導讀：
* 模擬簡單HashMap類，要求key是String，value可以是任何類型
* 方法列表：
* 1，HashMap() : 構造函數
* 2, put(key, value) : void
* 3, get(key) : Object
* 4, keySet() : Array
* 5, values() : Array
* 6, size() : int
* 7, clear() : void
* 8, isEmpty() : boolean
* 9, containsKey(key) : boolean
* 10, containsValue(value) : boolean //如果value是Object類型或者數組類型，存在bug
* 11, putAll(map) : void
* 12, remove(key) : void
* 用法：
* var map = new JHashMap();
* map.put("one","一隻小豬");
* map.put("two","兩隻小豬");
* map.put("three","三隻小豬");
*
* print("[ toString() ] : "+ map);
* print("[ get() ] : "+ map.get("one"));
* print("[ keySet() ] : "+ map.keySet());
* print("[ values() ] : "+ map.values());
* print("[ size() ] : "+ map.size());
* print("[ isEmpty() ] : "+ map.isEmpty());
* print("[ containsKey() ] : "+ map.containsKey("one"));
* print("[ containsValue() ] : "+ map.containsValue("三隻小豬"));
*
* //putAll
* var mapTemp = new JHashMap();
* mapTemp.put("four","四隻小豬");
* mapTemp.put("five","五隻小豬");
* map.putAll(mapTemp);
* print("[ putAll() ] : "+ map);
*
* //remove
* map.remove("two");
* map.remove("one");
* print("[ remove() ] : "+ map);
*
* //clear
* map.clear()
* print("[ clear() ] : "+ map.size());
* //輔助方法
* function print(msg)
* {
* document.write(msg + "");
* }
* 修改履歷：
-------------------------------------------------------------------------------*/
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/**
* HashMap構造函數
*/
function JHashMap()
{
this.length = 0;
this.prefix = "hashmap_prefix_20040716_";
}
/**
* 向HashMap中添加鍵值對
*/
JHashMap.prototype.put = function (key, value)
{
this[this.prefix + key] = value;
this.length ++;
}
/**
* 從HashMap中獲取value值
*/
JHashMap.prototype.get = function(key)
{
return typeof this[this.prefix + key] == "undefined"
null : this[this.prefix + key];
}
/**
* 從HashMap中獲取所有key的集合，以數組形式返回
*/
JHashMap.prototype.keySet = function()
{
var arrKeySet = new Array();
var index = 0;
for(var strKey in this)
{
if(strKey.substring(0,this.prefix.length) == this.prefix)
arrKeySet[index ++] = strKey.substring(this.prefix.length);
}
return arrKeySet.length == 0 ? null : arrKeySet;
}
/**
* 從HashMap中獲取value的集合，以數組形式返回
*/
JHashMap.prototype.values = function()
{
var arrValues = new Array();
var index = 0;
for(var strKey in this)
{
if(strKey.substring(0,this.prefix.length) == this.prefix)
arrValues[index ++] = this[strKey];
}
return arrValues.length == 0 ? null : arrValues;
}
/**
* 獲取HashMap的value值數量
*/
JHashMap.prototype.size = function()
{
return this.length;
}
/**
* 刪除指定的值
*/
JHashMap.prototype.remove = function(key)
{
delete this[this.prefix + key];
this.length --;
}
/**
* 清空HashMap
*/
JHashMap.prototype.clear = function()
{
for(var strKey in this)
{
if(strKey.substring(0,this.prefix.length) == this.prefix)
delete this[strKey];
}
this.length = 0;
}
/**
* 判斷HashMap是否爲空
*/
JHashMap.prototype.isEmpty = function()
{
return this.length == 0;
}
/**
* 判斷HashMap是否存在某個key
*/
JHashMap.prototype.containsKey = function(key)
{
for(var strKey in this)
{
if(strKey == this.prefix + key)
return true;
}
return false;
}
/**
* 判斷HashMap是否存在某個value
*/
JHashMap.prototype.containsValue = function(value)
{
for(var strKey in this)
{
if(this[strKey] == value)
return true;
}
return false;
}
/**
* 把一個HashMap的值加入到另一個HashMap中，參數必須是HashMap
*/
JHashMap.prototype.putAll = function(map)
{
if(map == null)
return;
if(map.constructor != JHashMap)
return;
var arrKey = map.keySet();
var arrValue = map.values();
for(var i in arrKey)
this.put(arrKey[i],arrValue[i]);
}
//toString
JHashMap.prototype.toString = function()
{
var str = "";
for(var strKey in this)
{
if(strKey.substring(0,this.prefix.length) == this.prefix)
str += strKey.substring(this.prefix.length)
+ ": "+ this[strKey] + "/r/n";
}
return str;
}
你相當於是用對象的屬性可增可減來模擬HashMap的key和value的集合的。
但你有一點點忽視的問題。當
頁面定義了Object.prototype時，你在for( var p in this )時會將Object.prototype也納入其中。
如果是我設計，我會做成：
function HashMap()
{
this.key = [];
this.value = [];
}做成2個集合的形式。
本文轉自
http://www.busfly.cn/CSDN/post/535.html