/*
 * 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.xml;

import static org.apache.juneau.commons.utils.AssertionUtils.*;
import static org.apache.juneau.commons.utils.CollectionUtils.*;
import static org.apache.juneau.commons.utils.Utils.*;

import java.lang.annotation.*;
import java.nio.charset.*;
import java.util.*;
import java.util.concurrent.*;

import org.apache.juneau.*;
import org.apache.juneau.commons.collections.*;
import org.apache.juneau.commons.function.*;
import org.apache.juneau.commons.reflect.*;
import org.apache.juneau.json.*;
import org.apache.juneau.serializer.*;

/**
 * Serializes POJO models to XML.
 *
 * <h5 class='topic'>Media types</h5>
 * <p>
 * Handles <c>Accept</c> types:  <bc>text/xml</bc>
 * <p>
 * Produces <c>Content-Type</c> types:  <bc>text/xml</bc>
 *
 * <h5 class='topic'>Description</h5>
 * <p>
 * See the {@link JsonSerializer} class for details on how Java models map to JSON.
 *
 * <p>
 * For example, the following JSON...
 * <p class='bjson'>
 *    {
 *       name:<js>'John Smith'</js>,
 *       address: {
 *          streetAddress: <js>'21 2nd Street'</js>,
 *          city: <js>'New York'</js>,
 *          state: <js>'NY'</js>,
 *          postalCode: <js>10021</js>
 *       },
 *       phoneNumbers: [
 *          <js>'212 555-1111'</js>,
 *          <js>'212 555-2222'</js>
 *       ],
 *       additionalInfo: <jk>null</jk>,
 *       remote: <jk>false</jk>,
 *       height: <js>62.4</js>,
 *       <js>'fico score'</js>:  <js>' &gt; 640'</js>
 *    }
 * <p>
 *    ...maps to the following XML using the default serializer...
 * <p class='bxml'>
 *    <xt>&lt;object&gt;</xt>
 *       <xt>&lt;name&gt;</xt>John Smith<xt>&lt;/name&gt;</xt>
 *       <xt>&lt;address&gt;</xt>
 *          <xt>&lt;streetAddress&gt;</xt>21 2nd Street<xt>&lt;/streetAddress&gt;</xt>
 *          <xt>&lt;city&gt;</xt>New York<xt>&lt;/city&gt;</xt>
 *          <xt>&lt;state&gt;</xt>NY<xt>&lt;/state&gt;</xt>
 *          <xt>&lt;postalCode&gt;</xt>10021<xt>&lt;/postalCode&gt;</xt>
 *       <xt>&lt;/address&gt;</xt>
 *       <xt>&lt;phoneNumbers&gt;</xt>
 *          <xt>&lt;string&gt;</xt>212 555-1111<xt>&lt;/string&gt;</xt>
 *          <xt>&lt;string&gt;</xt>212 555-2222<xt>&lt;/string&gt;</xt>
 *       <xt>&lt;/phoneNumbers&gt;</xt>
 *       <xt>&lt;additionalInfo</xt> <xa>_type</xa>=<xs>'null'</xs><xt>&gt;&lt;/additionalInfo&gt;</xt>
 *       <xt>&lt;remote&gt;</xt>false<xt>&lt;/remote&gt;</xt>
 *       <xt>&lt;height&gt;</xt>62.4<xt>&lt;/height&gt;</xt>
 *       <xt>&lt;fico_x0020_score&gt;</xt> &amp;gt; 640<xt>&lt;/fico_x0020_score&gt;</xt>
 *    <xt>&lt;/object&gt;</xt>
 *
 * <p>
 * An additional "add-json-properties" mode is also provided to prevent loss of JSON data types...
 * <p class='bxml'>
 *    <xt>&lt;object&gt;</xt>
 *       <xt>&lt;name</xt> <xa>_type</xa>=<xs>'string'</xs><xt>&gt;</xt>John Smith<xt>&lt;/name&gt;</xt>
 *       <xt>&lt;address</xt> <xa>_type</xa>=<xs>'object'</xs><xt>&gt;</xt>
 *          <xt>&lt;streetAddress</xt> <xa>_type</xa>=<xs>'string'</xs><xt>&gt;</xt>21 2nd Street<xt>&lt;/streetAddress&gt;</xt>
 *          <xt>&lt;city</xt> <xa>_type</xa>=<xs>'string'</xs><xt>&gt;</xt>New York<xt>&lt;/city&gt;</xt>
 *          <xt>&lt;state</xt> <xa>_type</xa>=<xs>'string'</xs><xt>&gt;</xt>NY<xt>&lt;/state&gt;</xt>
 *          <xt>&lt;postalCode</xt> <xa>_type</xa>=<xs>'number'</xs><xt>&gt;</xt>10021<xt>&lt;/postalCode&gt;</xt>
 *       <xt>&lt;/address&gt;</xt>
 *       <xt>&lt;phoneNumbers</xt> <xa>_type</xa>=<xs>'array'</xs><xt>&gt;</xt>
 *          <xt>&lt;string&gt;</xt>212 555-1111<xt>&lt;/string&gt;</xt>
 *          <xt>&lt;string&gt;</xt>212 555-2222<xt>&lt;/string&gt;</xt>
 *       <xt>&lt;/phoneNumbers&gt;</xt>
 *       <xt>&lt;additionalInfo</xt> <xa>_type</xa>=<xs>'null'</xs><xt>&gt;&lt;/additionalInfo&gt;</xt>
 *       <xt>&lt;remote</xt> <xa>_type</xa>=<xs>'boolean'</xs><xt>&gt;</xt>false<xt>&lt;/remote&gt;</xt>
 *       <xt>&lt;height</xt> <xa>_type</xa>=<xs>'number'</xs><xt>&gt;</xt>62.4<xt>&lt;/height&gt;</xt>
 *       <xt>&lt;fico_x0020_score</xt> <xa>_type</xa>=<xs>'string'</xs><xt>&gt;</xt> &amp;gt; 640<xt>&lt;/fico_x0020_score&gt;</xt>
 *    <xt>&lt;/object&gt;</xt>
 * </p>
 *
 * <p>
 * This serializer provides several serialization options.
 * Typically, one of the predefined <jsf>DEFAULT</jsf> serializers will be sufficient.
 * However, custom serializers can be constructed to fine-tune behavior.
 *
 * <p>
 * If an attribute name contains any non-valid XML element characters, they will be escaped using standard
 * {@code _x####_} notation.
 *
 * <h5 class='topic'>Behavior-specific subclasses</h5>
 * <p>
 * The following direct subclasses are provided for convenience:
 * <ul>
 *    <li>{@link Sq} - Default serializer, single quotes.
 *    <li>{@link SqReadable} - Default serializer, single quotes, whitespace added.
 * </ul>
 *
 * <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/XmlBasics">XML Basics</a>

