[转]Js实现类似Java中的Map对象

js 代码

出处：http://redhacker.blueidea.com/archives/2006/3637.shtml
By  凌云志 发表于 2006-11-13 0:03:00


在Java中，Map对象是一个十分有用的对象，因此，我最近一直想去自己实现一个Js的Map类，后来发现网络上有一个不错的实现，参考网上流传的一个实现，我整理了一下，并且准备再加一个sort()方法，具体实现，有时间再补上。

代码如下：

<script>
 function struct(key, value) {
   this.key = key;
   this.value = value;
 }

 function put(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);
 }

 function get(key) {
   for (var i = 0; i < this.arr.length; i++) {
     if ( this.arr[i].key === key ) {
       return this.arr[i].value;
     }
   }
   return null;
 }

 function remove(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);
   }
 }

 function size() {
   return this.arr.length;
 }

 function isEmpty() {
   return this.arr.length <= 0;
 }

 function Map() {
   this.arr = new Array();
   this.get = get;
   this.put = put;
   this.remove = remove;
   this.size = size;
   this.isEmpty = isEmpty;
   this.sort = sort;
 }

 function sort() {

 }
</script>

<script>
 //测试
 var map = new Map();
 map.put("dgq","redhacker");
 map.put("dgq","douguoqiang");
 map.put(" array",["a","b","c"]);
 alert(map.get("dgq"));
 alert(map.get("array"));
</script>

===============================================

今天大致思略了一下，不能加sort()方法，原因也不罗嗦了，现在将上面的例子重新整理一下，改为一个函数，方便以后调用。

<script>
function Map() {
 var struct = function(key, value) {
  this.key = key;
  this.value = 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);
 }

 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;
 }

 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);
  }
 }

 var size = function() {
  return this.arr.length;
 }

 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>
 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("re"));
 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("re"));
 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>