JavaScript中利用Array和Object实现Map的方法

/
  @author blune68
  @version 0.1, 07/27/12
  
 /
function Map(){
  this.keys = new Array(); 
  this.data = new Object();
  var toString = Object.prototype.toString;
  /
    当前Map当前长度
   /
  this.size = function(){
    return this.keys.length;
  }
  /
    添加值
    @param {Object} key
    @param {Object} value
   /
  this.put = function(key, value){
    if(this.data[key] == null){
      this.data[key] = value;
    }
    this.keys.push(key);
  }
  /
    根据当前key获取value
    @param {Object} key
   /
  this.get = function(key){
    return this.data[key];
  }
  /
    根据当前key移除Map对应值
    @param {Object} key
   /
  this.remove = function(key){
    var index = this.indexOf(key);
    if(index != -1){
      this.keys.splice(index, 1);
    }
    this.data[key] = null;
  }
  /
    清空Map
   /
  this.clear = function(){
    for(var i=0, len = this.size(); i < len; i++){
      var key = this.keys[i];
      this.data[key] = null;
    }
    this.keys.length = 0;
  }
  /
    当前key是否存在
    @param {Object} key
   /
  this.containsKey = function(key){
    return this.data[key] != null;
  }
  /
    是否为空
   /
  this.isEmpty = function(){
    return this.keys.length === 0;
  }
  /
    类型Java中Map.entrySet
   /
  this.entrySet = function(){
    var size = this.size();
    var datas = new Array(size);
    for (var i = 0, len = size; i < len; i++) {
      var key = this.keys[i];
      var value = this.data[key];
      datas[i] = {
        'key' : key,
        'value':value  
      }
    }
    return datas;
  }
  /
    遍历当前Map
    var map = new Map();
    map.put('key', 'value');
    map.each(function(index, key, value){
      console.log("index:" + index + "--key:" + key + "--value:" + value)
    })
    @param {Object} fn
   /
  this.each = function(fn){
    if(toString.call(fn) === '[object Function]'){
      for (var i = 0, len = this.size(); i < len; i++) {
        var key = this.keys[i];
        fn(i, key, this.data[key]);
      }
    }
    return null;
  }
  /
    获取Map中 当前key 索引值
    @param {Object} key
   /
  this.indexOf = function(key){
    var size = this.size();
    if(size > 0){
      for(var i=0, len=size; i < len; i++){
        if(this.keys[i] == key)
        return i;
      }
    }
    return -1;
  }
  /
    Override toString
   /
  this.toString = function(){
    var str = "{";
    for (var i = 0, len = this.size(); i < len; i++, str+=",") {
      var key = this.keys[i];
      var value = this.data[key];
      str += key + "=" + value; 
    }
    str = str.substring(0, str.length-1);
    str += "}";
    return str;
  }
  /
    获取Map中的所有value值(Array)
   /
  this.values = function(){
    var size = this.size();
    var values = new Array();
    for(var i = 0; i < size; i++){
      var key = this.keys[i];
      values.push(this.data[key]);
    }
    return values;
  }
}