synchronization

问题 This works: int _counter; readonly SemaphoreSlim _semaphore = new SemaphoreSlim(1, 1); async void Button_Click(object sender, RoutedEventArgs e) { if (_semaphore.Wait(0)) { Title = $"{ ++_counter}"; await Task.Delay(1000); // simulate work Title = $"{ --_counter}"; _semaphore.Release(); } } After first click further buttons clicks are ignored until work is finished. Tittle can be 1 or 0 . And this doesn't work void Button_Click(object sender, RoutedEventArgs e) { if (_semaphore.Wait(0)) {

问题 I seem to have a small problem. I have an Air Traffic Control Application, with two runways which I am to synchronize in java. This is to be done because, if there is a plane two that lands while plane one is in the process of landing, it(plane two) does not have to wait but can quickly move to the runway two to land. I have successfully synchronized one runway and I use one ArrayList to store the plane details and the landing works, however landing of plane two will have to wait(about 5

问题 I was wondering if synchronize (lock) { ... } Where lock is an instance of java.util.concurrent.locks.Lock , treats lock like any other object or as the try-finally idiom i.e. lock.lock(); try { ... } finally { lock.unlock(); } 回答1: Lock documentation: Note that Lock instances are just normal objects and can themselves be used as the target in a synchronized statement. Acquiring the monitor lock of a Lock instance has no specified relationship with invoking any of the lock() methods of that

问题 I want to store currently running Jupyter notebook name in python variable. I create 2 cells from IPython.display import display,Javascript Javascript('IPython.notebook.kernel.execute("notebook_name = " + "\'"+IPython.notebook.notebook_name+"\'");') and notebook_name This works fine if I execute cells one after another, but I mostly execute cells with "run all cells" command, and in this case I get the error: NameError: name 'notebook_name' is not defined I get the same error if I unite

问题 Context A mobile application can add/edit/delete a customer in it's own offline database. A web application can also add/edit/delete a customer in the master database on a web server. The mobile application will try to sync it's database with the master database every X hours, provided it has an internet connection available. Case Mobile application edits customer A in its offline database Web application edits customer A in the master database Mobile application gains access to internet and

问题 I am having problem dealing with synchronization java threads, applying wait and notify.. I want to figure out how could I implement these in a program where I can print out the answer alternately.. for example person1 will count numbers 1-5 as well as person2, the output should be like this. person1 count 1 person2 count 1 person1 count 2 person2 count 2 person1 count 3 person2 count 3 person1 count 4 person2 count 4 person1 count 5 person2 count 5 Thanks guys. 回答1: You could do this easily

问题 This question already has answers here : How do I return the response from an asynchronous call? (36 answers) Closed 2 years ago . I am trying to run to promises (which make some rest API calls on each). Based on the result of the two promises, use the third function to process the data. Also, the functions running in sequence can be changing. So I made them in a dynamic way of constructing promise. However, the promises seem to be starting without the previous one ending. Here is a

问题 I'm using SQL Server 2008, visual studio 2008, linq, ado.net in my current project. this project is implemented in web and desktop. now my problem is with synchronization of data between web db and desktop db. here synchronization is as follow: new data inserted in client is synced to server. updated data in client is synced to server. here let me show you my table structure. let us suppose my table name is "customer" with fields customer ................... customerno, bigint, primary key,

问题 I've got from someone this example with a multithreaded server on android: http://tutorials.jenkov.com/java-multithreaded-servers/singlethreaded-server.html But I have a few difficulties in understanding a part of the code: while(! isStopped()) { Socket clientSocket = null; try { clientSocket = this.serverSocket.accept(); } catch (IOException e) { if (isStopped()) { System.out.println("Server Stopped.") ; return; } throw new RuntimeException("Error accepting client connection", e); } What I

问题 Considering the example: function returnValue () { return somePromise.then ( function (someThing) { return { sucess: true, data: someThing } }, function (someError) { return { sucess: false, data: someError } } ) } Console.log (returnValue ()) What should I do so that I actually have "someThing" or "someError"? And not a Promise pending? Just to note ... when I write a code like this within "Meteor.methods" it works exactly as I would like, that is, it returns a value that I return to the