/*
 * 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.serializer;

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

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

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.*;

/**
 * Subclass of {@link Serializer} for character-based serializers.
 *
 * <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>
 */
public class WriterSerializer extends Serializer {
   /**
    * Builder class.
    */
   public static class Builder extends Serializer.Builder {

      private boolean useWhitespace;
      private Character quoteChar;
      private Character quoteCharOverride;
      private Charset fileCharset;
      private Charset streamCharset;
      private int maxIndent;

      /**
       * Constructor, default settings.
       */
      protected Builder() {
         fileCharset = Charset.defaultCharset();
         streamCharset = UTF8;
         maxIndent = env("WriterSerializer.maxIndent", 100);
         quoteChar = env("WriterSerializer.quoteChar").map(x -> (x.length() > 0 ? x.charAt(0) : null)).orElse(null);
         quoteCharOverride = env("WriterSerializer.quoteCharOverride").map(x -> (x.length() > 0 ? x.charAt(0) : null)).orElse(null);
         useWhitespace = env("WriterSerializer.useWhitespace", false);
      }

      /**
       * Copy constructor.
       *
       * @param copyFrom The builder to copy from.
       *    <br>Cannot be <jk>null</jk>.
       */
      protected Builder(Builder copyFrom) {
         super(assertArgNotNull("copyFrom", copyFrom));
         fileCharset = copyFrom.fileCharset;
         streamCharset = copyFrom.streamCharset;
         maxIndent = copyFrom.maxIndent;
         quoteChar = copyFrom.quoteChar;
         quoteCharOverride = copyFrom.quoteCharOverride;
         useWhitespace = copyFrom.useWhitespace;
      }

      /**
       * Copy constructor.
       *
       * @param copyFrom The bean to copy from.
       *    <br>Cannot be <jk>null</jk>.
       */
      protected Builder(WriterSerializer copyFrom) {
         super(assertArgNotNull("copyFrom", copyFrom));
         fileCharset = copyFrom.getFileCharset();
         streamCharset = copyFrom.getStreamCharset();
         maxIndent = copyFrom.maxIndent;
         quoteChar = copyFrom.quoteChar;
         quoteCharOverride = copyFrom.quoteCharOverride;
         useWhitespace = copyFrom.useWhitespace;
      }

      @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;
      }

      @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 WriterSerializer build() {
         return build(WriterSerializer.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;
      }

      @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;
      }

      @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;
      }

      @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;
      }

      /**
       * File charset.
       *
       * <p>
       * The character set to use for writing <c>Files</c> to the file system.
       *
       * <p>
       * Used when passing in files to {@link Serializer#serialize(Object, Object)}.
       *
       * <h5 class='section'>Example:</h5>
       * <p class='bjava'>
       *    <jc>// Create a serializer that writes UTF-8 files.</jc>
       *    WriterSerializer <jv>serializer</jv> = JsonSerializer
       *       .<jsm>create</jsm>()
       *       .fileCharset(Charset.<jsm>forName</jsm>(<js>"UTF-8"</js>))
       *       .build();
       *
       *    <jc>// Use it to read a UTF-8 encoded file.</jc>
       *    <jv>serializer</jv>.serialize(<jk>new</jk> File(<js>"MyBean.txt"</js>), <jv>myBean</jv>);
       * </p>
       *
       * @param value
       *    The new value for this property.
       *    <br>The default is the system JVM setting.
       *    <br>Can be <jk>null</jk> (defaults to system default).
       * @return This object.
       */
      public Builder fileCharset(Charset value) {
         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(),
            fileCharset,
            streamCharset,
            maxIndent,
            quoteChar,
            quoteCharOverride,
            useWhitespace
         );
         // @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;
      }

      /**
       * Maximum indentation.
       *
       * <p>
       * Specifies the maximum indentation level in the serialized document.
       *
       * <h5 class='section'>Notes:</h5><ul>
       *    <li class='note'>This setting does not apply to the RDF serializers.
       * </ul>
       *
       * <h5 class='section'>Example:</h5>
       * <p class='bjava'>
       *    <jc>// Create a serializer that indents a maximum of 20 tabs.</jc>
       *    WriterSerializer <jv>serializer</jv> = JsonSerializer
       *       .<jsm>create</jsm>()
       *       .ws()  <jc>// Enable whitespace</jc>
       *       .maxIndent(20)
       *       .build();
       * </p>
       *
       * @param value
       *    The new value for this property.
       *    <br>The default is <c>100</c>.
       * @return This object.
       */
      public Builder maxIndent(int value) {
         maxIndent = value;
         return this;
      }

