001/* 002 * This library is part of OpenCms - 003 * the Open Source Content Management System 004 * 005 * Copyright (c) Alkacon Software GmbH & Co. KG (http://www.alkacon.com) 006 * 007 * This library is free software; you can redistribute it and/or 008 * modify it under the terms of the GNU Lesser General Public 009 * License as published by the Free Software Foundation; either 010 * version 2.1 of the License, or (at your option) any later version. 011 * 012 * This library is distributed in the hope that it will be useful, 013 * but WITHOUT ANY WARRANTY; without even the implied warranty of 014 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 015 * Lesser General Public License for more details. 016 * 017 * For further information about Alkacon Software GmbH & Co. KG, please see the 018 * company website: http://www.alkacon.com 019 * 020 * For further information about OpenCms, please see the 021 * project website: http://www.opencms.org 022 * 023 * You should have received a copy of the GNU Lesser General Public 024 * License along with this library; if not, write to the Free Software 025 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA 026 * 027 * This file is based on: 028 * org.json.JSONStringer 029 * from the JSON in Java implementation. 030 * 031 * Copyright (c) 2002 JSON.org 032 * 033 * Permission is hereby granted, free of charge, to any person obtaining a copy 034 * of this software and associated documentation files (the "Software"), to deal 035 * in the Software without restriction, including without limitation the rights 036 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell 037 * copies of the Software, and to permit persons to whom the Software is 038 * furnished to do so, subject to the following conditions: 039 * 040 * The above copyright notice and this permission notice shall be included in all 041 * copies or substantial portions of the Software. 042 * 043 * The Software shall be used for Good, not Evil. 044 * 045 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 046 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 047 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE 048 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 049 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, 050 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE 051 * SOFTWARE. 052 */ 053 054package org.opencms.json; 055 056import java.io.StringWriter; 057 058/** 059 * JSONStringer provides a quick and convenient way of producing JSON text. 060 * The texts produced strictly conform to JSON syntax rules. No whitespace is 061 * added, so the results are ready for transmission or storage. Each instance of 062 * JSONStringer can produce one JSON text. 063 * <p> 064 * A JSONStringer instance provides a <code>value</code> method for appending 065 * values to the 066 * text, and a <code>key</code> 067 * method for adding keys before values in objects. There are <code>array</code> 068 * and <code>endArray</code> methods that make and bound array values, and 069 * <code>object</code> and <code>endObject</code> methods which make and bound 070 * object values. All of these methods return the JSONWriter instance, 071 * permitting cascade style. For example, <pre> 072 * myString = new JSONStringer() 073 * .object() 074 * .key("JSON") 075 * .value("Hello, World!") 076 * .endObject() 077 * .toString();</pre> which produces the string <pre> 078 * {"JSON":"Hello, World!"}</pre> 079 * <p> 080 * The first method called must be <code>array</code> or <code>object</code>. 081 * There are no methods for adding commas or colons. JSONStringer adds them for 082 * you. Objects and arrays can be nested up to 20 levels deep. 083 * <p> 084 * This can sometimes be easier than using a JSONObject to build a string. 085 */ 086public class JSONStringer extends JSONWriter { 087 088 /** 089 * Make a fresh JSONStringer. It can be used to build one JSON text. 090 */ 091 public JSONStringer() { 092 093 super(new StringWriter()); 094 } 095 096 /** 097 * Return the JSON text. This method is used to obtain the product of the 098 * JSONStringer instance. It will return <code>null</code> if there was a 099 * problem in the construction of the JSON text (such as the calls to 100 * <code>array</code> were not properly balanced with calls to 101 * <code>endArray</code>). 102 * @return The JSON text. 103 */ 104 @Override 105 public String toString() { 106 107 return m_mode == 'd' ? m_writer.toString() : null; 108 } 109}