JavaScript实现Java中的Map结构

//construction
function Map() {
 this.obj = new Object();
};
 
//add a key-value
Map.prototype.put = function(key, value) {
 this.obj[key] = value;
};
 
//get a value by a key,if don't exist,return undefined
Map.prototype.get = function(key) {
 return this.obj[key];
};
 
//remove a value by a key
Map.prototype.remove = function(key) {
 if(this.get(key)==undefined) {
 return;
 }
 delete this.obj[key];
};
 
//clear the map
Map.prototype.clear = function() {
 this.obj = new Object();
};
 
//get the size
Map.prototype.size = function() {
 var ary = this.keys();
 return ary.length;
};
 
//get all keys
Map.prototype.keys = function() {
 var ary = new Array();
 for(var temp in this.obj) {
 ary.push(temp);
 }
 return ary;
};
 
//get all values
Map.prototype.values = function() {
 var ary = new Array();
 for(var temp in this.obj) {
 ary.push(this.obj[temp]);
 }
 return ary;
};