 * </ul>
 */
public class XmlSerializer extends WriterSerializer implements XmlMetaProvider {
   /**
    * Builder class.
    */
   public static class Builder extends WriterSerializer.Builder {

      private static final Cache<HashKey,XmlSerializer> CACHE = Cache.of(HashKey.class, XmlSerializer.class).build();

      private boolean addBeanTypesXml;
      private boolean addNamespaceUrisToRoot;
      private boolean disableAutoDetectNamespaces;
      private boolean disableJsonTags;
      private boolean enableNamespaces;
      private Namespace defaultNamespace;
      private List<Namespace> namespaces;
      private String textNodeDelimiter;

      /**
       * Constructor, default settings.
       */
      protected Builder() {
         produces("text/xml");
         addBeanTypesXml = env("XmlSerializer.addBeanTypes", false);
         addNamespaceUrisToRoot = env("XmlSerializer.addNamespaceUrisToRoot", false);
         disableAutoDetectNamespaces = env("XmlSerializer.disableAutoDetectNamespaces", false);
         disableJsonTags = env("XmlSerializer.disableJsonTags", false);
         enableNamespaces = env("XmlSerializer.enableNamespaces", false);
         defaultNamespace = null;
         namespaces = null;
         textNodeDelimiter = env("XmlSerializer.textNodeDelimiter", "");
      }

      /**
       * Copy constructor.
       *
       * @param copyFrom The builder to copy from.
       *    <br>Cannot be <jk>null</jk>.
       */
      protected Builder(Builder copyFrom) {
         super(assertArgNotNull("copyFrom", copyFrom));
         addBeanTypesXml = copyFrom.addBeanTypesXml;
         addNamespaceUrisToRoot = copyFrom.addNamespaceUrisToRoot;
         defaultNamespace = copyFrom.defaultNamespace;
         disableAutoDetectNamespaces = copyFrom.disableAutoDetectNamespaces;
         disableJsonTags = copyFrom.disableJsonTags;
         enableNamespaces = copyFrom.enableNamespaces;
         namespaces = copyFrom.namespaces == null ? null : new ArrayList<>(copyFrom.namespaces);
         textNodeDelimiter = copyFrom.textNodeDelimiter;
      }

