content: /*
   * This library is part of OpenCms -
   * the Open Source Content Management System
   *
   * Copyright (c) Alkacon Software GmbH & Co. KG (https://www.alkacon.com)
   *
   * This library is free software; you can redistribute it and/or
   * modify it under the terms of the GNU Lesser General Public
   * License as published by the Free Software Foundation; either
   * version 2.1 of the License, or (at your option) any later version.
   *
   * This library is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
   * Lesser General Public License for more details.
   *
   * For further information about Alkacon Software GmbH & Co. KG, please see the
   * company website: https://www.alkacon.com
   *
   * For further information about OpenCms, please see the
   * project website: https://www.opencms.org
   *
   * You should have received a copy of the GNU Lesser General Public
   * License along with this library; if not, write to the Free Software
   * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
   *
   * This file is based on:
   * org.json.JSONWriter
   * from the JSON in Java implementation.
   *
   * 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.
   */
  
  package org.opencms.json;
  
  import java.io.IOException;
  import java.io.Writer;
  
  /**
   * JSONWriter 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
   * JSONWriter can produce one JSON text.
   * <p>
   * A JSONWriter instance provides a <code>value</code> method for appending
   * values to the
   * text, and a <code>key</code>
   * method for adding keys before values in objects. There are <code>array</code>
   * and <code>endArray</code> methods that make and bound array values, and
   * <code>object</code> and <code>endObject</code> methods which make and bound
   * object values. All of these methods return the JSONWriter instance,
   * permitting a cascade style. For example, <pre>
   * new JSONWriter(myWriter)
   *     .object()
   *         .key("JSON")
   *         .value("Hello, World!")
   *     .endObject();</pre> which writes <pre>
   * {"JSON":"Hello, World!"}</pre>
   * <p>
   * The first method called must be <code>array</code> or <code>object</code>.
   * There are no methods for adding commas or colons. JSONWriter adds them for
   * you. Objects and arrays can be nested up to 20 levels deep.
   * <p>
   * This can sometimes be easier than using a JSONObject to build a string.<p>
   *
   */
  public class JSONWriter {
  
      /** The maximum depth. */
      private static final int MAXDEPTH = 20;
  
      /**
       * The current m_mode. Values:
       * 'a' (array),
       * 'd' (done),
       * 'i' (initial),
       * 'k' (key),
       * 'o' (object).
       */
      protected char m_mode;
  
      /**
       * The m_writer that will receive the output.
       */
      protected Writer m_writer;
  
      /**
       * The m_comma flag determines if a m_comma should be output before the next
       * value.
       */
      private boolean m_comma;
  
      /**
       * The object/array m_stack.
       */
      private char[] m_stack;
  
      /**
       * The m_stack m_top index. A value of 0 indicates that the m_stack is empty.
       */
      private int m_top;
  
      /**
       * Make a fresh JSONWriter.<p>
       *
       * It can be used to build one JSON text.<p>
       *
       * @param w the writer to use
       */
      public JSONWriter(Writer w) {
  
          m_comma = false;
          m_mode = 'i';
          m_stack = new char[MAXDEPTH];
          m_top = 0;
          m_writer = w;
      }
  
      /**
       * Begin appending a new array.<p>
       *
       * All values until the balancing
       * <code>endArray</code> will be appended to this array. The
       * <code>endArray</code> method must be called to mark the array's end.<p>
       *
       * @return this
       * @throws JSONException if the nesting is too deep, or if the object is
       * started in the wrong place (for example as a key or after the end of the
       * outermost array or object)
       */
      public JSONWriter array() throws JSONException {
  
          if ((m_mode == 'i') || (m_mode == 'o') || (m_mode == 'a')) {
              push('a');
              append("[");
              m_comma = false;
              return this;
          }
          throw new JSONException("Misplaced array.");
      }
  
      /**
       * End an array. This method most be called to balance calls to
       * <code>array</code>.<p>
       *
       * @return this
       * @throws JSONException if incorrectly nested
       */
      public JSONWriter endArray() throws JSONException {
  
          return end('a', ']');
      }
  
      /**
       * End an object. This method most be called to balance calls to
       * <code>object</code>.<p>
       *
       * @return this
       * @throws JSONException if incorrectly nested
       */
      public JSONWriter endObject() throws JSONException {
  
          return end('k', '}');
      }
  
      /**
       * Append a key. The key will be associated with the next value. In an
       * object, every value must be preceded by a key.<p>
       *
       * @param s a key string
       * @return this
       * @throws JSONException if the key is out of place. For example, keys
       *  do not belong in arrays or if the key is null
       */
      public JSONWriter key(String s) throws JSONException {
  
          if (s == null) {
              throw new JSONException("Null key.");
          }
          if (m_mode == 'k') {
              try {
                  if (m_comma) {
                      m_writer.write(',');
                  }
                  m_writer.write(JSONObject.quote(s));
                  m_writer.write(':');
                  m_comma = false;
                  m_mode = 'o';
                  return this;
              } catch (IOException e) {
                  throw new JSONException(e);
              }
          }
          throw new JSONException("Misplaced key.");
      }
  
