I have a number of threads that are performing a long runing task. These threads themselves have child threads that do further subdivisions of work. What is the best way for ... |
I have started a process in my Java code, this process take a very long time to run and could generate some output from time to time. I need to react ... |
What's a monitor referred to the concurrent programming in Java?
When I read that "every object has associated a monitor" what does it meaning?
Is it a special object?
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I am trying to debug some C/Java bindings that use some custom refcounting/locking. I would like to have the JVM print a message every time a given object has its monitor ... |
I read this in Java language Spec 17.1:
"Each object in Java is associated
with a monitor, which a thread can
lock or unlock."
Why necessarily? Doesn't that make ... |
and excuse the lack of knowledge on multithreaded apps, but I am new to the field.
Is there a pattern or common used methodology for monitoring the 'job completion' or 'job status' ... |
All I want to know is that when a thread enters out of a lock, does it means it "ends" or just that it has finished using that function or code ... |
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I'm trying to monitor the file content and adding any new line to JTextArea. I created thread, which monitor the file, but when the Scanner object reachs the end of file ... |
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Summary: I need to create a child thread/process that tries to reach an outside URL, get some info, and return. That child needs to be monitored so that if it doesn't return with results within five seconds, it parent gives up and goes on. Now, with that in mind, here's the situation: I have a servlet that creates a web page ... |
Hi! I'm looking for an example for a workerThread being monitored by another thread (monitorThread). The monitor's sole job is to restart(set isRunning=true) the workerThread should the workerThread's isRunning==false. Anybody know of any? BTW -- This is my first post -- I'm a Sun certified JP and have learned much from the discussions here -- Thanks |
12. Monitor coderanch.comMonitor is infact an Object that can block and allow a thread(s) to run. For this purpose Monitor provides every Object a lock and this lock is controlled by atmost one Thread at a particular time. And also putting synchronized keyword before a method decleration or a block just makes the lock of the object containing that code to be acquired ... |
Hello, Monitoring and locking an object are essentially the same thing. I think of monitor as the process by which a thread determines if it can gain a lock on an object. In other words, you can use the lock variable as a way to monitor an object to see if it is available to your thread. The Object class has ... |
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Hi, Page 214 in RHE has the code for Consumer3, but the code in that version of the program isn't intended to call properly formed thread methods. Below, is my version of Consumer3 calling the methods in Mailbox3. How am I going to call the synchronized methods in Mailbox3? I can't call them with an instance of Thread because Thread doesn't ... |
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when you call wait(), the current object's wait() method is invoked, ie, you are calling this.wait(). It looks like the current object doesn't have a monitor associated with it. You haven't obtained a lock on the current object previous to calling wait() which you must do. Since you've only provided snippets of code it's really impossible to suggest how to fix ... |
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b)you have wrigte,it is my homework,but i work on it. a)i do not understand do I need 2 threads(wolfes and sheeps) or 3(one for the boat)?(because using semaphore in c i have 3 proceses)I made example with two threads but it's work strange. I znderstand ProducerConsumer prog,but i just can't understood this.So please,if you want and can,give me some help. |
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Hi, In the foll' code, iam sending 5 threads into waiting pool and like to observe the order of their notification. But Im getting Illegal Monitor State Exception. what's wrong? class NotifyLab { static class Rendezvous { synchronized public void hurryUpAndWait() { System.out.println("*****-------****"); try { wait(); } catch(Exception e) { System.out.println(e); } } synchronized public void not() { Thread.currentThread().notify(); } } ... |
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Hi, I'm reading 'Modern Operating Systems' by Tanenbaum and I want to map the inner process data structures to the java language. My questions: Do Semaphores or Mutexes keep track of their callers ? If i want to implement a Semaphore do I need to store the current executing Thread in an instance variable of the Semaphore ? Because if not ... |
Ranchers, I need a Monitor Thread monitoring a bunch of Worker Threads. Now what is the best to implement Monitoring? Option 1> Monitor is constantly iterating a Thread collection to find out who's running... If a Worker completed a task successfully then do something? Option 2> Monitor is sleeping waiting to be notified by a Worker Thread? If so is there ... |
There have been many discussions about this. I have implemented the Jakarta Common threadpool and it works, but I now need more options. ThreadPool threadPool = new DefaultThreadPool(3); while ( i != 5){ threadPool.invokeLater(new MyObject); // This will call the run method } public void run(){ //do something.... } ******************* Other notes about my code: 1) My class implements Runnable My ... |
Originally posted by Johnson David: HI, I have the fallowing doubt what is the difference between a Monitor and a Semaphore ? thanks in advanced, Johnson These are just different terminologies. A Monitor is best regarded as a generic term for a synchronization lock, although I have seen cases where it is used to refer to the condition variable functionality too. ... |
The following is my effort to differentiate Thread Monitors and priorities between them. Is this sample code infering more than that? This my effort is trying to answer an interview question. The question: In a class with two sync methods and one static method with sync code block, explain the monitors, priorities and dependencies? import java.lang.*; public class MyClass { private ... |
So basically you have a homework assignment to explain these concepts using example code, and you think we're gonna do it for you? Sorry if I have misunderstood the situation, but I can't see another explanation. If you have some specific questions about these concepts, then please take the time to compose something more appropriate. [ October 18, 2007: Message edited ... |
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Hi, I want a thread say first thread monitored by another thread say second thread . When the first thread stops i want to restart the first thread with the help of second thread. i.e second thread restarts the first one when it stops and the calls the run() methos of the first thread ... please provide me some suggestions . ... |
Hello to all, I am try to run a RMI application in which the server call backs to the client on some event occur on server side. my client side code is public class client { public static void main(String a[]) { client clnt=new client(); MyNewThread mnt=new MyNewThread("newThread",clnt); mnt.start(); } } the MyNewThread.java contains public class MyNewThread extends Thread implement CallBackMe ... |
Hi All, I have a server application which runs(spawns) multiple threads for running various tasks, and many of them run the same task for various clients. I want all the threads doing the same task to occupy same priority and memory (dont want one client to use up my jvm too much). so am thinking of having some kind of a ... |
Hi All, I have a calculation which is to be performed multiple times ( I will not know in advance on how many times to be performed, as the current flow is such that it checks for the details and starts a thread to do the calculation whenever required ). But, I do want to advance to the next step after ... |
During my study on Java threads, I find many references to a "object monitor". I have a hard time, trying to fit in the "object monitor" into the complete multi-threaded picture. So far I have learned the following facts that: - Every object has its own "monitor" - A monitor watches over an object / the thread - A monitor handles ... |
Really, Todd, if you have a question about what Bill Venners wrote, you should ask him that question. But it's helpful that we now have a background for your question. That might make it easier to answer. But the other thing we need is background on you. I get the impression that you're a beginner in the threading area. If that's ... |
Hello java world! I create a thread that call a synchronized method and also I call this method from the main thread, immediately after i started the created thread. I want the created thread to gain the monitor always first (in front of the main thread). I dont't want to call thread.join() to wait after my thread. How can I achive ... |
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Hi all, from my Web application i launch several threads to perform external searches and when they finish nothing special must happen. I have also a java class with a main method which i must launch periodically from a cron which performs also these external searches using these threads (in fact, the java code is the same ..) My problem is ... |