JavaScript Hashtable 修正版源码与功能详解

修正版 Hashtable 核心功能介绍

此版本修正了 Hashtable 对象中 set 方法的一个特定 Bug，该 Bug 会导致调用 obj.set("length", "0") 时出现异常或错误行为。

新增功能支持在 Hashtable 中设置键名忽略大小写，使得查找和存储键值对时不区分大小写。

实现了 Hashtable 对象的克隆功能，允许用户复制整个哈希表实例。

增加了 valueOf 方法的支持，允许通过 obj.valueOf("key", "defaultvalue") 的形式在键不存在时返回指定的默认值。

欢迎开发者继续测试并修正其中可能存在的其他 Bug。

 
<html>
<head>
<script type="text/javascript">
// Authors Birdshome, 麻袋@博客园 改版 phito,彭海涛
Object.prototype.Clone = function()
{ 
var objClone;
if ( this.constructor == Object ) objClone = new this.constructor();
else objClone = new this.constructor(this.valueOf());
for ( var key in this )
{ 
if ( objClone[key] != this[key] )
{ 
if ( typeof(this[key]) == 'object' )
{ 
objClone[key] = this[key].Clone();
} 
else
{ 
objClone[key] = this[key];
} 
} 
} 
objClone.toString = this.toString;
objClone.valueOf = this.valueOf;
return objClone;
} 
function Hashtable() {
this.clear = hashtable_clear;
this.containsKey = hashtable_containsKey;
this.containsValue = hashtable_containsValue;
this.get = hashtable_get;
this.isEmpty = hashtable_isEmpty;
this.keys = hashtable_keys;
this.put = hashtable_put;
this.remove = hashtable_remove;
this.size = hashtable_size;
this.toString = hashtable_toString;
this.values = hashtable_values;
this.hashtable = new Object();
this.set = hashtable_set;
this.valueOf = hashtable_valueOf;
this.clone = hashtable_clone;
this.ignoreupperlower = true;
//是否忽略大小写
} 
/*=======Private methods for internal use only========*/
function hashtable_clone(){
return this.Clone();
} 
function hashtable_put(key, value) {
if (this.ignoreupperlower && typeof(key) == "string") {
key = key.toUpperCase();
} 
if (key == null || value == null) {
throw "NullPointerException {" + key + "," + value + "}";
} else {
this.hashtable[key] = value;
} 
} 
function hashtable_set(key, value) {
if (this.ignoreupperlower && typeof(key) == "string") {
key = key.toUpperCase();
} 
if (this.containsKey(key)) {
this.remove(key);
} 
this.put(key, value);
} 
function hashtable_get(key) {
if (this.ignoreupperlower && typeof(key) == "string") {
key = key.toUpperCase();
} 
return this.hashtable[key];
} 
function hashtable_valueOf(key, defvalue) {
var ret = this.get(key);
if (typeof(ret) == "undefined") {
return defvalue;
} 
return ret;
} 
function hashtable_remove(key) {
if (this.containsKey(key)) {
delete this.hashtable[key] ;
} 
} 
function hashtable_isEmpty() {
return (parseInt(this.size()) == 0) ? true: false;
} 
function hashtable_size() {
var size = 0;
for (var i in this.hashtable) {
if(typeof(this.hashtable[i])=="function"){
continue;
} 
if (this.hashtable[i] != null) {
size++;
} 
} 
return size;
} 
function hashtable_toString() {
var result = "";
for (var i in this.hashtable) {
if(typeof(this.hashtable[i])=="function"){
continue;
} 
if (this.hashtable[i] != null) {
result += "{" + i + ":" + this.hashtable[i] + "}\n";
} 
} 
return result;
} 
function hashtable_clear() {
this.hashtable = new Object();
} 
function hashtable_containsKey(key) {
if (this.ignoreupperlower && typeof(key) == "string") {
key = key.toUpperCase();
} 
var exists = false;
for (var i in this.hashtable) {
if(typeof(this.hashtable[i])=="function"){
continue;
} 
if (i == key && this.hashtable[i] != null) {
exists = true;
break;
} 
} 
return exists;
} 
function hashtable_containsValue(value) {
var contains = false;
if (value != null) {
for (var i in this.hashtable) {
if(typeof(this.hashtable[i])=="function"){
continue;
} 
if (this.hashtable[i] == value) {
contains = true;
break;
} 
} 
} 
return contains;
} 
function hashtable_values() {
var values = new Object();
for (var i in this.hashtable) {
if(typeof(this.hashtable[i])=="function"){
continue;
} 
if (this.hashtable[i] != null) values.push(this.hashtable[i]);
} 
return values;
} 
function hashtable_keys() {
var keys = new Object();
for (var i in this.hashtable) {
if(typeof(this.hashtable[i])=="function"){
continue;
} 
keys.push(i);
} 
return keys;
} 
function test() {
var ht = new Hashtable();
ht.put("3", "Jackson");
ht.put("2", "Tom");
ht.put("4", 3);
ht.set("length", 445555);
ht.set("ddd", "ddd");
ht.set("index", "ddd");
var et = ht.toString();
ht.ignoreupperlower = false;
//忽略大小写
ht.clear();
ht.put("3", "Jackson");
ht.put("2", "Tom");
ht.remove("2");
ht.put("4", 3);
ht.set("length", 5);
//如果用new Array的话该项会设置Array的长度
ht.set("index", "ddd");
ht.set("ddd", "ddd");
alert(et + "" + ht.toString() + "" + ht.size());
var cloneobj=ht.clone();
alert(cloneobj.toString());
} 
</script>
</head>
<body onload="test()">
</body>
</html>

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