      /**
       * Begin appending a new object.<p>
       *
       * All keys and values until the balancing
       * <code>endObject</code> will be appended to this object. The
       * <code>endObject</code> method must be called to mark the object's end.<p>
       *
       * @return this
       * @throws JSONException if the nesting is too deep, or if the object is
       * started in the wrong place (for example as a key or after the end of the
       * outermost array or object)
       */
      public JSONWriter object() throws JSONException {
  
          if (m_mode == 'i') {
              m_mode = 'o';
          }
          if ((m_mode == 'o') || (m_mode == 'a')) {
              append("{");
              push('k');
              m_comma = false;
              return this;
          }
          throw new JSONException("Misplaced object.");
  
      }
  
      /**
       * Append either the value <code>true</code> or the value
       * <code>false</code>.<p>
       *
       * @param b a boolean
       * @return this
       * @throws JSONException if something goes wrong
       */
      public JSONWriter value(boolean b) throws JSONException {
  
          return append(b ? "true" : "false");
      }
  
      /**
       * Append a double value.<p>
       *
       * @param d a double
       * @return this
       * @throws JSONException if the number is not finite
       */
      public JSONWriter value(double d) throws JSONException {
  
          return this.value(Double.valueOf(d));
      }
  
      /**
       * Append a long value.<p>
       *
       * @param l a long
       * @return this
       * @throws JSONException if something goes wrong
       */
      public JSONWriter value(long l) throws JSONException {
  
          return append(Long.toString(l));
      }
  
      /**
       * Append an object value.<p>
       *
       * @param o the object to append. It can be null, or a Boolean, Number,
       *   String, JSONObject, or JSONArray, or an object with a toJSONString()
       *   method
       * @return this
       * @throws JSONException if the value is out of sequence
       */
      public JSONWriter value(Object o) throws JSONException {
  
          return append(JSONObject.valueToString(o));
      }
  
      /**
       * Append a value.<p>
       *
       * @param s a string value
       * @return this
       * @throws JSONException if the value is out of sequence
       */
      private JSONWriter append(String s) throws JSONException {
  
          if (s == null) {
              throw new JSONException("Null pointer");
          }
          if ((m_mode == 'o') || (m_mode == 'a')) {
              try {
                  if (m_comma && (m_mode == 'a')) {
                      m_writer.write(',');
                  }
                  m_writer.write(s);
              } catch (IOException e) {
                  throw new JSONException(e);
              }
              if (m_mode == 'o') {
                  m_mode = 'k';
              }
              m_comma = true;
              return this;
          }
          throw new JSONException("Value out of sequence.");
      }
  
      /**
       * End something.<p>
       *
       * @param m mode
       * @param c closing character
       * @return this
       * @throws JSONException if unbalanced
       */
      private JSONWriter end(char m, char c) throws JSONException {
  
          if (m_mode != m) {
              throw new JSONException(m == 'o' ? "Misplaced endObject." : "Misplaced endArray.");
          }
          pop(m);
          try {
              m_writer.write(c);
          } catch (IOException e) {
              throw new JSONException(e);
          }
          m_comma = true;
          return this;
      }
  
      /**
       * Pop an array or object scope.<p>
       *
       * @param c the scope to close
       * @throws JSONException zf nesting is wrong
       */
      private void pop(char c) throws JSONException {
  
          if ((m_top <= 0) || (m_stack[m_top - 1] != c)) {
              throw new JSONException("Nesting error.");
          }
          m_top -= 1;
          m_mode = m_top == 0 ? 'd' : m_stack[m_top - 1];
      }
  
      /**
       * Push an array or object scope.<p>
       *
       * @param c the scope to open
       * @throws JSONException if nesting is too deep
       */
      private void push(char c) throws JSONException {
  
          if (m_top >= MAXDEPTH) {
              throw new JSONException("Nesting too deep.");
          }
          m_stack[m_top] = c;
          m_mode = c;
          m_top += 1;
      }
  }
  