      /**
       * Copy constructor.
       *
       * @param copyFrom The bean to copy from.
       *    <br>Cannot be <jk>null</jk>.
       */
      protected Builder(XmlSerializer copyFrom) {
         super(assertArgNotNull("copyFrom", copyFrom));
         addBeanTypesXml = copyFrom.addBeanTypesXml;
         addNamespaceUrisToRoot = copyFrom.addNamespaceUrlsToRoot;
         defaultNamespace = copyFrom.getDefaultNamespace();
         disableAutoDetectNamespaces = ! copyFrom.autoDetectNamespaces;
         disableJsonTags = ! copyFrom.addJsonTags;
         enableNamespaces = copyFrom.enableNamespaces;
         var ctxNamespaces = copyFrom.getNamespaces();
         namespaces = ctxNamespaces.isEmpty() ? null : new ArrayList<>(ctxNamespaces);
         textNodeDelimiter = copyFrom.getTextNodeDelimiter();
      }

      @Override /* Overridden from Builder */
      public Builder accept(String value) {
         super.accept(value);
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder addBeanTypes() {
         super.addBeanTypes();
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder addBeanTypes(boolean value) {
         super.addBeanTypes(value);
         return this;
      }

      /**
       * Add <js>"_type"</js> properties when needed.
       *
       * <p>
       * If <jk>true</jk>, then <js>"_type"</js> properties will be added to beans if their type cannot be inferred
       * through reflection.
       *
       * <p>
       * When present, this value overrides the {@link org.apache.juneau.serializer.Serializer.Builder#addBeanTypes()} setting and is
       * provided to customize the behavior of specific serializers in a {@link SerializerSet}.
       *
       * @return This object.
       */
      public Builder addBeanTypesXml() {
         return addBeanTypesXml(true);
      }

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

      /**
       * Add namespace URLs to the root element.
       *
       * <p>
       * Use this setting to add {@code xmlns:x} attributes to the root element for the default and all mapped namespaces.
       *
       * <p>
       * This setting is ignored if {@link #enableNamespaces()} is not enabled.
       *
       * <h5 class='section'>See Also:</h5><ul>
       *    <li class='link'><a class="doclink" href="https://juneau.apache.org/docs/topics/XmlNamespaces">Namespaces</a>
       * </ul>
       *
       * @return This object.
       */
      public Builder addNamespaceUrisToRoot() {
         return addNamespaceUrisToRoot(true);
      }

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

      @Override /* Overridden from Builder */
      public Builder addRootType() {
         super.addRootType();
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder addRootType(boolean value) {
         super.addRootType(value);
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder annotations(Annotation...values) {
         super.annotations(values);
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder apply(AnnotationWorkList work) {
         super.apply(work);
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder applyAnnotations(Class<?>...from) {
         super.applyAnnotations(from);
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder applyAnnotations(Object...from) {
         super.applyAnnotations(from);
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder beanClassVisibility(Visibility value) {
         super.beanClassVisibility(value);
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder beanConstructorVisibility(Visibility value) {
         super.beanConstructorVisibility(value);
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder beanContext(BeanContext value) {
         super.beanContext(value);
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder beanContext(BeanContext.Builder value) {
         super.beanContext(value);
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder beanDictionary(java.lang.Class<?>...values) {
         super.beanDictionary(values);
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder beanFieldVisibility(Visibility value) {
         super.beanFieldVisibility(value);
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder beanInterceptor(Class<?> on, Class<? extends org.apache.juneau.swap.BeanInterceptor<?>> value) {
         super.beanInterceptor(on, value);
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder beanMapPutReturnsOldValue() {
         super.beanMapPutReturnsOldValue();
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder beanMethodVisibility(Visibility value) {
         super.beanMethodVisibility(value);
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder beanProperties(Class<?> beanClass, String properties) {
         super.beanProperties(beanClass, properties);
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder beanProperties(Map<String,Object> values) {
         super.beanProperties(values);
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder beanProperties(String beanClassName, String properties) {
         super.beanProperties(beanClassName, properties);
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder beanPropertiesExcludes(Class<?> beanClass, String properties) {
         super.beanPropertiesExcludes(beanClass, properties);
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder beanPropertiesExcludes(Map<String,Object> values) {
         super.beanPropertiesExcludes(values);
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder beanPropertiesExcludes(String beanClassName, String properties) {
         super.beanPropertiesExcludes(beanClassName, properties);
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder beanPropertiesReadOnly(Class<?> beanClass, String properties) {
         super.beanPropertiesReadOnly(beanClass, properties);
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder beanPropertiesReadOnly(Map<String,Object> values) {
         super.beanPropertiesReadOnly(values);
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder beanPropertiesReadOnly(String beanClassName, String properties) {
         super.beanPropertiesReadOnly(beanClassName, properties);
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder beanPropertiesWriteOnly(Class<?> beanClass, String properties) {
         super.beanPropertiesWriteOnly(beanClass, properties);
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder beanPropertiesWriteOnly(Map<String,Object> values) {
         super.beanPropertiesWriteOnly(values);
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder beanPropertiesWriteOnly(String beanClassName, String properties) {
         super.beanPropertiesWriteOnly(beanClassName, properties);
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder beansRequireDefaultConstructor() {
         super.beansRequireDefaultConstructor();
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder beansRequireSerializable() {
         super.beansRequireSerializable();
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder beansRequireSettersForGetters() {
         super.beansRequireSettersForGetters();
         return this;
      }

