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Java library for transforming beans, maps, collections, java arrays and XML to JSON.
There is a newer version: 2.1-rev6
/*
 * Copyright 2002-2007 the original author or authors.
 *
 * Licensed 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 net.sf.json.util;

/*
Copyright (c) 2002 JSON.org

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.

The Software shall be used for Good, not Evil.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.
*/

import java.io.StringWriter;

/**
 * JSONStringer provides a quick and convenient way of producing JSON text. The
 * texts produced strictly conform to JSON syntax rules. No whitespace is added,
 * so the results are ready for transmission or storage. Each instance of
 * JSONStringer can produce one JSON text.
 * 
 * A JSONStringer instance provides a value method for appending
 * values to the text, and a key method for adding keys before
 * values in objects. There are array and endArray
 * methods that make and bound array values, and object and
 * endObject methods which make and bound object values. All of
 * these methods return the JSONWriter instance, permitting cascade style. For
 * example,
 *
 * 
 * myString = new JSONStringer()
 *     .object()
 *         .key("JSON")
 *         .value("Hello, World!")
 *     .endObject()
 *     .toString();
 *
 * which produces the string
 *
 *  * {"JSON":"Hello, World!"}
 *
 * 
 * The first method called must be array or object.
 * There are no methods for adding commas or colons. JSONStringer adds them for
 * you. Objects and arrays can be nested up to 20 levels deep.
 * 
 * This can sometimes be easier than using a JSONObject to build a string.
 *
 * @author JSON.org
 * @version 2
 */
public class JSONStringer extends JSONBuilder {
   /**
    * Make a fresh JSONStringer. It can be used to build one JSON text.
    */
   public JSONStringer() {
      super( new StringWriter() );
   }

   /**
    * Return the JSON text. This method is used to obtain the product of the
    * JSONStringer instance. It will return null if there was a
    * problem in the construction of the JSON text (such as the calls to
    * array were not properly balanced with calls to
    * endArray).
    *
    * @return The JSON text.
    */
   public String toString() {
      return this.mode == 'd' ? this.writer.toString() : null;
   }
}