Js实现Map对象的代码

<script type="text/javascript"><!--  
/**
 *  @author： 丸子
 *  @date:  2011-1-8 
 *  map对象类,提供了put,get,remove,size,isEmpty等方法
 */
function Map() {
 /**
  * 构造函数
  * @param {} key
  * @param {} value
  */
 var struct = function(key, value) {
  this.key = key;
  this.value = value;
 }
 /**
  * 添加key对应的值，如果key已经存在则直接更新对应的值
  * @param {} key
  * @param {} value
  */
 var put = function(key, value) {
  for (var i = 0; i < this.arr.length; i++) {
   if (this.arr[i].key === key) {
    this.arr[i].value = value;
    return;
   }
  }
  this.arr[this.arr.length] = new struct(key, value);
 }
 /**
  * 获取key对应的值
  * @param {} key
  * @return {}
  */
 var get = function(key) {
  for (var i = 0; i < this.arr.length; i++) {
   if (this.arr[i].key === key) {
    return this.arr[i].value;
   }
  }
  return null;
 }
 /**
  * 移除key对应的值
  * @param {} key
  */
 var remove = function(key) {
  var v;
  for (var i = 0; i < this.arr.length; i++) {
   v = this.arr.pop();
   if (v.key === key) {
    continue;
   }
   this.arr.unshift(v);
  }
 }
 /**
  * 获取map对象的长度
  * @return {}
  */
 var size = function() {
  return this.arr.length;
 }
 /**
  * 判断map对象是否为空
  * @return {}
  */
 var isEmpty = function() {
  return this.arr.length <= 0;
 }
 this.arr = new Array();
 this.get = get;
 this.put = put;
 this.remove = remove;
 this.size = size;
 this.isEmpty = isEmpty;
}
// -->
</script> 

<script type="text/javascript"><!--   
 var map = new Map();   
 map.put("re","redhacker");   
 map.put("do","douguoqiang");   
 map.put("gq","dougq");   
 alert("map的大小为：" + map.size())   
 alert("key为re的map中存储的对象为：" + map.get("do"));
 map.remove("re");   
 alert("移除key为re的对象后，获取key为re的map中存储的对象为：" + map.get("do"));   
 alert("map移除一个元素后的大小为：" + map.size());   
 alert("map是否是一个空map:" + map.isEmpty());   
// -->
</script>