      @Override /* Overridden from Context.Builder */
      public XmlSerializer build() {
         return cache(CACHE).build(XmlSerializer.class);
      }

      @Override /* Overridden from Builder */
      public Builder cache(Cache<HashKey,? extends org.apache.juneau.Context> value) {
         super.cache(value);
         return this;
      }

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

      @Override /* Overridden from Builder */
      public Builder debug() {
         super.debug();
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder debug(boolean value) {
         super.debug(value);
         return this;
      }

      /**
       * Default namespace.
       *
       * <p>
       * Specifies the default namespace URI for this document.
       *
       * <h5 class='section'>See Also:</h5><ul>
       *    <li class='link'><a class="doclink" href="https://juneau.apache.org/docs/topics/XmlNamespaces">Namespaces</a>
       * </ul>
       *
       * @param value
       *    The new value for this property.
       *    <br>The default is <js>"juneau: http://www.apache.org/2013/Juneau"</js>.
       *    <br>Can be <jk>null</jk> to specify no namespace.
       * @return This object.
       */
      public Builder defaultNamespace(Namespace value) {
         defaultNamespace = value;
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder detectRecursions() {
         super.detectRecursions();
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder detectRecursions(boolean value) {
         super.detectRecursions(value);
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder dictionaryOn(Class<?> on, java.lang.Class<?>...values) {
         super.dictionaryOn(on, values);
         return this;
      }

      /**
       * Don't auto-detect namespace usage.
       *
       * <p>
       * Don't detect namespace usage before serialization.
       *
       * <p>
       * Used in conjunction with {@link Builder#addNamespaceUrisToRoot()} to reduce the list of namespace URLs appended to the
       * root element to only those that will be used in the resulting document.
       *
       * <p>
       * If disabled, then the data structure will first be crawled looking for namespaces that will be encountered before
       * the root element is serialized.
       *
       * <p>
       * This setting is ignored if {@link Builder#enableNamespaces()} is not enabled.
       *
       * <h5 class='section'>Notes:</h5><ul>
       *    <li class='note'>
       *       Auto-detection of namespaces can be costly performance-wise.
       *       <br>In high-performance environments, it's recommended that namespace detection be
       *       disabled, and that namespaces be manually defined through the {@link Builder#namespaces(Namespace...)} property.
       * </ul>
       *
       * <h5 class='section'>See Also:</h5><ul>
       *    <li class='link'><a class="doclink" href="https://juneau.apache.org/docs/topics/XmlNamespaces">Namespaces</a>
       * </ul>
       *
       * @return This object.
       */
      public Builder disableAutoDetectNamespaces() {
         return disableAutoDetectNamespaces(true);
      }

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

      @Override /* Overridden from Builder */
      public Builder disableBeansRequireSomeProperties() {
         super.disableBeansRequireSomeProperties();
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder disableIgnoreMissingSetters() {
         super.disableIgnoreMissingSetters();
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder disableIgnoreTransientFields() {
         super.disableIgnoreTransientFields();
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder disableIgnoreUnknownNullBeanProperties() {
         super.disableIgnoreUnknownNullBeanProperties();
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder disableInterfaceProxies() {
         super.disableInterfaceProxies();
         return this;
      }

