synchronization

问题 This question already has answers here : Why are empty catch blocks a bad idea? [closed] (20 answers) Closed 2 years ago . I have 3 very small classes. The main class: import java.io.*; public class ConnectionManager { public static void main(String argv[]) { try { PipedOutputStream pout = new PipedOutputStream(); PipedInputStream pin = new PipedInputStream(pout); Sender s = new Sender(pout, true); Receiver r = new Receiver(pin, true); System.out.println("Starting threads"); s.start(); r

问题 This question already has answers here : Why are empty catch blocks a bad idea? [closed] (20 answers) Closed 2 years ago . I have 3 very small classes. The main class: import java.io.*; public class ConnectionManager { public static void main(String argv[]) { try { PipedOutputStream pout = new PipedOutputStream(); PipedInputStream pin = new PipedInputStream(pout); Sender s = new Sender(pout, true); Receiver r = new Receiver(pin, true); System.out.println("Starting threads"); s.start(); r

问题 I am using node js and making a call to spotify API and receive the response in body object, as shown in below code: var options = { url: 'https://api.spotify.com/v1/me', headers: { 'Authorization': 'Bearer ' + access_token }, json: true }; request.get(options, function(error, res, body) { console.log(body) }); This gives me output: But now when I try to access the body object outside the function I get undefined. I think the problem is that I am making an asynchronous call and so before the

问题 I am using node js and making a call to spotify API and receive the response in body object, as shown in below code: var options = { url: 'https://api.spotify.com/v1/me', headers: { 'Authorization': 'Bearer ' + access_token }, json: true }; request.get(options, function(error, res, body) { console.log(body) }); This gives me output: But now when I try to access the body object outside the function I get undefined. I think the problem is that I am making an asynchronous call and so before the

问题 I have provided with a sample JSON file (for testing purpose I haven't early access to the web service). after loading the file and converting to NSDictionary how can I use that dictionary and sync my data base? all the tutorials and samples I've read use web service I have created my mapping for all of the objects and applied their relationship. an example: + (RKEntityMapping *) mapTableInManagedObjectStore:(RKManagedObjectStore *)managedObjectStore { RKEntityMapping *tableMapping =

问题 So the description of the exercise: You have this restaurant in which there are N points where you can ask for a portion of fries. Each point has M portions. There is 1 frycheff. When an order-point has 2 portions, it warns the cheff that it needs a refill. The cheff delivers the portions in order of FIFO. We made this pseudo-code: init { Semafoor[] mutex; Condition[] cond_point = new Condition[N]; int[] portions = new int[N]; ArrayList<int> waitline = new ArrayList<int>(); for(int i = 0; i <

问题 Calling channel.position on an ENTER_FRAME event, I notice that it's not being updated every frame, but it looks more like every frame and a half. var sound:Sound = new Sound(new URLRequest('music.mp3')); var channel:SoundChannel = sound.play(); // assume the sound is completely, // totally, 100% loaded addEventListener(Event.ENTER_FRAME, function(e:Event):void{ trace( "Position : " + channel.position + " - Frame : " + int(channel.position / 30)); }); will result in something along the lines

问题 I am currently implementing an application which relies on Firebase data before it can continue. However, I often (unless I deliberately wait) get the result Cannot read property [property] of null . I very much suspect that this is because the firebase request could not be made before I call this object. Now I am looking for methods to implement a rendez-vous, or a barrier, really anything that implements a checkpoint where all firebase data are received, before it continues. Is there

问题 I was looking over some topics that describes the difference between mutex and binary semaphore. In many topics it is stated that semaphore act as a signalling mechanism i.e if a thread has locked a semaphore then another thread can unlock(release) the semaphore(acting as signal). But in case of mutex only the thread that locks the mutex can unlock it .It can't be unlocked by any other thread and if other thread tries to unlock it this will return error. I have tried writing a code that uses

问题 I am trying to copy all table data from server to my local database, like INSERT INTO [.\SQLEXPRESS].[Mydatabase]..MYTable SELECT * FROM [www.MYSite.com].[Mydatabase]..MYTable www.MYSite.com having SQL LOGIN ID XYZ AND PASSWORD 1234 but I get an error: Could not find server 'www.MYSite.com' in sys.servers. Verify that the correct server name was specified. If necessary, execute the stored procedure sp_addlinkedserver to add the server to sys.servers. I want to copy all the data from Mytable