyBean());
       * </p>
       *
       * <p>
       * <b>Token streams:</b> the cursor's raw structural methods emit what the caller asks for.
       * This setting IS honored by
       * {@link TokenWriter#object(Object) TokenWriter.object(Object)}
       * during a bean walk &mdash; bean / map fields whose value is an empty collection or array
       * are skipped.
       *
       * @return This object.
       */
      public SELF trimEmptyCollections() {
         return trimEmptyCollections(true);
      }

      /**
       * Same as {@link #trimEmptyCollections()} but allows you to explicitly specify the value.
       *
       * @param value The value for this setting.
       * @return This object.
       */
      public SELF trimEmptyCollections(boolean value) {
         trimEmptyCollections = value;
         return self();
      }

      /**
       * Trim empty maps.
       *
       * <p>
       * When enabled, empty map values will not be serialized to the output.
       *
       * <p>
       * Note that enabling this setting has the following effects on parsing:
       * <ul class='spaced-list'>
       *    <li>
       *       Bean properties with empty map values will not be set.
       * </ul>
       *
       * <h5 class='section'>Example:</h5>
       * <p class='bjava'>
       *    <jc>// Create a serializer that skips empty maps.</jc>
       *    WriterSerializer <jv>serializer</jv> = JsonSerializer
       *       .<jsm>create</jsm>()
       *       .trimEmptyMaps()
       *       .build();
       *
       *    <jc>// A bean with a field with an empty map.</jc>
       *    <jk>public class</jk> MyBean {
       *       <jk>public</jk> JsonMap <jf>foo</jf> = JsonMap.<jsm>of</jsm>();
       *    }
       *
       *    <jc>// Produces {}</jc>
       *    String <jv>json</jv> = <jv>serializer</jv>.write(<jk>new</jk> MyBean());
       * </p>
       *
       * <p>
       * <b>Token streams:</b> the cursor's raw structural methods emit what the caller asks for.
       * This setting IS honored by
       * {@link TokenWriter#object(Object) TokenWriter.object(Object)}
       * during a bean walk &mdash; bean / map fields whose value is an empty map are skipped.
       *
       * @return This object.
       */
      public SELF trimEmptyMaps() {
         return trimEmptyMaps(true);
      }

      /**
       * Same as {@link #trimEmptyMaps()} but allows you to explicitly specify the value.
       *
       * @param value The value for this setting.
       * @return This object.
       */
      public SELF trimEmptyMaps(boolean value) {
         trimEmptyMaps = value;
         return self();
      }

      /**
       * Trim strings.
       *
       * <p>
       * When enabled, string values will be trimmed of whitespace using {@link String#trim()} before being serialized.
       *
       * <h5 class='section'>Example:</h5>
       * <p class='bjava'>
       *    <jc>// Create a serializer that trims strings before serialization.</jc>
       *    WriterSerializer <jv>serializer</jv> = JsonSerializer
       *       .<jsm>create</jsm>()
       *       .trimStrings()
       *       .build();
       *
       * <jc>// A map with space-padded keys/values</jc>
       *    JsonMap <jv>myMap</jv> = JsonMap.<jsm>of</jsm>(<js>" foo "</js>, <js>" bar "</js>);
       *
       *    <jc>// Produces "{foo:'bar'}"</jc>
       *    String <jv>json</jv> = <jv>serializer</jv>.toString(<jv>myMap</jv>);
       * </p>
       *
       * @return This object.
       */
      public SELF trimStrings() {
         return trimStrings(true);
      }

      /**
       * Same as {@link #trimStrings()} but allows you to explicitly specify the value.
       *
       * @param value The value for this setting.
       * @return This object.
       */
      public SELF trimStrings(boolean value) {
         trimStrings = value;
         return self();
      }