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

      @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;
      }

      /**
       *  Quote character.
       *
       * <p>
       * Specifies the character to use for quoting attributes and values.
       *
       * <h5 class='section'>Notes:</h5><ul>
       *    <li class='note'>This setting does not apply to the RDF serializers.
       * </ul>
       *
       * <h5 class='section'>Example:</h5>
       * <p class='bjava'>
       *    <jc>// Create a serializer that uses single quotes.</jc>
       *    WriterSerializer <jv>serializer</jv> = JsonSerializer
       *       .<jsm>create</jsm>()
       *       .quoteChar(<js>'\''</js>)
       *       .build();
       *
       *    <jc>// A bean with a single property</jc>
       *    <jk>public class</jk> MyBean {
       *       <jk>public</jk> String <jf>foo</jf> = <js>"bar"</js>;
       *    }
       *
       *    <jc>// Produces {'foo':'bar'}</jc>
       *    String <jv>json</jv> = <jv>serializer</jv>.toString(<jk>new</jk> MyBean());
       * </p>
       *
       * @param value
       *    The new value for this property.
       *    <br>The default is <js>'"'</js>.
       * @return This object.
       */
      public Builder quoteChar(char value) {
         quoteChar = value;
         return this;
      }

      /**
       * Quote character override.
       *
       * <p>
       * Similar to {@link #quoteChar(char)} but takes precedence over that setting.
       *
       * <p>
       * Allows you to override the quote character even if it's set by a subclass such as {@link Json5Serializer}.
       *
       *
       * @param value
       *    The new value for this property.
       *    <br>The default is <jk>null</jk>.
       * @return This object.
       */
      public Builder quoteCharOverride(char value) {
         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;
      }

      /**
       *  Quote character.
       *
       * <p>
       * Specifies to use single quotes for quoting attributes and values.
       *
       * <h5 class='section'>Notes:</h5><ul>
       *    <li class='note'>This setting does not apply to the RDF serializers.
       * </ul>
       *
       * <h5 class='section'>Example:</h5>
       * <p class='bjava'>
       *    <jc>// Create a serializer that uses single quotes.</jc>
       *    WriterSerializer <jv>serializer</jv> = JsonSerializer
       *       .<jsm>create</jsm>()
       *       .sq()
       *       .build();
       *
       *    <jc>// A bean with a single property</jc>
       *    <jk>public class</jk> MyBean {
       *       <jk>public</jk> String <jf>foo</jf> = <js>"bar"</js>;
       *    }
       *
       *    <jc>// Produces {'foo':'bar'}</jc>
       *    String <jv>json</jv> = <jv>serializer</jv>.toString(<jk>new</jk> MyBean());
       * </p>
       *
       * @return This object.
       */
      public Builder sq() {
         return quoteChar('\'');
      }

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

      /**
       * Output stream charset.
       *
       * <p>
       * The character set to use when writing to <c>OutputStreams</c>.
       *
       * <p>
       * Used when passing in output streams and byte arrays to {@link WriterSerializer#serialize(Object, Object)}.
       *
       * <h5 class='section'>Example:</h5>
       * <p class='bjava'>
       *    <jc>// Create a serializer that writes UTF-8 files.</jc>
       *    WriterSerializer <jv>serializer</jv> = JsonSerializer
       *       .<jsm>create</jsm>()
       *       .streamCharset(Charset.<jsm>forName</jsm>(<js>"UTF-8"</js>))
       *       .build();
       *
       *    <jc>// Use it to write to a UTF-8 encoded output stream.</jc>
       *    <jv>serializer</jv>.serializer(<jk>new</jk> FileOutputStreamStream(<js>"MyBean.txt"</js>), <jv>myBean</jv>);
       * </p>
       *
       * @param value
       *    The new value for this property.
       *    <br>The default is the system JVM setting.
       *    <br>Can be <jk>null</jk> (defaults to UTF-8).
       * @return This object.
       */
      public Builder streamCharset(Charset value) {
         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;
      }

      @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;
      }

      /**
       *  Use whitespace.
       *
       * <p>
       * When enabled, whitespace is added to the output to improve readability.
       *
       * <h5 class='section'>Example:</h5>
       * <p class='bjava'>
       *    <jc>// Create a serializer with whitespace enabled.</jc>
       *    WriterSerializer <jv>serializer</jv> = JsonSerializer
       *       .<jsm>create</jsm>()
       *       .useWhitespace()
       *       .build();
       *
       *    <jc>// A bean with a single property</jc>
       *    <jk>public class</jk> MyBean {
       *       <jk>public</jk> String <jf>foo</jf> = <js>"bar"</js>;
       *    }
       *
       *    <jc>// Produces "\{\n\t"foo": "bar"\n\}\n"</jc>
       *    String <jv>json</jv> = <jv>serializer</jv>.serialize(<jk>new</jk> MyBean());
       * </p>
       *
       * @return This object.
       */
      public Builder useWhitespace() {
         return useWhitespace(true);
      }

