gsonbuilder.java

地图生成的一个文件

  public GsonBuilder disableHtmlEscaping() {
    this.escapeHtmlChars = false;
    return this;
  }

  /**
   * Configures Gson to serialize {@code Date} objects according to the pattern provided. You can
   * call this method or {@link #setDateFormat(int)} multiple times, but only the last invocation
   * will be used to decide the serialization format.
   *
   * <p>Note that this pattern must abide by the convention provided by {@code SimpleDateFormat}
   * class. See the documentation in {@link java.text.SimpleDateFormat} for more information on
   * valid date and time patterns.</p>
   *
   * @param pattern the pattern that dates will be serialized/deserialized to/from
   * @return a reference to this {@code GsonBuilder} object to fulfill the "Builder" pattern
   * @since 1.2
   */
  public GsonBuilder setDateFormat(String pattern) {
    // TODO(Joel): Make this fail fast if it is an invalid date format
    this.datePattern = pattern;
    return this;
  }

  /**
   * Configures Gson to to serialize {@code Date} objects according to the style value provided.
   * You can call this method or {@link #setDateFormat(String)} multiple times, but only the last
   * invocation will be used to decide the serialization format.
   *
   * <p>Note that this style value should be one of the predefined constants in the
   * {@code DateFormat} class. See the documentation in {@link java.text.DateFormat} for more
   * information on the valid style constants.</p>
   *
   * @param style the predefined date style that date objects will be serialized/deserialized
   * to/from
   * @return a reference to this {@code GsonBuilder} object to fulfill the "Builder" pattern
   * @since 1.2
   */
  public GsonBuilder setDateFormat(int style) {
    this.dateStyle = style;
    this.datePattern = null;
    return this;
  }

  /**
   * Configures Gson to to serialize {@code Date} objects according to the style value provided.
   * You can call this method or {@link #setDateFormat(String)} multiple times, but only the last
   * invocation will be used to decide the serialization format.
   *
   * <p>Note that this style value should be one of the predefined constants in the
   * {@code DateFormat} class. See the documentation in {@link java.text.DateFormat} for more
   * information on the valid style constants.</p>
   *
   * @param dateStyle the predefined date style that date objects will be serialized/deserialized
   * to/from
   * @param timeStyle the predefined style for the time portion of the date objects
   * @return a reference to this {@code GsonBuilder} object to fulfill the "Builder" pattern
   * @since 1.2
   */
  public GsonBuilder setDateFormat(int dateStyle, int timeStyle) {
    this.dateStyle = dateStyle;
    this.timeStyle = timeStyle;
    this.datePattern = null;
    return this;
  }

  /**
   * Configures Gson for custom serialization or deserialization. This method combines the
   * registration of an {@link InstanceCreator}, {@link JsonSerializer}, and a
   * {@link JsonDeserializer}. It is best used when a single object {@code typeAdapter} implements
   * all the required interfaces for custom serialization with Gson. If an instance creator,
   * serializer or deserializer was previously registered for the specified {@code type}, it is
   * overwritten.
   *
   * @param type the type definition for the type adapter being registered
   * @param typeAdapter This object must implement at least one of the {@link InstanceCreator},
   * {@link JsonSerializer}, and a {@link JsonDeserializer} interfaces.
   * @return a reference to this {@code GsonBuilder} object to fulfill the "Builder" pattern
   */
  public GsonBuilder registerTypeAdapter(Type type, Object typeAdapter) {
    Preconditions.checkArgument(typeAdapter instanceof JsonSerializer
        || typeAdapter instanceof JsonDeserializer || typeAdapter instanceof InstanceCreator);
    if (typeAdapter instanceof InstanceCreator) {
      registerInstanceCreator(type, (InstanceCreator<?>) typeAdapter);
    }
    if (typeAdapter instanceof JsonSerializer) {
      registerSerializer(type, (JsonSerializer<?>) typeAdapter);
    }
    if (typeAdapter instanceof JsonDeserializer) {
      registerDeserializer(type, (JsonDeserializer<?>) typeAdapter);
    }
    return this;
  }

  /**
   * Configures Gson to use a custom {@link InstanceCreator} for the specified type. If an instance
   * creator was previously registered for the specified class, it is overwritten. Since this method
   * takes a type instead of a Class object, it can be used to register a specific handler for a
   * generic type corresponding to a raw type.
   *
   * @param <T> the type for which instance creator is being registered
   * @param typeOfT The Type definition for T
   * @param instanceCreator the instance creator for T
   * @return a reference to this {@code GsonBuilder} object to fulfill the "Builder" pattern
   */
  private <T> GsonBuilder registerInstanceCreator(Type typeOfT,
      InstanceCreator<? extends T> instanceCreator) {
    instanceCreators.register(typeOfT, instanceCreator);
    return this;
  }

  /**
   * Configures Gson to use a custom JSON serializer for the specified type. You should use this
   * method if you want to register different serializers for different generic types corresponding
   * to a raw type.
   *
   * @param <T> the type for which the serializer is being registered
   * @param typeOfT The type definition for T
   * @param serializer the custom serializer
   * @return a reference to this {@code GsonBuilder} object to fulfill the "Builder" pattern
   */
  private <T> GsonBuilder registerSerializer(Type typeOfT, final JsonSerializer<T> serializer) {
    serializers.register(typeOfT, serializer);
    return this;
  }

