* java版HashMap，大数据量时效率很低，建议1000条数据以下使用

 

/*
 * java版HashMap，大数据量时效率很低，建议1000条数据以下使用
 */
function HashMap(){
   
    var DEFAULT_CAPACITY=16;
    var MAX_CAPACITY=2147483647;
    var DEFAULT_LOAD_FACTOR=0.75;
    /************ splitline ***************/
    var loadFactor=DEFAULT_CAPACITY;
    var threshold=DEFAULT_CAPACITY*DEFAULT_LOAD_FACTOR*1;
    //entry table
    var entryTable=new Array(DEFAULT_CAPACITY);
    var size=0;
   
    /**
     * return null if no key exists, else return the newValue replaced..
     */
    this.put=function(key,val){      
        if(key!=null){
            var hash=newHash(hashCode(key));
            var i=indexFor(hash,entryTable.length);
            for(var obj=entryTable[i];obj!=null;obj=obj.next){
                if(obj.hash==hash &&obj.key==key ){
                    var oldVal=obj.val;
                    obj.val=val;
                    return oldVal;
                }
            }
            addEntry(hash,key,val,i);
            return null;
        }
    };

    /**
     * remove the key element
     */
    this.remove=function(key){

        if(key!=null){
            var hash=newHash(hashCode(key));
            var i=indexFor(hash,entryTable.length);
            var prev = entryTable[i];
            var e = prev;
            while (e != null) {
                var next = e.next;
                if (e.hash == hash && key==e.key) {
                    size--;
                    if (prev == e)
                        entryTable[i] = next;
                    else
                        prev.next = next;
                    if(e!=null)
                        return e.val;
                }
                prev = e;
                e = next;
            }
        }
    };

    this.get=function(key){
        if(key!=null){
            var hash=newHash(hashCode(key));
            var i=indexFor(hash,entryTable.length);
            for(var obj=entryTable[i];obj!=null;obj=obj.next){
                if(obj.hash==hash && obj.key==key ){
                    return obj.val;
                }
            }
        }
    };
    this.containsKey=function(key){
        if(key!=null){
            var hash=newHash(hashCode(key));
            var i=indexFor(hash,entryTable.length);
            for(var obj=entryTable[i];obj!=null;obj=obj.next){
                if(obj.key==key  && obj.hash==hash ){
                    return true;
                }
            }
        }
        return false;
    };

    this.containsValue=function(value){
        if(value!=null){
            var tab = entryTable;
            for (var i = 0; i < tab.length ; i++)
                for (var e = tab[i] ; e != null ; e = e.next)
                    if (value.equals(e.val))
                        return true;
        }
        return false;
    }

    this.size=function(){
        return size;
    };
   
    this.getkeylist=function(){
        var tmpKey=new Array();
        for(var i=0;i<entryTable.length;i++){
            for(var obj=entryTable[i];obj!=null;obj=obj.next){
                tmpKey.push(obj.key);
            }
        }
        return tmpKey;
    };
   
    this.clear=function(){
        //modCount++;
        var t=entryTable;
        for(var i=0;i<entryTable.length;i++)
            t[i]=null;
        size=0;
    }

    function addEntry(h,k,v,index){
        var entry=entryTable[index];
        var item={"hash":h,"key":k,"val":v,"next":entry};
        entryTable[index]=item;
        if(size++>=threshold){
            resize(2*entryTable.length);
        }
    //alert(index+","+entryTable[index].next.hash);
    };
   
    function resize(newCapacity){
        var newTable=new Array(newCapacity);
        transfer(newTable);
        entryTable=newTable;
        threshold=newCapacity*loadFactor*1;
    };

   
    function transfer(newTable) {
        var src = entryTable;
        var newCapacity = newTable.length;
        for (var j = 0,len=src.length; j <len; j++) {
            var e = src[j];
            if (e != null) {
                src[j] = null;
                do {
                    var next = e.next;
                    var i = indexFor(e.hash, newCapacity); 
                    e.next = newTable[i];
                    newTable[i] = e;
                    e = next;
                } while (e != null);
            }
        }
    };

    function indexFor(h,len){
        return h&(len-1);
    };

    function newHash(h){
        h += ~(h << 9);
        h ^=  (h >>> 14);
        h +=  (h << 4);
        h ^=  (h >>> 10);
        return h;
    };

    function hashCode(str){
        var h = 0, off = 0;
        var len = str.length;

        for(var i = 0; i < len; i++){
            var tmp=str.charCodeAt(off++);
            h = 31 * h  + tmp;
            if(h>0x7fffffff || h<0x80000000){
                h=h & 0xffffffff;
            }
        }
        return h;
    };
}