Java Reference
In-Depth Information
startAllCoreThreads()
method, and then you wait until all the
Runnable
ob-
jects are done executing by calling the
shutdown()
method, followed by the
awaitTermination()
method:
private void start() throws InterruptedException {
BlockingQueue<Runnable> queue = new
LinkedBlockingQueue<>();
for (int i =0;i < 10;i++) {
final int localI = i;
queue.add((Runnable) () -> {
doExpensiveOperation(localI);
});
}
ThreadPoolExecutor executor = new
ThreadPoolExecutor(10,10,1000,
TimeUnit.MILLISECONDS, queue);
executor.prestartAllCoreThreads();
executor.shutdown();
executor.awaitTermination(100000,TimeUnit.SECONDS);
System.out.println("Look ma! all operations were
completed");
}
How It Works
A
ThreadPoolExecutor
consists of two components: the
Queue
of tasks to be
executed, and the
Executor
, which tells how to execute the tasks. The
Queue
is
filled with
Runnable
objects, on which the method
run()
contains the code to be
executed.
The
Queue
used by a
ThreadPoolExecutor
is an implementer of the
BlockingQueue
interface. The
BlockingQueue
interface denotes a queue in
which the consumers of the queue will wait (be suspended) if there are no elements
within the
Queue
. This is necessary for the
ThreadPoolExecutor
to work effi-
ciently.
