Re: [aerogear-dev] AGDROID-11

Hi, Some comments inline. And if that sounds good, I will issue a PR based on this direction, and more reviews/additions/changes would then be easier. wdyt?

Regards. --- Yavuz Selim Yilmaz SUNY at Buffalo Computer Science and Engineering PhD Candidate On Aug 15, 2013, at 1:46 PM, Summers Pittman <supittma(a)redhat.com <mailto:supittma@redhat.com>> wrote: > On 08/15/2013 12:23 PM, Yavuz Selim YILMAZ wrote: >> So, if I get it right, each pipe will have it's runnable list. When >> the pipe is cancelled, it'll remove all waiting runnable's from >> threadpoolexecutor, and cancel the ones currently running. Am I right? > Not exactly. When the Runnable is finished, it removes itself form > the thread pool executor. You will need some other collection which > is modified when a pipe operation begins or completes. So, when I cancel currently running runnable's, they'll (automatically) be removed from the thread pool executor. But, there might be some awaiting runnable's in the thread pool executor too, or there can't be? I feel like, considering two consecutive pipe request, one will most likely be waiting in the thread pool executor while the other is running (or at least there might be such cases depending on the system resources etc.)

>> >> If so, then what'd be the proper way of cleaning the successfully >> completed runnable's from pipe's list? > For example RestAdapter.java#131: > > if (exception == null) { > runnableCollection.remove(this); > callback.onSuccess(this.result); > } else { > runnableCollection.remove(this); > callback.onFailure(exception); > } > > Would be my first guess. In this case, since the runnable will be a static nested class, it'll need a reference to the outer (i.e. RestAdapter) class. Am I right?

> >> >> For the loader part, I'll check on how to implement your suggestion, >> >> Regards, >> >> --- >> Yavuz Selim Yilmaz >> SUNY at Buffalo >> Computer Science and Engineering >> PhD Candidate >> >> On Aug 15, 2013, at 10:54 AM, Summers Pittman <supittma(a)redhat.com >> <mailto:supittma@redhat.com>> wrote: >> >>> Wow you don't make this easy on us ;) >>> >>> Killing the thread/thread pool is probably a bad idea. It may be >>> cleaner to make the anonymous runner classes in RestAdatper into >>> static classes which implement Runnable and provide a cancel >>> method. In the RestAdapter you could do some bookkeeping to >>> provide references to the Threads so you can call cancel on each >>> one which is currently running. >>> >>> Also, the LoaderAdapters will need a different solution (but theirs >>> is MUCH easier, you just call cancelLoader and implement onCancel >>> in the Loader implementations). >>> >>> Summers >>> >>> PS bookkeeping is one of my favorite words. >>> >>> >>> On 08/14/2013 03:36 PM, Yavuz Selim YILMAZ wrote: >>>> Hi all, >>>> >>>> I am working on AGDROID-11 >>>> [https://issues.jboss.org/browse/AGDROID-11]. As suggested on the >>>> JIRA, I started with investigating how AeroGear iOS handles pipe >>>> cancel operation. >>>> >>>> ----------------------------------------------------------------------- >>>> ---- Skip if you don't want to verify my iOS tracking ---- >>>> ----------------------------------------------------------------------- >>>> ------------------------------ Start --------------------------------- >>>> ----------------------------------------------------------------------- >>>> >>>> First, here is what I could track on the iOS side (please correct >>>> me if there's any mistake): >>>> >>>> - AGRESTPipe cancel method simply calls the cancelAllOperations on >>>> its restClient's operationQueue [1]. >>>> - AGRESTPipe's restClient is a AGHttpClient [2]. >>>> - AGHttpClient is a AFHttpClient [3]. >>>> - AFHttpClient's operationQueue