      /**
       * URI context bean.
       *
       * <p>
       * Bean used for resolution of URIs to absolute or root-relative form.
       *
       * <h5 class='section'>Example:</h5>
       * <p class='bjava'>
       *    <jc>// Our URI contextual information.</jc>
       *    String <jv>authority</jv> = <js>"http://localhost:10000"</js>;
       *    String <jv>contextRoot</jv> = <js>"/myContext"</js>;
       *    String <jv>servletPath</jv> = <js>"/myServlet"</js>;
       *    String <jv>pathInfo</jv> = <js>"/foo"</js>;
       *
       *    <jc>// Create a UriContext object.</jc>
       *    UriContext <jv>uriContext</jv> = <jk>new</jk> UriContext(<jv>authority</jv>, <jv>contextRoot</jv>, <jv>servletPath</jv>, <jv>pathInfo</jv>);
       *
       *    <jc>// Associate it with our serializer.</jc>
       *    WriterSerializer <jv>serializer</jv> = JsonSerializer
       *       .<jsm>create</jsm>()
       *       .uriContext(<jv>uriContext</jv>)
       *       .uriRelativity(<jsf>RESOURCE</jsf>)  <jc>// Assume relative paths are relative to servlet.</jc>
       *       .uriResolution(<jsf>ABSOLUTE</jsf>)  <jc>// Serialize URLs as absolute paths.</jc>
       *       .build();
       *
       *    <jc>// A relative URL</jc>
       *    URL <jv>myUrl</jv> = <jk>new</jk> URL(<js>"bar"</js>);
       *
       *    <jc>// Produces "http://localhost:10000/myContext/myServlet/foo/bar"</jc>
       *    String <jv>json</jv> = <jv>serializer</jv>.toString(<jv>myUrl</jv>);
       * </p>
       *
       * <h5 class='section'>See Also:</h5><ul>
       *    <li class='link'><a class="doclink" href="https://juneau.apache.org/docs/topics/MarshallingUris">URIs</a>
       * </ul>
       *
       * <p>
       * <b>Token streams:</b> this setting is not honored by {@link TokenWritable#writeTokens(Object) writeTokens}
       * &mdash; URI rewriting is a databind concern; the token layer emits string values verbatim.
       *
       * @param value The new value for this property.
       *    <br>Can be <jk>null</jk> (defaults to <c>UriContext.DEFAULT</c>).
       * @return This object.
       */
      public SELF uriContext(UriContext value) {
         uriContext = value;
         return self();
      }

      /**
       * URI relativity.
       *
       * <p>
       * Defines what relative URIs are relative to when serializing any of the following:
       * <ul>
       *    <li>{@link URI}
       *    <li>{@link URL}
       *    <li>Properties and classes annotated with {@link Uri @Uri}
       * </ul>
       *
       * <p>
       * See {@link #uriContext(UriContext)} for examples.
       *
       * <ul class='values javatree'>
       *    <li class='jf'>{@link UriRelativity#RESOURCE}
       *       - Relative URIs should be considered relative to the servlet URI.
       *    <li class='jf'>{@link UriRelativity#PATH_INFO}
       *       - Relative URIs should be considered relative to the request URI.
       * </ul>
       *
       * <h5 class='section'>See Also:</h5><ul>
       *    <li class='link'><a class="doclink" href="https://juneau.apache.org/docs/topics/MarshallingUris">URIs</a>
       * </ul>
       *
       * <p>
       * <b>Token streams:</b> this setting is not honored by {@link TokenWritable#writeTokens(Object) writeTokens}
       * &mdash; URI rewriting is a databind concern.
       *
       * @param value
       *    The new value for this property.
       *    <br>The default is {@link UriRelativity#RESOURCE}
       *    <br>Can be <jk>null</jk> (defaults to <c>UriRelativity.RESOURCE</c>).
       * @return This object.
       */
      public SELF uriRelativity(UriRelativity value) {
         uriRelativity = value;
         return self();
      }

      /**
       * URI resolution.
       *
       * <p>
       * Defines the resolution level for URIs when serializing any of the following:
       * <ul>
       *    <li>{@link URI}
       *    <li>{@link URL}
       *    <li>Properties and classes annotated with {@link Uri @Uri}
       * </ul>
       *
       * <p>
       * See {@link #uriContext(UriContext)} for examples.
       *
       * <ul class='values javatree'>
       *    <li class='jf'>{@link UriResolution#ABSOLUTE}
       *       - Resolve to an absolute URL (e.g. <js>"http://host:port/context-root/servlet-path/path-info"</js>).
       *    <li class='jf'>{@link UriResolution#ROOT_RELATIVE}
       *       - Resolve to a root-relative URL (e.g. <js>"/context-root/servlet-path/path-info"</js>).
       *    <li class='jf'>{@link UriResolution#NONE}
       *       - Don't do any URL resolution.
       * </ul>
       *
       * <h5 class='section'>See Also:</h5><ul>
       *    <li class='link'><a class="doclink" href="https://juneau.apache.org/docs/topics/MarshallingUris">URIs</a>
       * </ul>
       *
       * <p>
       * <b>Token streams:</b> this setting is not honored by {@link TokenWritable#writeTokens(Object) writeTokens}
       * &mdash; URI rewriting is a databind concern.
       *
       * @param value
       *    The new value for this property.
       *    <br>The default is {@link UriResolution#NONE}
       *    <br>Can be <jk>null</jk> (defaults to <c>UriResolution.NONE</c>).
       * @return This object.
       */
      public SELF uriResolution(UriResolution value) {
         uriResolution = value;
         return self();
      }