  /**
   * Configures Gson to use a custom JSON deserializer for the specified type. You should use this
   * method if you want to register different deserializers for different generic types
   * corresponding to a raw type.
   *
   * @param <T> the type for which the deserializer is being registered
   * @param typeOfT The type definition for T
   * @param deserializer the custom deserializer
   * @return a reference to this {@code GsonBuilder} object to fulfill the "Builder" pattern
   */
  private <T> GsonBuilder registerDeserializer(Type typeOfT, JsonDeserializer<T> deserializer) {
    deserializers.register(typeOfT, new JsonDeserializerExceptionWrapper<T>(deserializer));
    return this;
  }

  /**
   * Section 2.4 of <a href="http://www.ietf.org/rfc/rfc4627.txt">JSON specification</a> disallows
   * special double values (NaN, Infinity, -Infinity). However,
   * <a href="http://www.ecma-international.org/publications/files/ECMA-ST/Ecma-262.pdf">Javascript
   * specification</a> (see section 4.3.20, 4.3.22, 4.3.23) allows these values as valid Javascript
   * values. Moreover, most JavaScript engines will accept these special values in JSON without
   * problem. So, at a practical level, it makes sense to accept these values as valid JSON even
   * though JSON specification disallows them.
   *
   * <p>Gson always accepts these special values during deserialization. However, it outputs
   * strictly compliant JSON. Hence, if it encounters a float value {@link Float#NaN},
   * {@link Float#POSITIVE_INFINITY}, {@link Float#NEGATIVE_INFINITY}, or a double value
   * {@link Double#NaN}, {@link Double#POSITIVE_INFINITY}, {@link Double#NEGATIVE_INFINITY}, it
   * will throw an {@link IllegalArgumentException}. This method provides a way to override the
   * default behavior when you know that the JSON receiver will be able to handle these special
   * values.
   *
   * @return a reference to this {@code GsonBuilder} object to fulfill the "Builder" pattern
   * @since 1.3
   */
  public GsonBuilder serializeSpecialFloatingPointValues() {
    this.serializeSpecialFloatingPointValues = true;
    return this;
  }

  /**
   * Creates a {@link Gson} instance based on the current configuration. This method is free of
   * side-effects to this {@code GsonBuilder} instance and hence can be called multiple times.
   *
   * @return an instance of Gson configured with the options currently set in this builder
   */
  public Gson create() {
    List<ExclusionStrategy> strategies = new LinkedList<ExclusionStrategy>();
    strategies.add(modifierBasedExclusionStrategy);
    strategies.add(anonAndLocalClassExclusionStrategy);

    if (!serializeInnerClasses) {
      strategies.add(innerClassExclusionStrategy);
    }
    if (ignoreVersionsAfter != VersionConstants.IGNORE_VERSIONS) {
      strategies.add(new VersionExclusionStrategy(ignoreVersionsAfter));
    }
    if (excludeFieldsWithoutExposeAnnotation) {
      strategies.add(exposeAnnotationExclusionStrategy);
    }
    ExclusionStrategy exclusionStrategy = new DisjunctionExclusionStrategy(strategies);

    ParameterizedTypeHandlerMap<JsonSerializer<?>> customSerializers = serializers.copyOf();
    ParameterizedTypeHandlerMap<JsonDeserializer<?>> customDeserializers = deserializers.copyOf();
    addTypeAdaptersForDate(datePattern, dateStyle, timeStyle, customSerializers,
        customDeserializers);

    customSerializers.registerIfAbsent(DefaultTypeAdapters.getDefaultSerializers(
        serializeSpecialFloatingPointValues, longSerializationPolicy));

    customDeserializers.registerIfAbsent(DefaultTypeAdapters.getDefaultDeserializers());

    ParameterizedTypeHandlerMap<InstanceCreator<?>> customInstanceCreators =
        instanceCreators.copyOf();
    customInstanceCreators.registerIfAbsent(DefaultTypeAdapters.getDefaultInstanceCreators());
    
    customSerializers.makeUnmodifiable();
    customDeserializers.makeUnmodifiable();
    instanceCreators.makeUnmodifiable();
    
    MappedObjectConstructor objConstructor = new MappedObjectConstructor(customInstanceCreators);

    JsonFormatter formatter =  prettyPrinting ?
        new JsonPrintFormatter(escapeHtmlChars) : new JsonCompactFormatter(escapeHtmlChars);
    Gson gson = new Gson(exclusionStrategy, fieldNamingPolicy, objConstructor,
        formatter, serializeNulls, customSerializers, customDeserializers, generateNonExecutableJson);
    return gson;
  }

  private static void addTypeAdaptersForDate(String datePattern, int dateStyle, int timeStyle,
      ParameterizedTypeHandlerMap<JsonSerializer<?>> serializers,
      ParameterizedTypeHandlerMap<JsonDeserializer<?>> deserializers) {
    if (!serializers.hasSpecificHandlerFor(Date.class)
        && !deserializers.hasSpecificHandlerFor(Date.class)) {
      // NOTE: if a date pattern exists, then that style takes priority
      DefaultDateTypeAdapter dateTypeAdapter = null;
      if (datePattern != null && !"".equals(datePattern.trim())) {
        dateTypeAdapter = new DefaultDateTypeAdapter(datePattern);
      } else if (dateStyle != DateFormat.DEFAULT && timeStyle != DateFormat.DEFAULT) {
        dateTypeAdapter = new DefaultDateTypeAdapter(dateStyle, timeStyle);
      }
      
      if (dateTypeAdapter != null) {
        serializers.register(Date.class, dateTypeAdapter);
        deserializers.register(Date.class, dateTypeAdapter);
      }
    }
  }
}