js map

/*
 * 时间：2014/02/22
 */
function Map()
{
    /* 定义数据结构对象*/
    var struct = function (key, value)
    {
        var toString = function ()
        {
            return this.key + ':' + this.value;
        }
        this.key = key;
        this.value = value;
        this.toString = toString;
    }
    /*
     * 创建struct对象，存放key 、value 键值对 
     * 将对象放入定义好的arr数组中
     */

    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);
    }
    /* 遍历arr数组得到key的对象，取出响应的value值*/

    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;
    }
    /* 删除arr数组中key所对应的struct对象*/

    var remove = function (key)
    {
        var v;
        for (var i = 0; i < this.arr.length; i++)
        {
            v = this.arr.pop();
            //pop：删除原数组最后一项，并返回删除元素的值；如果数组为空则返回undefined
            if (v.key === key)
            {
                continue;
            }
            this.arr.unshift(v);
            //unshift：将参数添加到原数组开头，并返回数组的长度
        }
    }
    /* 获取集合的长度 */

    var size = function ()
    {
        return this.arr.length;
    }
    /* 判读集合是否为空 */

    var isEmpty = function ()
    {
        return this.arr.length <= 0;
    }
    /* 将集合中的数据已json格式输出 */

    var toString = function ()
    {
        var string = '';
        if (this.isEmpty() == false)
        {
            for (var i = 0; i < this.arr.length; i++)
            {
                if (i == 0)
                {
                    string += this.arr[i];
                } 
                else
                {
                    string += ',' + this.arr[i];
                }
            }
        }
        return string;
    }
    /* 清空arr数组的值 */

    var clear = function ()
    {
        this.arr.length = 0
    }
    /* 得到所有的key */

    var getKeys = function ()
    {
        var keysArray = new Array();
        for (var i = 0; i < this.arr.length; i++)
        {
            keysArray.push(this.arr[i].key);
        }
        return keysArray;
    }
    this.arr = new Array();
    this.get = get;
    this.put = put;
    this.remove = remove;
    this.size = size;
    this.clear = clear;
    this.getKeys = getKeys;
    this.isEmpty = isEmpty;
    this.toString = toString;
}

var map = new Map();