Jscex没有xxxAsync().stop()怎么办？

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：

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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：

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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：

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

 

后来，同事又提供了一个要跳出循环的场景

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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：

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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：

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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

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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:

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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？

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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);     } };