function Asynchronous( ) {
    this._xmlhttp = new FactoryXMLHttpRequest();
    this.username = null;
    this.password = null;
}

function Asynchronous_call( action, url, data) {
    var instance = this;
    this._xmlhttp.open( action, url, true, this.username, this.password);
    this._xmlhttp.setRequestHeader("If-Modified-Since", "Sat, 1 Jan 2000 00:00:00 GMT"); 
    this.openCallback( this._xmlhttp);
    this._xmlhttp.onreadystatechange = function() {
        switch( instance._xmlhttp.readyState) {
        case 1:
            instance.loading();
            break;
        case 2:
            instance.loaded();
            break;
        case 3:
            instance.interactive();
            break;
        case 4:
            if( instance.complete) {
                try {
                    instance.complete(instance._xmlhttp.status, instance._xmlhttp.statusText,
                            instance._xmlhttp.responseText, instance._xmlhttp.responseXML);
                }
                catch (e) {        
                alert(e);        
                }
            }
            break;
        }
    }
    try {
        this._xmlhttp.send( data);
    }
    catch( e) {
    alert(e);
    }
}

function Asynchronous_get( url) {
    this.call( "GET", url, null);
}

function Asynchronous_put( url, mimetype, datalength, data) {
    this.openCallback = function( xmlhttp) {
        xmlhttp.setRequestHeader( "Content-type", mimetype);
        xmlhttp.setRequestHeader( "Content-Length", datalength);
    }
    this.call( "PUT", url, data);
}

function Asynchronous_delete( url) {
    this.call( "DELETE", url, null);
}

function Asynchronous_post( url, mimetype, datalength, data) {
    var thisReference = this;
    this.userOpenCallback = this.openCallback;
    this.openCallback = function( xmlhttp) {
        xmlhttp.setRequestHeader( "Content-type", mimetype);
        xmlhttp.setRequestHeader( "Content-Length", datalength);
        thisReference.userOpenCallback( xmlhttp);
        thisReference.openCallback = thisReference.userOpenCallback;
    }
    this.call( "POST", url, data);
}

function Asynchronous_openCallback( obj) { 
}
function Asynchronous_loading() {
}
function Asynchronous_loaded() {
}
function Asynchronous_interactive() {
}
function Asynchronous_complete( status, statusText, responseText, responseHTML) {
}

Asynchronous.prototype.openCallback = Asynchronous_openCallback;
Asynchronous.prototype.loading = Asynchronous_loading;
Asynchronous.prototype.loaded = Asynchronous_loaded;
Asynchronous.prototype.interactive = Asynchronous_interactive;
Asynchronous.prototype.complete = Asynchronous_complete;
Asynchronous.prototype.get = Asynchronous_get;
Asynchronous.prototype.put = Asynchronous_put;
Asynchronous.prototype.del = Asynchronous_delete;
Asynchronous.prototype.post = Asynchronous_post;

Asynchronous.prototype.call = Asynchronous_call;