   }

   /**
    * Concrete default builder leaf for the non-subclassed {@link Serializer#create()} / {@link Serializer#copy()} path.
    */
   public static final class DefaultBuilder extends Builder<DefaultBuilder> {

      DefaultBuilder() {}

      DefaultBuilder(Serializer copyFrom) {
         super(copyFrom);
      }

      DefaultBuilder(Builder<?> copyFrom) {
         super(copyFrom);
      }

      @Override /* Overridden from Context.Builder<?> */
      public DefaultBuilder copy() {
         return new DefaultBuilder(this);
      }
   }

   /**
    * Represents no Serializer.
    */
   public abstract static class Null extends Serializer {
      @SuppressWarnings({
         "java:S1186" // Constructor required by Serializer parent class, even though Null is abstract and never instantiated directly
      })
      private Null(Builder<?> builder) {
         super(builder);
      }
   }

   /**
    * Creates a new builder for this object.
    *
    * @return A new builder.
    */
   @SuppressWarnings({
      "java:S1452" // Self-typed builder: Builder<?> is the only non-raw, leaf-free return; chaining + build() unaffected.
   })
   public static Builder<?> create() {
      return new DefaultBuilder();
   }

   /**
    * Instantiates a builder of the specified serializer class.
    *
    * <p>
    * Looks for a public static method called <c>create</c> that returns an object that can be passed into a public
    * or protected constructor of the class.
    *
    * @param c The serializer class to create a builder for.
    *    <br>Must not be <jk>null</jk>.
    * @return A new builder.
    */
   public static Builder createSerializerBuilder(Class<? extends Serializer> c) {
      return (Builder)Context.createBuilder(c);
   }

   protected final boolean addBeanTypes;
   protected final boolean addRootType;
   protected final boolean keepNullProperties;
   protected final boolean nonDefault;
   protected final boolean sortCollections;
   protected final boolean sortMaps;
   protected final boolean trimEmptyCollections;
   protected final boolean trimEmptyMaps;
   protected final boolean trimStrings;
   protected final Class<? extends SerializerListener> listener;
   protected final String accept;
   protected final String produces;
   private final UriContext uriContext;
   private final UriRelativity uriRelativity;
   private final UriResolution uriResolution;
   private final MediaRanges acceptRanges;
   private final List<MediaType> acceptMediaTypes;
   private final MediaType producesMediaType;

   /**
    * Constructor
    *
    * @param builder The builder for this object.
    *    <br>Cannot be <jk>null</jk>.
    */
   protected Serializer(Builder<?> builder) {
      super(builder);

      accept = builder.accept;
      addBeanTypes = builder.addBeanTypes;
      addRootType = builder.addRootType;
      keepNullProperties = builder.keepNullProperties;
      listener = builder.listener;
      nonDefault = builder.nonDefault;
      produces = builder.produces;
      sortCollections = builder.sortCollections;
      sortMaps = builder.sortMaps;
      trimEmptyCollections = builder.trimEmptyCollections;
      trimEmptyMaps = builder.trimEmptyMaps;
      trimStrings = builder.trimStrings;
      uriContext = builder.uriContext;
      uriRelativity = builder.uriRelativity;
      uriResolution = builder.uriResolution;

      this.producesMediaType = MediaType.of(produces);
      this.acceptRanges = MediaRanges.of(nn(accept) ? accept : produces);
      this.acceptMediaTypes = u(l(nn(builder.accept) ? MediaType.ofAll(splita(builder.accept)) : new MediaType[]{this.producesMediaType}));
   }

   @Override /* Overridden from Context */
   public Builder<?> copy() {
      return new DefaultBuilder(this);
   }

   @Override /* Overridden from Context */
   public SerializerSession.Builder<?> createSession() {
      return SerializerSession.create(this);
   }

   /**
    * Performs an action on the media types handled based on the value of the <c>accept</c> parameter passed into the constructor.
    *
    * <p>
    * The order of the media types are the same as those in the <c>accept</c> parameter.
    *
    * @param action The action to perform on the media types.
    *    <br>Must not be <jk>null</jk>.
    * @return This object.
    */
   public final Serializer forEachAcceptMediaType(Consumer<MediaType> action) {
      for (var m : acceptMediaTypes)
         action.accept(m);
      return this;
   }