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

      /**
       *  Use whitespace.
       *
       * <p>
       * When enabled, whitespace is added to the output to improve readability.
       *
       * <h5 class='section'>Example:</h5>
       * <p class='bjava'>
       *    <jc>// Create a serializer with whitespace enabled.</jc>
       *    WriterSerializer <jv>serializer</jv> = JsonSerializer
       *       .<jsm>create</jsm>()
       *       .ws()
       *       .build();
       *
       *    <jc>// A bean with a single property</jc>
       *    <jk>public class</jk> MyBean {
       *       <jk>public</jk> String <jf>foo</jf> = <js>"bar"</js>;
       *    }
       *
       *    <jc>// Produces "\{\n\t"foo": "bar"\n\}\n"</jc>
       *    String <jv>json</jv> = <jv>serializer</jv>.serialize(<jk>new</jk> MyBean());
       * </p>
       *
       * @return This object.
       */
      public Serializer.Builder ws() {
         return useWhitespace();
      }
   }

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

   protected final boolean useWhitespace;
   protected final Character quoteChar;
   protected final Character quoteCharOverride;
   private final Charset fileCharset;
   private final Charset streamCharset;
   protected final int maxIndent;

   private final char quoteCharValue;

   /**
    * Constructor.
    *
    * @param builder
    *    The builder for this object.
    */
   protected WriterSerializer(Builder builder) {
      super(builder);

      fileCharset = builder.fileCharset;
      maxIndent = builder.maxIndent;
      quoteChar = builder.quoteChar;
      quoteCharOverride = builder.quoteCharOverride;
      streamCharset = builder.streamCharset;
      useWhitespace = builder.useWhitespace;

      quoteCharValue = nn(quoteCharOverride) ? quoteCharOverride : nn(quoteChar) ? quoteChar : '"';
   }

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

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

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

   @Override /* Overridden from Serializer */
   public final boolean isWriterSerializer() { return true; }

   /**
    * Convenience method for serializing an object and sending it to STDOUT.
    *
    * @param o The object to serialize.
    * @return This object.
    */
   public final WriterSerializer println(Object o) {
      System.out.println(toString(o));  // NOT DEBUG
      return this;
   }

   /**
    * Convenience method for serializing an object to a <c>String</c>.
    *
    * @param o The object to serialize.
    * @return The output serialized to a string.
    * @throws SerializeException If a problem occurred trying to convert the output.
    */
   @Override /* Overridden from Serializer */
   public final String serialize(Object o) throws SerializeException {
      return getSession().serialize(o);
   }

   /**
    * Identical to {@link #serialize(Object)} except throws a {@link RuntimeException} instead of a {@link SerializeException}.
    *
    * <p>
    * This is typically good enough for debugging purposes.
    *
    * @param o The object to serialize.
    * @return The serialized object.
    */
   public final String toString(Object o) {
      try {
         return serialize(o);
      } catch (Exception e) {
         throw toRex(e);
      }
   }

   /**
    * File charset.
    *
    * @see Builder#fileCharset(Charset)
    * @return
    *    The character set to use when writing to <c>Files</c> on the file system.
    */
   protected final Charset getFileCharset() { return fileCharset; }

   /**
    * Maximum indentation.
    *
    * @see Builder#maxIndent(int)
    * @return
    *    The maximum indentation level in the serialized document.
    */
   protected final int getMaxIndent() { return maxIndent; }

   /**
    * Quote character.
    *
    * @see Builder#quoteChar(char)
    * @return
    *    The character used for quoting attributes and values.
    */
   protected char getQuoteChar() { return quoteCharValue; }

   /**
    * Output stream charset.
    *
    * @see Builder#streamCharset(Charset)
    * @return
    *    The character set to use when writing to <c>OutputStreams</c> and byte arrays.
    */
   protected final Charset getStreamCharset() { return streamCharset; }

   /**
    * Trim strings.
    *
    * @see Builder#useWhitespace()
    * @return
    *    When enabled, whitespace is added to the output to improve readability.
    */
   protected final boolean isUseWhitespace() { return useWhitespace; }

   @Override /* Overridden from Serializer */
   protected FluentMap<String,Object> properties() {
      return super.properties()
         .a("fileCharset", fileCharset)
         .a("maxIndent", maxIndent)
         .a("quoteChar", quoteChar)
         .a("streamCharset", streamCharset)
         .a("useWhitespace", useWhitespace);
   }

   /**
    * Quote character.
    *
    * @see Builder#quoteChar(char)
    * @return
    *    The character used for quoting attributes and values.
    */
   protected Character quoteChar() {
      return nn(quoteCharOverride) ? quoteCharOverride : quoteChar;
   }
}