Multiple XMLHttpRequest objects on one page_javascript skills

I just posted a post on ajacn about providing an object pool for XMLHttpRequest. Maybe it can help you, repost it as follows:

I saw some comrades on the Internet mentioned providing an object pool for Ajax's XMLHttpRequest, and also read the implementation code they gave. It didn't feel particularly ideal, so I wrote a simple JavaScript version imitating the idea of ​​ObjectPool in apache's commons.
Hope for advice:


Code
function ObjectPool(poolableObjectFactory) {                                                                                This._activePool = []; 
} 
//Lease an object from the object pool. If there is no free object currently available, create one through poolableObjectFactory 
//Since it is borrowed, remember to return it after use. !    
ObjectPool.prototype.borrowObject = function() {    
    var object = null;    
    var idlePool = this._idlePool;    
    var factory = this._poolableObjectFactory;    
    if (idlePool.length > 0) {    
        object = idlePool.pop();    
    }    
    else {    
        object = factory.makeObject();    
    }    
    if (object != null) {    
        this._activePool.push(object);    
        if (factory.activateObject) {    
            factory.activateObject(object);    
        }    
    }    
    return object;    
}    
// 归还一个对象    
ObjectPool.prototype.returnObject = function(object) {    
    function indexOf(array, object) {    
        for (var i = 0; i             if (array[i] == object) return i;    
        }    
        return -1;    
    }    
    if (object != null) {    
        var activePool = this._activePool;    
        var factory = this._poolableObjectFactory;          
        var i = indexOf(activePool, object);    
        if (i         if (factory.passivateObject) {    
            factory.passivateObject(object);    
        }           
        activePool.splice(i, 1);    
        this._idlePool.push(object);    
    }    
}    
// 返回当前激活对象的个数    
ObjectPool.prototype.getNumActive = function() {    
    return this._activePool.length;    
}    
// 返回当前空闲对象的个数    
ObjectPool.prototype.getNumIdle = function() {    
    return this._idlePool.length;    
}    
// 销毁对象池及其中的所有对象    
// 如果对象池中的对象需要析构。那么必须实现poolableObjectFactory中的destroyObject方法，同时保证ObjectPool的destroy方法在需要的时候被调用到（例如Window的unload事件中）。    
ObjectPool.prototype.destroy = function() {    
    var factory = this._poolableObjectFactory;    
    function returnObject(object) {    
        if (factory.passivateObject) {    
            factory.passivateObject(object);    
        }    
    }    
    function destroyObject(object) {    
        if (factory.destroyObject) {    
            factory.destroyObject(object);    
        }    
    }       
    var activePool = this._activePool;    
    for (var i = 0; i         var object = activePool[i];    
        returnObject(object);    
        destroyObject(object);    
    }    
    var idlePool = this._idlePool;    
    for (var i = 0; i         var object = idlePool[i];    
        destroyObject(object);    
    }    
    this._idlePool = null;     
    this._activePool = null;     
    this._poolableObjectFactory = null;    
}   

上面代码中ObjectPool的构造参数poolableObjectFactory的声明如下: 

代码
// 注意: 这只是说明，不是真正的代码！    
var PoolableObjectFactory = {           
    makeObject: function() {}, // 创建一个新的对象。(必须声明)       

    activateObject: function(object) {}, // 当一个对象被激活时(即被借出时)触发的方法。(可选)    

    passivateObject: function(object) {}, // 当一个对象被钝化时(即被归还时)触发的方法。(可选)    

    destroyObject: function(object) {} // 销毁一个对象。(Optional)                                                                                                                               makeObject: function() {                                                                                                             
if (window.ActiveXObject){
return new ActiveXObject("Microsoft.XMLHTTP");
else {           return new XMLHttpRequest();                                                          ,                                                                                              passivateObject: function(xhr)                                                                           abort(); 
 } 
}; 
var pool = new ObjectPool(factory); // Create an object pool
// ......
var xhr = pool.borrowObject(); // Get an XMLHttpRequest object
xhr.onreadystatechange = function() {                                                                                 🎜 >};
xhr.open(method, url, true); 🎜>function test_pool() { 
 var factory = { 
 counter: 0, 

 makeObject: function() { 
  return {id: this.counter};                                                   

activateObject: function(object) {
object.activated = true;
},

passivateObject: function(object) {
object.activated = false; ​​​​🎜> };    
    var pool = new ObjectPool(factory);    
    // borrowObject object1    
    var object1 = pool.borrowObject();    
    assertEquals(object1.id, 1);    
    assertTrue(object1.activated);    
    assertEquals(factory.counter, 1);    
    assertEquals(pool.getNumActive(), 1);    
    assertEquals(pool.getNumIdle(), 0);    
    // borrowObject object2    
    var object2 = pool.borrowObject();    
    assertEquals(object2.id, 2);    
    assertTrue(object2.activated);    
    assertEquals(factory.counter, 2);    
    assertEquals(pool.getNumActive(), 2);    
    assertEquals(pool.getNumIdle(), 0);    
    // borrowObject object3    
    var object3 = pool.borrowObject();    
    assertEquals(object3.id, 3);    
    assertTrue(object3.activated);    
    assertEquals(factory.counter, 3);    
    assertEquals(pool.getNumActive(), 3);    
    assertEquals(pool.getNumIdle(), 0);    
    // returnObject object2    
    pool.returnObject(object2);    
    assertFalse(object2.activated);    
    assertEquals(factory.counter, 3);    
    assertEquals(pool.getNumActive(), 2);    
    assertEquals(pool.getNumIdle(), 1);    
    // returnObject object3    
    pool.returnObject(object3);    
    assertFalse(object3.activated);    
    assertEquals(pool.getNumActive(), 1);    
    assertEquals(pool.getNumIdle(), 2);    
    // returnObject object1    
    pool.returnObject(object1);    
    assertFalse(object1.activated);    
    assertEquals(pool.getNumActive(), 0);    
    assertEquals(pool.getNumIdle(), 3);         
    // destroy the pool    
    pool.destroy();    
    assertTrue(object1.destroyed);    
    assertTrue(object2.destroyed);    
    assertTrue(object3.destroyed);    
}