is a NSOperationQueue [4]. >>>> - Calling cancelAllOperations on NSOperationQueue sends cancel >>>> message to all Operations in the queue [5]. If the operation is >>>> still in the queue (waiting to be executed), they are not being >>>> executed. If the operation is alread started to it's execution, >>>> it's up to the "Operation" how to respond to cancel message. >>>> - Sending cancel message to operations sets their isCancelled >>>> flag. Any custom NSOperation extension is recommended to handle >>>> this cancel operation [6]. >>>> - AGHttpClient creates the operation by calling >>>> HTTPRequestOperationWithRequest [7], which is AFHttpClient method. >>>> It creates either custom (AFImage, AFJSON, AFPropertyList, AFXML) >>>> operation [8] or AFHttpRequestOperation [9]. All custom operations >>>> are AFHttpRequestOperation, which is a AFURLConnectionOperation [10]. >>>> - AFURLConnectionOperation implements cancel method [11] and >>>> simply cancels the operation's NSURLConnection, the connection is >>>> cancelled and no delegate is called [12]. >>>> - Then AFURLConnectionOperation calls its delegate method manually >>>> to finish the operation [13]. >>>> - The delegate handles the case [14] and finishes the operation [15]. >>>> >>>> ----------------------------------------------------------------------- >>>> ------------------------------- End --------------------------------- >>>> ----------------------------------------------------------------------- >>>> ---- Skip if you don't want to verify my iOS tracking ---- >>>> ----------------------------------------------------------------------- >>>> >>>> >>>> >>>> Simply, what I understand is, operation itself is responsible to >>>> handle the cancel message sent by any pipe implementation. And on >>>> the Android side, the operations are runnables [16, 17, 18, 19] as >>>> far as I could interpret. So, these runnables should be able to >>>> handle cancel messages which means they should catch or throw the >>>> thrown InterruptedException. >>>> >>>> So, the problem is, find a way to send cancel message to the >>>> tasks, and handle the cancel message on the tasks. >>>> >>>> >>>> HOW TO SEND CANCEL MESSAGE TO THE TASKS? >>>> >>>> 1ST PROPOSAL: >>>> >>>> RestAdapter is using ThreadPoolExecutor [20]. So, one way to send >>>> cancel message to all running and queued runnables is to call >>>> shutDownNow on the ThreadPoolExecutor [21]. It has some >>>> limitations. First, shut down destroys the ThreadPoolExecutor, so >>>> it needs to be recreated. Second, the current ThredPoolExecutor is >>>> static, means it will cancel all pipes if it is shut down, so it >>>> needs to be an instance variable instead of static. >>>> >>>> >>>> 2ND PROPOSAL: >>>> >>>> Instead of calling THREAD_POOL_EXECUTOR.execute(), if we call >>>> THREAD_POOL_EXECUTOR.submit() [22], then it returns a Future >>>> representing the task. Future has cancel() [23], which prevents >>>> running the task if it is not started, and interrupts the task if >>>> it is currently running. Therefore, if we have a collection of >>>> <Future> in RestAdapter (i.e. pipe), then we can cancel the >>>> operations by iterating over the collection and calling cancel() >>>> on each Future. In this case, at some point, we need to clean >>>> <Future> collection to get rid of the already cancelled tasks. >>>> >>>> >>>> >>>> HOW TO HANDLE THE CANCEL MESSAGE ON THE TASKS? >>>> >>>> I could only come up with a single solution, which is, adding >>>> another catch block to each of the runnables [16, 17, 18, 19]. >>>> Here is what it will look like: >>>> >>>> try { >>>> this.result = ... >>>> } catch (InterruptedException e) { >>>> return; // don't call the callbacks, may need to check the >>>> cause of the interrupt??? >>>> } catch (Exception e) { >>>> Log.e(TAG, e.getMessage(), e); >>>> this.exception = e; >>>> } >>>> >>>> >>>> >>>> So, I would like to hear what you think about my solution, and if >>>> you have any corrections, better solutions, comments, anything... >>>> All are most welcome. >>>> >>>> >>>> Kind regards, >>>> >>>> >>>> >>>> >>>> >>>> --- REFERENCES --- >>>> [1] >>>> https://github.com/aerogear/aerogear-ios/blob/master/AeroGear-iOS/AeroGea... >>>> [2] >>>> https://github.com/aerogear/aerogear-ios/blob/master/AeroGear-iOS/AeroGea... >>>> [3] >>>> https://github.com/aerogear/aerogear-ios/blob/master/AeroGear-iOS/AeroGea... >>>> [4] >>>> https://github.com/AFNetworking/AFNetworking/blob/master/AFNetworking/AFH... >>>> [5] >>>> http://developer.apple.com/library/ios/DOCUMENTATION/Cocoa/Reference/NSOp... >>>> [6] >>>> http://developer.apple.com/library/mac/documentation/Cocoa/Reference/NSOp... >>>> [7] >>>> https://github.com/aerogear/aerogear-ios/blob/master/AeroGear-iOS/AeroGea... >>>> [8] >>>> https://github.com/AFNetworking/AFNetworking/blob/master/AFNetworking/AFH... >>>> [9] >>>> https://github.com/AFNetworking/AFNetworking/blob/master/AFNetworking/AFH... >>>> [10] >>>> https://github.com/AFNetworking/AFNetworking/blob/master/AFNetworking/AFH... >>>> [11] >>>> https://github.com/AFNetworking/AFNetworking/blob/master/AFNetworking/AFU... >>>> [12] >>>> http://developer.apple.com/library/mac/documentation/Cocoa/Reference/Foun... >>>> [13] >>>> https://github.com/AFNetworking/AFNetworking/blob/master/AFNetworking/AFU... >>>> [14] >>>> https://github.com/AFNetworking/AFNetworking/blob/master/AFNetworking/AFU... >>>> [15] >>>> https://github.com/AFNetworking/AFNetworking/blob/master/AFNetworking/AFU... >>>> >>>> [16] >>>> https://github.com/aerogear/aerogear-android/blob/master/src/org/jboss/ae... >>>> [17] >>>> https://github.com/aerogear/aerogear-android/blob/master/src/org/jboss/ae... >>>> [18] >>>> https://github.com/aerogear/aerogear-android/blob/master/src/org/jboss/ae... >>>> [19] >>>> https://github.com/aerogear/aerogear-android/blob/master/src/org/jboss/ae... >>>> [20] >>>> https://github.com/aerogear/aerogear-android/blob/master/src/org/jboss/ae... >>>> [21] >>>> http://developer.android.com/reference/java/util/concurrent/ThreadPoolExe... >>>> <http://developer.android.com/reference/java/util/concurrent/ThreadPoolExe... >>>> [22] >>>> http://developer.android.com/reference/java/util/concurrent/AbstractExecu... >>>> <http://developer.android.com/reference/java/util/concurrent/AbstractExecu... >>>> [23] >>>> http://developer.android.com/reference/java/util/concurrent/Future.html#c... >>>> <http://developer.android.com/reference/java/util/concurrent/Future.html#c... >>>> >>>> --- >>>> Yavuz Selim Yilmaz >>>> SUNY at Buffalo >>>> Computer Science and Engineering >>>> PhD Candidate >>>> >>>> >>>> >>>> _______________________________________________ >>>> aerogear-dev mailing list >>>> aerogear-dev(a)lists.jboss.org >>>> https://lists.jboss.org/mailman/listinfo/aerogear-dev >>> >>> _______________________________________________ >>> aerogear-dev mailing list >>> aerogear-dev(a)lists.jboss.org <mailto:aerogear-dev@lists.jboss.org> >>> https://lists.jboss.org/mailman/listinfo/aerogear-dev >> >> >> >> _______________________________________________ >> aerogear-dev mailing list >> aerogear-dev(a)lists.jboss.org >> https://lists.jboss.org/mailman/listinfo/aerogear-dev > > _______________________________________________ > aerogear-dev mailing list > aerogear-dev(a)lists.jboss.org <mailto:aerogear-dev@lists.jboss.org> > https://lists.jboss.org/mailman/listinfo/aerogear-dev _______________________________________________ aerogear-dev mailing list aerogear-dev(a)lists.jboss.org https://lists.jboss.org/mailman/listinfo/aerogear-dev