fabrication的拦截器Interceptors简介

// registers the interceptor with save notification with extra parameters
registerInterceptor("save", MyInterceptor, {foo:"bar"});

Interceptors的实现

拦截类的处理类(前面提及的clazz)，必须继承自AbstractInterceptor类，并实现intercept方法。

当注册的Notifications被发送时(使用sendNotification或是routerNotification方法进行发送)，

拦截器会调用该处理类的intercept方法，这些方法中可以直接使用的对象有：

notification：被拦截的notification对象

parameters：拦截器注册时传入的可选参数

processor：对外提供的几种方法，忽略、跳过或中止该notification的广播，包含三个方法<proceed|abort|skip>

proceed：允许notification继续进行广播，可以使用新的notification替换当前的notification。

skip：如果所有对该notification的拦截器处理已经完成，就直接调用完成方法。不然就再调用该notification的其它拦截器实例

abort：直接中止该notification的广播，并立即调用完成方法。

在框架源码中可以看到上述三个方法中的实现：

1: public function getNotification():INotification {   2:     return notification;   3: }   4:     5: /**   6:  * Adds a interceptor to the list of interceptors for the current notification.   7:  *    8:  * @param interceptor The interceptor object to register.   9:  */  10: public function addInterceptor(interceptor:IInterceptor):void {  11:     interceptor.processor = this;              12:     interceptors.push(interceptor);  13: }  14:    15: /**  16:  * Removes the specified interceptor from the list of interceptors.  17:  *   18:  * @param interceptor The interceptor object to remove.  19:  */  20: public function removeInterceptor(interceptor:IInterceptor):void {  21:     var index:int = interceptors.indexOf(interceptor);  22:     if (index >= 0) {  23:         interceptors.splice(index, 1);  24:         interceptor.dispose();  25:     }  26: }  27:    28: /**  29:  * Runs all interceptors registered with this NotificationProcessor.  30:  */  31: public function run():void {  32:     var n:int = interceptors.length;  33:     var interceptor:IInterceptor;  34:     for (var i:int = 0; i < n; i++) {  35:         interceptor = interceptors[i];  36:           37:         interceptor.notification = notification;  38:         interceptor.intercept();  39:     }  40: }  41:    42: /**  43:  * Sends a proceed event so that the notification can be send to the rest of  44:  * the PureMVC actors. Flags this instance as complete to ignore other interceptors.  45:  * Also sends a finish event to indicate that the processor can be disposed.  46:  *   47:  * @param note The notification to proceed with. If null the current notification object is used.  48:  */  49: public function proceed(note:INotification = null):void {  50:     if (!finished) {  51:         dispatchEvent(new NotificationProcessorEvent(NotificationProcessorEvent.PROCEED, note));  52:         finish();  53:     }  54: }  55:    56: /**  57:  * Sends an abort event. Flags this instance as complete to ignore other interceptors.  58:  * Also sends a finish event to indicate that the processor can be disposed.  59:  */  60: public function abort():void {  61:     if (!finished) {  62:         dispatchEvent(new NotificationProcessorEvent(NotificationProcessorEvent.ABORT));  63:         finish();  64:     }  65: }  66:    67: /**  68:  * If all interceptors have been skipped then sends a finish event to indicate  69:  * that the processor can be disposed.  70:  */  71: public function skip():void {  72:     if (!finished && ++skipCount == interceptors.length) {  73:         finish();  74:     }  75: }  76:    77: /**  78:  * Flags the notification as finished and sends a finish event.  79:  */  80: public function finish():void {  81:     finished = true;  82:     dispatchEvent(new NotificationProcessorEvent(NotificationProcessorEvent.FINISH));  83: }