      /**
       * <i><l>XmlSerializer</l> configuration property:&emsp;</i>  Disable use of JSON type identifier tags.
       *
       * <p>
       * When enabled, JSON type tags (e.g. <js>"&lt;string&gt;"</js>) tags and attributes will not be added to the output.
       * Note that JSON type tags are used to ensure parsers are able to recreate the original data types passed
       * into the serializer.  Disabling JSON tags can cause different data to be parsed (e.g. strings instead of numbers).
       *
       * @return This object.
       */
      public Builder disableJsonTags() {
         return disableJsonTags(true);
      }

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

      /**
       * Enable support for XML namespaces.
       *
       * <p>
       * If not enabled, XML output will not contain any namespaces regardless of any other settings.
       *
       * <h5 class='section'>See Also:</h5><ul>
       *    <li class='link'><a class="doclink" href="https://juneau.apache.org/docs/topics/XmlNamespaces">Namespaces</a>
       * </ul>
       *
       * @return This object.
       */
      public Builder enableNamespaces() {
         return enableNamespaces(true);
      }

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

      @Override /* Overridden from Builder */
      public <T> Builder example(Class<T> pojoClass, String json) {
         super.example(pojoClass, json);
         return this;
      }

      @Override /* Overridden from Builder */
      public <T> Builder example(Class<T> pojoClass, T o) {
         super.example(pojoClass, o);
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder fileCharset(Charset value) {
         super.fileCharset(value);
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder findFluentSetters() {
         super.findFluentSetters();
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder findFluentSetters(Class<?> on) {
         super.findFluentSetters(on);
         return this;
      }

      @Override /* Overridden from Context.Builder */
      public HashKey hashKey() {
         // @formatter:off
         return HashKey.of(
            super.hashKey(),
            addBeanTypesXml,
            addNamespaceUrisToRoot,
            disableAutoDetectNamespaces,
            disableJsonTags,
            enableNamespaces,
            defaultNamespace,
            namespaces,
            textNodeDelimiter
         );
         // @formatter:on
      }

      @Override /* Overridden from Builder */
      public Builder ignoreInvocationExceptionsOnGetters() {
         super.ignoreInvocationExceptionsOnGetters();
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder ignoreInvocationExceptionsOnSetters() {
         super.ignoreInvocationExceptionsOnSetters();
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder ignoreRecursions() {
         super.ignoreRecursions();
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder ignoreRecursions(boolean value) {
         super.ignoreRecursions(value);
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder ignoreUnknownBeanProperties() {
         super.ignoreUnknownBeanProperties();
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder ignoreUnknownEnumValues() {
         super.ignoreUnknownEnumValues();
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder impl(Context value) {
         super.impl(value);
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder implClass(Class<?> interfaceClass, Class<?> implClass) {
         super.implClass(interfaceClass, implClass);
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder implClasses(Map<Class<?>,Class<?>> values) {
         super.implClasses(values);
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder initialDepth(int value) {
         super.initialDepth(value);
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder interfaceClass(Class<?> on, Class<?> value) {
         super.interfaceClass(on, value);
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder interfaces(java.lang.Class<?>...value) {
         super.interfaces(value);
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder keepNullProperties() {
         super.keepNullProperties();
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder keepNullProperties(boolean value) {
         super.keepNullProperties(value);
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder listener(Class<? extends org.apache.juneau.serializer.SerializerListener> value) {
         super.listener(value);
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder locale(Locale value) {
         super.locale(value);
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder maxDepth(int value) {
         super.maxDepth(value);
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder maxIndent(int value) {
         super.maxIndent(value);
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder mediaType(MediaType value) {
         super.mediaType(value);
         return this;
      }

      /**
       * Default namespaces.
       *
       * <p>
       * The default list of namespaces associated with this serializer.
       *
       * @param values The new value for this property.
       *    <br>Cannot contain <jk>null</jk> values.
       * @return This object.
       */
      public Builder namespaces(Namespace...values) {
         assertArgNoNulls("values", values);
         namespaces = addAll(namespaces, values);
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder notBeanClasses(java.lang.Class<?>...values) {
         super.notBeanClasses(values);
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder notBeanPackages(String...values) {
         super.notBeanPackages(values);
         return this;
      }

