java.lang.Object
java.util.concurrent.ForkJoinTask<V>
java.util.concurrent.RecursiveTask<V>
 All Implemented Interfaces:
Serializable
,Future<V>
public abstract class RecursiveTask<V> extends ForkJoinTask<V>
A recursive resultbearing
ForkJoinTask
.
For a classic example, here is a task computing Fibonacci numbers:
class Fibonacci extends RecursiveTask<Integer> {
final int n;
Fibonacci(int n) { this.n = n; }
protected Integer compute() {
if (n <= 1)
return n;
Fibonacci f1 = new Fibonacci(n  1);
f1.fork();
Fibonacci f2 = new Fibonacci(n  2);
return f2.compute() + f1.join();
}
}
However, besides being a dumb way to compute Fibonacci functions
(there is a simple fast linear algorithm that you'd use in
practice), this is likely to perform poorly because the smallest
subtasks are too small to be worthwhile splitting up. Instead, as
is the case for nearly all fork/join applications, you'd pick some
minimum granularity size (for example 10 here) for which you always
sequentially solve rather than subdividing. Since:
 1.7
 See Also:
 Serialized Form

Constructor Summary
Constructors Constructor Description RecursiveTask()

Method Summary
Methods declared in class java.util.concurrent.ForkJoinTask
adapt, adapt, adapt, cancel, compareAndSetForkJoinTaskTag, complete, completeExceptionally, fork, get, get, getException, getForkJoinTaskTag, getPool, getQueuedTaskCount, getRawResult, getSurplusQueuedTaskCount, helpQuiesce, inForkJoinPool, invoke, invokeAll, invokeAll, invokeAll, isCompletedAbnormally, isCompletedNormally, join, peekNextLocalTask, pollNextLocalTask, pollSubmission, pollTask, quietlyComplete, quietlyInvoke, quietlyJoin, reinitialize, setForkJoinTaskTag, setRawResult, tryUnfork
Methods declared in class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
Methods declared in interface java.util.concurrent.Future
isCancelled, isDone

Constructor Details

RecursiveTask
public RecursiveTask()


Method Details

compute
The main computation performed by this task. Returns:
 the result of the computation

exec
protected final boolean exec()Implements execution conventions for RecursiveTask. Specified by:
exec
in classForkJoinTask<V>
 Returns:
true
if this task is known to have completed normally
