;(function($) {
$.ajaxQueue = {
// 管理ajax請求的隊列
requests: new Array(),
// 把待發(fā)送的ajax請求加入隊列
offer: function(options) {
var _self = this,
// 對complete，beforeSend方法進行“劫持”，加入隊列處理方法poll
xhrOptions = $.extend({}, options, {
// 如果請求完成，發(fā)送下一個請求
complete: function(jqXHR, textStatus) {
if(options.complete)
options.complete.call(this, jqXHR, textStatus);
_self.poll();
},
// 如果請求被取消，繼續(xù)發(fā)送下一個請求
beforeSend: function(jqXHR, settings) {
if(options.beforeSend)
var ret = options.beforeSend.call(this, jqXHR, settings);
if(ret === false) {
_self.poll();
return ret;
}
}
});
this.requests.push(xhrOptions);
if(this.requests.length == 1) {
$.ajax(xhrOptions);
}
},
// 用FIFO方式發(fā)送ajax請求
poll: function() {
if(this.isEmpty()) {
return null;
}
var processedRequest = this.requests.shift();
var nextRequest = this.peek();
if(nextRequest != null) {
$.ajax(nextRequest);
}
return processedRequest;
},
// 返回隊列頭部的ajax請求
peek: function() {
if(this.isEmpty()) {
return null;
}
var nextRequest = this.requests[0];
return nextRequest;
},
// 判斷隊列是否為空
isEmpty: function() {
return this.requests.length == 0;
}
}
})(jQuery);