pausethread.html
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(Java Developers Almanac Example)
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<h3>
e96.
Pausing a Thread</h3>
<P> The proper way to temporarily pause the execution of another
thread is to set a variable that the target thread checks
occasionally. When the target thread detects that the variable is
set, it calls <code>Object.wait()</code>. The paused thread can then be woken up by
calling its <code>Object.notify()</code> method.
<P> Note: <code>Thread.suspend()</code> and <code>Thread.resume()</code> provide
methods for pausing a thread. However, these methods have been
deprecated because they are very unsafe. Using them often results in
deadlocks. With the approach above, the target thread can ensure that
it will be paused in an appropriate place.
<pre>
// Create and start the thread
<font color="#0066ff"><i>MyThread</i></font> thread = new <font color="#0066ff"><i>MyThread</i></font>();
thread.start();
while (true) {
// Do work
// Pause the thread
synchronized (thread) {
thread.pleaseWait = true;
}
// Do work
// Resume the thread
synchronized (thread) {
thread.pleaseWait = false;
thread.notify();
}
// Do work
}
class <font color="#0066ff"><i>MyThread</i></font> extends Thread {
boolean pleaseWait = false;
// This method is called when the thread runs
public void run() {
while (true) {
// Do work
// Check if should wait
synchronized (this) {
while (pleaseWait) {
try {
wait();
} catch (Exception e) {
}
}
}
// Do work
}
}
}
</pre>
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Related Examples
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e92. <a class="eglink" href="BasicThread.html?l=rel">
Creating a Thread
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e93. <a class="eglink" href="StopThread.html?l=rel">
Stopping a Thread
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e94. <a class="eglink" href="IfStopped.html?l=rel">
Determining When a Thread Has Finished
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e95. <a class="eglink" href="Sleep.html?l=rel">
Pausing the Current Thread
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e97. <a class="eglink" href="IfLocked.html?l=rel">
Determining If the Current Thread Is Holding a Synchronized Lock
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e98. <a class="eglink" href="DaemonThread.html?l=rel">
Allowing an Application with Live Threads to Exit
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e99. <a class="eglink" href="ListThreads.html?l=rel">
Listing All Running Threads
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e100. <a class="eglink" href="TLocal.html?l=rel">
Using a Thread-local Variable
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e101. <a class="eglink" href="GetStack.html?l=rel">
Getting the Stack Trace of an Exception
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e102. <a class="eglink" href="WorkQueue.html?l=rel">
Implementing a Work Queue
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See also:
<a class="eglink" href="/egs/java.lang/pkg.html?l=rel#Arrays">
Arrays
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<a class="eglink" href="/egs/java.lang/pkg.html?l=rel#Assertions">
Assertions
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Classes
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<a class="eglink" href="/egs/java.lang/pkg.html?l=rel#Commands">
Commands
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<a class="eglink" href="/egs/java.lang/pkg.html?l=rel#Numbers">
Numbers
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<a class="eglink" href="/egs/java.lang/pkg.html?l=rel#Objects">
Objects
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<a class="eglink" href="/egs/java.lang/pkg.html?l=rel#Strings">
Strings
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<a class="eglink" href="/egs/java.lang/pkg.html?l=rel#System%20Properties">
System Properties
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