001package org.json;
002
003/*
004Copyright (c) 2006 JSON.org
005
006Permission is hereby granted, free of charge, to any person obtaining a copy
007of this software and associated documentation files (the "Software"), to deal
008in the Software without restriction, including without limitation the rights
009to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
010copies of the Software, and to permit persons to whom the Software is
011furnished to do so, subject to the following conditions:
012
013The above copyright notice and this permission notice shall be included in all
014copies or substantial portions of the Software.
015
016The Software shall be used for Good, not Evil.
017
018THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
019IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
020FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
021AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
022LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
023OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
024SOFTWARE.
025*/
026
027import java.io.StringWriter;
028
029/**
030 * JSONStringer provides a quick and convenient way of producing JSON text.
031 * The texts produced strictly conform to JSON syntax rules. No whitespace is
032 * added, so the results are ready for transmission or storage. Each instance of
033 * JSONStringer can produce one JSON text.
034 * <p>
035 * A JSONStringer instance provides a <code>value</code> method for appending
036 * values to the
037 * text, and a <code>key</code>
038 * method for adding keys before values in objects. There are <code>array</code>
039 * and <code>endArray</code> methods that make and bound array values, and
040 * <code>object</code> and <code>endObject</code> methods which make and bound
041 * object values. All of these methods return the JSONWriter instance,
042 * permitting cascade style. For example, <pre>
043 * myString = new JSONStringer()
044 *     .object()
045 *         .key("JSON")
046 *         .value("Hello, World!")
047 *     .endObject()
048 *     .toString();</pre> which produces the string <pre>
049 * {"JSON":"Hello, World!"}</pre>
050 * <p>
051 * The first method called must be <code>array</code> or <code>object</code>.
052 * There are no methods for adding commas or colons. JSONStringer adds them for
053 * you. Objects and arrays can be nested up to 20 levels deep.
054 * <p>
055 * This can sometimes be easier than using a JSONObject to build a string.
056 * @author JSON.org
057 * @version 2015-12-09
058 */
059public class JSONStringer extends JSONWriter {
060    /**
061     * Make a fresh JSONStringer. It can be used to build one JSON text.
062     */
063    public JSONStringer() {
064        super(new StringWriter());
065    }
066
067    /**
068     * Return the JSON text. This method is used to obtain the product of the
069     * JSONStringer instance. It will return <code>null</code> if there was a
070     * problem in the construction of the JSON text (such as the calls to
071     * <code>array</code> were not properly balanced with calls to
072     * <code>endArray</code>).
073     * @return The JSON text.
074     */
075    public String toString() {
076        return this.mode == 'd' ? this.writer.toString() : null;
077    }
078}