zkoss/zk

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

import java.util.LinkedHashMap;
import java.util.Iterator;
import java.util.Map;

/**
 * A JSON object. Key value pairs are in the order of adding.
 * JSONObject supports java.util.Map interface.
 * 
 * @author FangYidong<fangyidong@yahoo.com.cn>
 */
public class JSONObject extends LinkedHashMap<Object, Object> implements Map<Object, Object>, JSONAware {
    private static final long serialVersionUID = -503443796854799292L;
    
    /**
     * Convert (aka., encode) a map to JSON text. The result is a JSON object. 
     * If this map is also a JSONAware, JSONAware specific behaviors will be omitted at this top level.
     * 
     * @see JSONValue#toJSONString(Object)
     * 
     * @param map
     * @return JSON text, or "null" if map is null.
     */
    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();
    }
    
    /** Encodes this object to a JSON string.
     * It is the same as {@link #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();
    }

    /** Encodes this object to a JSON string.
     * It is the same as {@link #toJSONString()}.
     */    
    public String toString(){
        return toJSONString();
    }

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