今天一同事问我Jscex怎么没有stop啊？

异步任务就像断线的风筝，我们没法让它说停就停，但是我们在放飞它之前，可以装个定时炸弹。

通常我们可以这样退出一个异步任务：

       var xxxAsync = eval(Jscex.compile("async", function () {while (condition) {....dosomething....        $await(Jscex.Async.sleep(1000));}}))

通过condition判断是否退出异步任务。或者等同于下面这种方式：

       var xxxAsync = eval(Jscex.compile("async", function () {while (true) {if(condition)break;....dosomething....        $await(Jscex.Async.sleep(1000));}}))

这两种方式的效果是一模一样的。

下面这种方式有个好处就是可以做一些初始化设置什么的：

       var xxxAsync = eval(Jscex.compile("async", function () {while (true) {if (condition) {//dosomethingbreak;}//dosomething      $await(Jscex.Async.sleep(1000));}}))

后来，同事又提供了一个要跳出循环的场景

       var xxxAsync = eval(Jscex.compile("async", function () {while (true) {for (i in XXX) {if (condition) { //要在这里跳出最外层的循环}}//dosomething      $await(Jscex.Async.sleep(1000));}}))

所以就只能这样：

       var xxxAsync = eval(Jscex.compile("async", function () {while (true) {for (i in XXX) {if (condition) {//要在这里跳出最外层的循环breakTag = true;}}if (breakTag) break;//dosomething      $await(Jscex.Async.sleep(1000));}}))

后来同事又提供了一个BT的场景：

       var countAsync1 = eval(Jscex.compile("async", function () {while (true) {for (i in XXX) {if (condition) {//要在这里跳出最外层的循环}}$await(Jscex.Async.sleep(1000));}}))var countAsync2 = eval(Jscex.compile("async", function () {while (true) {for (i in XXX) {if (condition) {//要在这里跳出最外层的循环}}     $await(Jscex.Async.sleep(1000));}}))var executeAsyncQueue = eval(Jscex.compile("async", function () {while (true) {$await(countAsync1())$await(countAsync2())$await(Jscex.Async.sleep(1000));}}))executeAsyncQueue().start();

相当于要在异步队列中跳出最最外层的循环。

我给出的方案还是breakTag

       var executeAsyncQueue = eval(Jscex.compile("async", function () {while (true) {$await(countAsync1())$await(countAsync2())if (breakTag) break;$await(Jscex.Async.sleep(1000));}}))

同理这个场景也用tag:

        var xxAsync = eval(Jscex.compile("async", function () {while (true) {//dosomething$await(xxxAsync())if (breakTag) break;$await(Jscex.Async.sleep("1000"));}}))var xxxAsync = eval(Jscex.compile("async", function () {if (condition) {breakTag = true;}$await(Jscex.Async.sleep("1000"));}))

所以：Jscex没有必要提供stop,你说呢？

Jscex.Async.Task = function (delegate) {this._delegate = delegate;this._handlers = [];this.status = "ready";
}
Jscex.Async.Task.prototype = {start: function () {if (this.status != "ready") {throw 'Task can only be started in "ready" status.';}var _this = this;this.status = "running";this._delegate["onStart"](function (type, value) {if (_this.status != "running") {throw ('Callback can only be used in "running" status.');}if (type == "success") {_this.result = value;_this.status = "succeeded";} else if (type == "failure") {_this.error = value;_this.status = "failed";} else if (type == "cancel") {_this.status = "canceled";} else {throw ("Unsupported type: " + type);}_this._notify();});},cancel: function () {if (this.status != "running") {throw 'Task can only be canceled in "running" status';}var onCancel = this._delegate["onCancel"];if (onCancel) onCancel();this._notify();},_notify: function () {var handlers = this._handlers;delete this._handlers;for (var i = 0; i < handlers.length; i++) {handlers[i](this);}},addListener: function (handler) {if (!this._handlers) {throw ('Listeners can only be added in "ready" or "running" status.');}this._handlers.push(handler);}
};