   /**
    * Returns the media types handled based on the value of the <c>accept</c> parameter passed into the constructor.
    *
    * <p>
    * Note that the order of these ranges are from high to low q-value.
    *
    * @return The list of media types.  Never <jk>null</jk>.
    */
   public final MediaRanges getMediaTypeRanges() { return acceptRanges; }

   /**
    * Returns the first entry in the <c>accept</c> parameter passed into the constructor.
    *
    * <p>
    * This signifies the 'primary' media type for this serializer.
    *
    * @return The media type.  Never <jk>null</jk>.
    */
   public final MediaType getPrimaryMediaType() { return first(acceptMediaTypes).orElseThrow(() -> new IllegalStateException("No accept media types available")); }

   /**
    * Optional method that returns the response <c>Content-Type</c> for this serializer if it is different from
    * the matched media type.
    *
    * <p>
    * This method is specified to override the content type for this serializer.
    * For example, the {@link Json5Serializer} class returns that it handles media type
    * <js>"text/json5"</js>, but returns <js>"text/json"</js> as the actual content type.
    * This allows clients to request specific 'flavors' of content using specialized <c>Accept</c> header values.
    *
    * <p>
    * This method is typically meaningless if the serializer is being used stand-alone (i.e. outside of a REST server
    * or client).
    *
    * @return The response content type.  If <jk>null</jk>, then the matched media type is used.
    */
   public final MediaType getResponseContentType() { return producesMediaType; }

   /**
    * Optional method that specifies HTTP request headers for this serializer.
    *
    * <p>
    * For example, {@link SoapXmlSerializer} needs to set a <c>SOAPAction</c> header.
    *
    * <p>
    * This method is typically meaningless if the serializer is being used stand-alone (i.e. outside of a REST server
    * or client).
    *
    * @param session The current session.
    * @return
    *    The HTTP headers to set on HTTP requests.
    *    Never <jk>null</jk>.
    */
   public Map<String,String> getResponseHeaders(SerializerSession session) {
      return emptyMap();
   }

   @Override /* Overridden from Context */
   public SerializerSession getSession() { return createSession().build(); }

   /**
    * Returns <jk>true</jk> if this serializer subclasses from {@link WriterSerializer}.
    *
    * @return <jk>true</jk> if this serializer subclasses from {@link WriterSerializer}.
    */
   public boolean isWriterSerializer() { return false; }

   /**
    * Shortcut method for serializing objects directly to either a <c>String</c> or <code><jk>byte</jk>[]</code>
    * depending on the serializer type.
    *
    * @param o The object to serialize.
    * @return
    *    The serialized object.
    *    <br>Character-based serializers will return a <c>String</c>
    *    <br>Stream-based serializers will return a <code><jk>byte</jk>[]</code>
    * @throws SerializeException If a problem occurred trying to convert the output.
    */
   public Object write(Object o) throws SerializeException {
      return getSession().write(o);
   }

   /**
    * Serializes a POJO to the specified output stream or writer.
    *
    * <p>
    * Equivalent to calling <c>serializer.createSession().write(o, output);</c>
    *
    * @param o The object to serialize.
    * @param output
    *    The output object.
    *    <br>Character-based serializers can handle the following output class types:
    *    <ul>
    *       <li>{@link Writer}
    *       <li>{@link OutputStream} - Output will be written as UTF-8 encoded stream.
    *    </ul>
    *    <br>Stream-based serializers can handle the following output class types:
    *    <ul>
    *       <li>{@link OutputStream}
    *    </ul>
    * @throws SerializeException If a problem occurred trying to convert the output.
    * @throws IOException Thrown by the underlying stream.
    */
   public final void write(Object o, Object output) throws SerializeException, IOException {
      getSession().write(o, output);
   }

   /**
    * Convenience method for serializing an object to a String.
    *
    * <p>
    * For writer-based serializers, this is identical to calling {@link #write(Object)}.
    * <br>For stream-based serializers, this converts the returned byte array to a string based on
    * the {@link OutputStreamSerializer.Builder#binaryFormat(BinaryFormat)} setting.
    *
    * @param o The object to serialize.
    * @return The output serialized to a string.
    * @throws SerializeException If a problem occurred trying to convert the output.
    */
   public final String writeToString(Object o) throws SerializeException {
      return getSession().writeToString(o);
   }