      /**
       * Enable support for XML namespaces.
       *
       * <p>
       * Shortcut for calling <code>enableNamespaces(<jk>true</jk>)</code>.
       *
       * @return This object.
       */
      public Builder ns() {
         return enableNamespaces();
      }

      @Override /* Overridden from Builder */
      public Builder produces(String value) {
         super.produces(value);
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder propertyNamer(Class<?> on, Class<? extends org.apache.juneau.PropertyNamer> value) {
         super.propertyNamer(on, value);
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder propertyNamer(Class<? extends org.apache.juneau.PropertyNamer> value) {
         super.propertyNamer(value);
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder quoteChar(char value) {
         super.quoteChar(value);
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder quoteCharOverride(char value) {
         super.quoteCharOverride(value);
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder sortCollections() {
         super.sortCollections();
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder sortCollections(boolean value) {
         super.sortCollections(value);
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder sortMaps() {
         super.sortMaps();
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder sortMaps(boolean value) {
         super.sortMaps(value);
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder sortProperties() {
         super.sortProperties();
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder sortProperties(java.lang.Class<?>...on) {
         super.sortProperties(on);
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder sq() {
         super.sq();
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder stopClass(Class<?> on, Class<?> value) {
         super.stopClass(on, value);
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder streamCharset(Charset value) {
         super.streamCharset(value);
         return this;
      }

      @Override /* Overridden from Builder */
      public <T,S> Builder swap(Class<T> normalClass, Class<S> swappedClass, ThrowingFunction<T,S> swapFunction) {
         super.swap(normalClass, swappedClass, swapFunction);
         return this;
      }

      @Override /* Overridden from Builder */
      public <T,S> Builder swap(Class<T> normalClass, Class<S> swappedClass, ThrowingFunction<T,S> swapFunction, ThrowingFunction<S,T> unswapFunction) {
         super.swap(normalClass, swappedClass, swapFunction, unswapFunction);
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder swaps(Class<?>...values) {
         super.swaps(values);
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder swaps(Object...values) {
         super.swaps(values);
         return this;
      }

      /**
       * Text node delimiter.
       *
       * <p>
       * Specifies the delimiter string to insert between consecutive text nodes.
       * This is useful for adding spacing between text elements to improve readability.
       *
       * <p>
       * The default value is an empty string (no delimiter).
       *
       * <h5 class='section'>Example:</h5>
       * <p class='bjava'>
       *    XmlSerializer.<jsm>create</jsm>()
       *       .textNodeDelimiter(<js>" "</js>)
       *       .build();
       * </p>
       *
       * <p>
       * With this setting, serializing:
       * <p class='bjava'>
       *    <jk>new</jk> Audio().children(<js>"a"</js>, <js>"b"</js>, <jk>new</jk> Strong(<js>"c"</js>));
       * </p>
       *
       * <p>
       * Will produce: <code>&lt;audio&gt;a b&lt;strong&gt;c&lt;/strong&gt;&lt;/audio&gt;</code>
       * <br>Instead of: <code>&lt;audio&gt;ab&lt;strong&gt;c&lt;/strong&gt;&lt;/audio&gt;</code>
       *
       * @param value
       *    The delimiter string.
       *    <br>Can be <jk>null</jk> (interpreted as empty string).
       * @return This object.
       */
      public Builder textNodeDelimiter(String value) {
         textNodeDelimiter = value == null ? "" : value;
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder timeZone(TimeZone value) {
         super.timeZone(value);
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder trimEmptyCollections() {
         super.trimEmptyCollections();
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder trimEmptyCollections(boolean value) {
         super.trimEmptyCollections(value);
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder trimEmptyMaps() {
         super.trimEmptyMaps();
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder trimEmptyMaps(boolean value) {
         super.trimEmptyMaps(value);
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder trimStrings() {
         super.trimStrings();
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder trimStrings(boolean value) {
         super.trimStrings(value);
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder type(Class<? extends org.apache.juneau.Context> value) {
         super.type(value);
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder typeName(Class<?> on, String value) {
         super.typeName(on, value);
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder typePropertyName(Class<?> on, String value) {
         super.typePropertyName(on, value);
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder typePropertyName(String value) {
         super.typePropertyName(value);
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder uriContext(UriContext value) {
         super.uriContext(value);
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder uriRelativity(UriRelativity value) {
         super.uriRelativity(value);
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder uriResolution(UriResolution value) {
         super.uriResolution(value);
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder useEnumNames() {
         super.useEnumNames();
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder useJavaBeanIntrospector() {
         super.useJavaBeanIntrospector();
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder useWhitespace() {
         super.useWhitespace();
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder useWhitespace(boolean value) {
         super.useWhitespace(value);
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder ws() {
         super.ws();
         return this;
      }
   }

