JSONObject.java

/*
 * $Id: JSONObject.java,v 1.1 2006/04/15 14:10:48 platform Exp $
 * Created on 2006-4-10
 */
package org.json.simple;

import java.io.IOException;
import java.io.Writer;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;

/**
 * A JSON object. Key value pairs are unordered. JSONObject supports java.util.Map interface.
 *
 * @author FangYidong<fangyidong@yahoo.com.cn>
 */
public class JSONObject extends HashMap implements Map, JSONAware, JSONStreamAware {
  private static final long serialVersionUID = -503443796854799292L;

  /**
   * Encode a map into JSON text and write it to out.
   * If this map is also a JSONAware or JSONStreamAware, JSONAware or JSONStreamAware specific behaviours will be ignored at this top level.
   *
   * @param map
   * @param out
   * @see org.json.simple.JSONValue#writeJSONString(Object, Writer)
   */
  public static void writeJSONString(Map map, Writer out) throws IOException {
    if (map == null) {
      out.write("null");
      return;
    }

    boolean first = true;
    Iterator iter = map.entrySet().iterator();

    out.write('{');
    while (iter.hasNext()) {
      if (first)
        first = false;
      else
        out.write(',');
      Map.Entry entry = (Map.Entry) iter.next();
      out.write('\"');
      out.write(escape(String.valueOf(entry.getKey())));
      out.write('\"');
      out.write(':');
      JSONValue.writeJSONString(entry.getValue(), out);
    }
    out.write('}');
  }

  public void writeJSONString(Writer out) throws IOException {
    writeJSONString(this, out);
  }

  /**
   * Convert a map to JSON text. The result is a JSON object.
   * If this map is also a JSONAware, JSONAware specific behaviours will be omitted at this top level.
   *
   * @param map
   * @return JSON text, or "null" if map is null.
   * @see org.json.simple.JSONValue#toJSONString(Object)
   */
  public static String toJSONString(Map map) {
    if (map == null)
      return "null";

    StringBuffer sb = new StringBuffer();
    boolean first = true;
    Iterator iter = map.entrySet().iterator();

    sb.append('{');
    while (iter.hasNext()) {
      if (first)
        first = false;
      else
        sb.append(',');

      Map.Entry entry = (Map.Entry) iter.next();
      toJSONString(String.valueOf(entry.getKey()), entry.getValue(), sb);
    }
    sb.append('}');
    return sb.toString();
  }

  public String toJSONString() {
    return toJSONString(this);
  }

  private static String toJSONString(String key, Object value, StringBuffer sb) {
    sb.append('\"');
    if (key == null)
      sb.append("null");
    else
      JSONValue.escape(key, sb);
    sb.append('\"').append(':');

    sb.append(JSONValue.toJSONString(value));

    return sb.toString();
  }

  public String toString() {
    return toJSONString();
  }

  public static String toString(String key, Object value) {
    StringBuffer sb = new StringBuffer();
    toJSONString(key, value, sb);
    return sb.toString();
  }

  /**
   * Escape quotes, \, /, \r, \n, \b, \f, \t and other control characters (U+0000 through U+001F).
   * It's the same as JSONValue.escape() only for compatibility here.
   *
   * @param s
   * @return
   * @see org.json.simple.JSONValue#escape(String)
   */
  public static String escape(String s) {
    return JSONValue.escape(s);
	}
}