   /**
    * Serializes a POJO to the specified pipe.
    *
    * @param session The current session.
    * @param pipe Where to send the output from the serializer.
    * @param o The object to serialize.
    * @throws IOException Thrown by underlying stream.
    * @throws SerializeException Problem occurred trying to serialize object.
    */
   protected void doWrite(SerializerSession session, SerializerPipe pipe, Object o) throws IOException, SerializeException {
      throw uoex();
   }

   /**
    * Serializer listener.
    *
    * @see Serializer.Builder#listener(Class)
    * @return
    *    Class used to listen for errors and warnings that occur during serialization.
    */
   protected final Class<? extends SerializerListener> getListener() { return listener; }

   /**
    * URI context bean.
    *
    * @see Serializer.Builder#uriContext(UriContext)
    * @return
    *    Bean used for resolution of URIs to absolute or root-relative form.
    */
   protected final UriContext getUriContext() { return uriContext; }

   /**
    * URI relativity.
    *
    * @see Serializer.Builder#uriRelativity(UriRelativity)
    * @return
    *    Defines what relative URIs are relative to when serializing any of the following:
    */
   protected final UriRelativity getUriRelativity() { return uriRelativity; }

   /**
    * URI resolution.
    *
    * @see Serializer.Builder#uriResolution(UriResolution)
    * @return
    *    Defines the resolution level for URIs when serializing URIs.
    */
   protected final UriResolution getUriResolution() { return uriResolution; }

   /**
    * Add <js>"_type"</js> properties when needed.
    *
    * @see Serializer.Builder#addBeanTypes()
    * @return
    *    <jk>true</jk> if <js>"_type"</js> properties added to beans if their type cannot be inferred
    *    through reflection.
    */
   protected boolean isAddBeanTypes() { return addBeanTypes; }

   /**
    * Add type attribute to root nodes.
    *
    * @see Serializer.Builder#addRootType()
    * @return
    *    <jk>true</jk> if type property should be added to root node.
    */
   protected final boolean isAddRootType() { return addRootType; }

   /**
    * Don't trim null bean property values.
    *
    * @see Serializer.Builder#keepNullProperties()
    * @return
    *    <jk>true</jk> if null bean values are serialized to the output.
    */
   protected final boolean isKeepNullProperties() { return keepNullProperties; }

   /**
    * Don't serialize bean properties whose values equal the default for their type.
    *
    * @see Serializer.Builder#nonDefault()
    * @return
    *    <jk>true</jk> if bean properties whose value equals the type / bean-constructed default are omitted.
    * @since 10.0.0
    */
   protected final boolean isNonDefault() { return nonDefault; }

   /**
    * Sort arrays and collections alphabetically.
    *
    * @see Serializer.Builder#sortCollections()
    * @return
    *    <jk>true</jk> if arrays and collections are copied and sorted before serialization.
    */
   protected final boolean isSortCollections() { return sortCollections; }

   /**
    * Sort maps alphabetically.
    *
    * @see Serializer.Builder#sortMaps()
    * @return
    *    <jk>true</jk> if maps are copied and sorted before serialization.
    */
   protected final boolean isSortMaps() { return sortMaps; }

   /**
    * Trim empty lists and arrays.
    *
    * @see Serializer.Builder#trimEmptyCollections()
    * @return
    *    <jk>true</jk> if empty lists and arrays are not serialized to the output.
    */
   protected final boolean isTrimEmptyCollections() { return trimEmptyCollections; }

   /**
    * Trim empty maps.
    *
    * @see Serializer.Builder#trimEmptyMaps()
    * @return
    *    <jk>true</jk> if empty map values are not serialized to the output.
    */
   protected final boolean isTrimEmptyMaps() { return trimEmptyMaps; }

   /**
    * Trim strings.
    *
    * @see Serializer.Builder#trimStrings()
    * @return
    *    <jk>true</jk> if string values will be trimmed of whitespace using {@link String#trim()} before being serialized.
    */
   protected final boolean isTrimStrings() { return trimStrings; }

   @Override /* Overridden from MarshallingTraverseContext */
   protected FluentMap<String,Object> properties() {
      return super.properties()
         .a("addBeanTypes", addBeanTypes)
         .a("addRootType", addRootType)
         .a("keepNullProperties", keepNullProperties)
         .a("listener", listener)
         .a("nonDefault", nonDefault)
         .a("sortCollections", sortCollections)
         .a("sortMaps", sortMaps)
         .a("trimEmptyCollections", trimEmptyCollections)
         .a("trimEmptyMaps", trimEmptyMaps)
         .a("trimStrings", trimStrings)
         .a("uriContext", uriContext)
         .a("uriRelativity", uriRelativity)
         .a("uriResolution", uriResolution);
   }
}