   /** Default serializer without namespaces. */
   public static class Ns extends XmlSerializer {

      /**
       * Constructor.
       *
       * @param builder The builder for this object.
       *    <br>Cannot be <jk>null</jk>.
       */
      public Ns(Builder builder) {
         super(assertArgNotNull("builder", builder).enableNamespaces());
      }
   }

   /** Default serializer without namespaces, single quotes. */
   public static class NsSq extends XmlSerializer {

      /**
       * Constructor.
       *
       * @param builder The builder for this object.
       *    <br>Cannot be <jk>null</jk>.
       */
      public NsSq(Builder builder) {
         super(assertArgNotNull("builder", builder).enableNamespaces().quoteChar('\''));
      }
   }

   /** Default serializer without namespaces, single quotes, with whitespace. */
   public static class NsSqReadable extends XmlSerializer {

      /**
       * Constructor.
       *
       * @param builder The builder for this object.
       *    <br>Cannot be <jk>null</jk>.
       */
      public NsSqReadable(Builder builder) {
         super(assertArgNotNull("builder", builder).enableNamespaces().quoteChar('\'').useWhitespace());
      }
   }

   /** Default serializer, single quotes. */
   public static class Sq extends XmlSerializer {

      /**
       * Constructor.
       *
       * @param builder The builder for this object.
       *    <br>Cannot be <jk>null</jk>.
       */
      public Sq(Builder builder) {
         super(assertArgNotNull("builder", builder).quoteChar('\''));
      }
   }

   /** Default serializer, single quotes, whitespace added. */
   public static class SqReadable extends XmlSerializer {

      /**
       * Constructor.
       *
       * @param builder The builder for this object.
       *    <br>Cannot be <jk>null</jk>.
       */
      public SqReadable(Builder builder) {
         super(assertArgNotNull("builder", builder).quoteChar('\'').useWhitespace());
      }
   }


   /** Default serializer without namespaces. */
   public static final XmlSerializer DEFAULT = new XmlSerializer(create());
   /** Default serializer without namespaces, with single quotes. */
   public static final XmlSerializer DEFAULT_SQ = new Sq(create());

   /** Default serializer without namespaces, with single quotes, whitespace added. */
   public static final XmlSerializer DEFAULT_SQ_READABLE = new SqReadable(create());

   /** Default serializer, all default settings. */
   public static final XmlSerializer DEFAULT_NS = new Ns(create());

   /** Default serializer, single quotes. */
   public static final XmlSerializer DEFAULT_NS_SQ = new NsSq(create());

   /** Default serializer, single quotes, whitespace added. */
   public static final XmlSerializer DEFAULT_NS_SQ_READABLE = new NsSqReadable(create());

   protected static final Namespace DEFAULT_JUNEAU_NAMESPACE = Namespace.of("juneau", "http://www.apache.org/2013/Juneau"),
      DEFAULT_XS_NAMESPACE = Namespace.of("xs", "http://www.w3.org/2001/XMLSchema");

   /**
    * Creates a new builder for this object.
    *
    * @return A new builder.
    */
   public static Builder create() {
      return new Builder();
   }

   protected final boolean addBeanTypesXml;
   protected final boolean addJsonTags;
   protected final boolean addNamespaceUrlsToRoot;
   protected final boolean autoDetectNamespaces;
   protected final boolean enableNamespaces;
   private final Namespace defaultNamespace;
   private final List<Namespace> namespaces;
   private final String textNodeDelimiter;

   private final boolean addBeanTypes;
   private final Map<ClassMeta<?>,XmlClassMeta> xmlClassMetas = new ConcurrentHashMap<>();
   private final Map<BeanMeta<?>,XmlBeanMeta> xmlBeanMetas = new ConcurrentHashMap<>();
   private final Map<BeanPropertyMeta,XmlBeanPropertyMeta> xmlBeanPropertyMetas = new ConcurrentHashMap<>();

   /**
    * Constructor.
    *
    * @param builder
    *    The builder for this object.
    */
   public XmlSerializer(Builder builder) {
      super(builder);
      addBeanTypesXml = builder.addBeanTypesXml;
      addJsonTags = ! builder.disableJsonTags;
      addNamespaceUrlsToRoot = builder.addNamespaceUrisToRoot;
      autoDetectNamespaces = ! builder.disableAutoDetectNamespaces;
      defaultNamespace = nn(builder.defaultNamespace) ? builder.defaultNamespace : DEFAULT_JUNEAU_NAMESPACE;
      enableNamespaces = builder.enableNamespaces;
      namespaces = u(nn(builder.namespaces) ? new ArrayList<>(builder.namespaces) : new ArrayList<>());
      textNodeDelimiter = builder.textNodeDelimiter;
      addBeanTypes = addBeanTypesXml || super.isAddBeanTypes();
   }

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

   @Override /* Overridden from Context */
   public XmlSerializerSession.Builder createSession() {
      return XmlSerializerSession.create(this);
   }

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

   @Override /* Overridden from XmlMetaProvider */
   public XmlBeanMeta getXmlBeanMeta(BeanMeta<?> bm) {
      XmlBeanMeta m = xmlBeanMetas.get(bm);
      if (m == null) {
         m = new XmlBeanMeta(bm, this);
         xmlBeanMetas.put(bm, m);
      }
      return m;
   }

   @Override /* Overridden from XmlMetaProvider */
   public XmlBeanPropertyMeta getXmlBeanPropertyMeta(BeanPropertyMeta bpm) {
      XmlBeanPropertyMeta m = xmlBeanPropertyMetas.get(bpm);
      if (m == null) {
         m = new XmlBeanPropertyMeta(bpm.getDelegateFor(), this);
         xmlBeanPropertyMetas.put(bpm, m);
      }
      return m;
   }

   @Override /* Overridden from XmlMetaProvider */
   public XmlClassMeta getXmlClassMeta(ClassMeta<?> cm) {
      XmlClassMeta m = xmlClassMetas.get(cm);
      if (m == null) {
         m = new XmlClassMeta(cm, this);
         xmlClassMetas.put(cm, m);
      }
      return m;
   }

   /**
    * Default namespace.
    *
    * @see Builder#defaultNamespace(Namespace)
    * @return
    *    The default namespace URI for this document.
    */
   protected final Namespace getDefaultNamespace() { return defaultNamespace; }

   /**
    * Default namespaces.
    *
    * @see Builder#namespaces(Namespace...)
    * @return
    *    The default list of namespaces associated with this serializer.
    *    <br>Never <jk>null</jk>.
    *    <br>List is unmodifiable.
    */
   protected final List<Namespace> getNamespaces() { return namespaces; }

   /**
    * Text node delimiter.
    *
    * @see Builder#textNodeDelimiter(String)
    * @return
    *    The delimiter string to insert between consecutive text nodes.
    *    <br>Never <jk>null</jk>.
    */
   protected final String getTextNodeDelimiter() { return textNodeDelimiter; }

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

   /**
    * Add namespace URLs to the root element.
    *
    * @see Builder#addNamespaceUrisToRoot()
    * @return
    *    <jk>true</jk> if {@code xmlns:x} attributes are added to the root element for the default and all mapped namespaces.
    */
   protected final boolean isAddNamespaceUrlsToRoot() { return addNamespaceUrlsToRoot; }

   /**
    * Auto-detect namespace usage.
    *
    * @see Builder#disableAutoDetectNamespaces()
    * @return
    *    <jk>true</jk> if namespace usage is detected before serialization.
    */
   protected final boolean isAutoDetectNamespaces() { return autoDetectNamespaces; }

   /**
    * Enable support for XML namespaces.
    *
    * @see Builder#enableNamespaces()
    * @return
    *    <jk>false</jk> if XML output will not contain any namespaces regardless of any other settings.
    */
   protected final boolean isEnableNamespaces() { return enableNamespaces; }

   @Override /* Overridden from WriterSerializer */
   protected FluentMap<String,Object> properties() {
      return super.properties()
         .a("addBeanTypes", addBeanTypes)
         .a("addNamespaceUrlsToRoot", addNamespaceUrlsToRoot)
         .a("autoDetectNamespaces", autoDetectNamespaces)
         .a("defaultNamespace", defaultNamespace)
         .a("enableNamespaces", enableNamespaces)
         .a("namespaces", namespaces);
   }
}