10 |
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* Recursive result-bearing ForkJoinTasks. |
11 |
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* <p> For a classic example, here is a task computing Fibonacci numbers: |
12 |
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* |
13 |
< |
* <pre> |
14 |
< |
* class Fibonacci extends RecursiveTask<Integer> { |
13 |
> |
* <pre> {@code |
14 |
> |
* class Fibonacci extends RecursiveTask<Integer> { |
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* final int n; |
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* Fibonacci(int n) { this.n = n; } |
17 |
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* Integer compute() { |
18 |
< |
* if (n <= 1) |
18 |
> |
* if (n <= 1) |
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* return n; |
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* Fibonacci f1 = new Fibonacci(n - 1); |
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* f1.fork(); |
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* Fibonacci f2 = new Fibonacci(n - 2); |
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* return f2.compute() + f1.join(); |
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* } |
25 |
< |
* } |
26 |
< |
* </pre> |
25 |
> |
* }}</pre> |
26 |
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* |
27 |
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* However, besides being a dumb way to compute Fibonacci functions |
28 |
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* (there is a simple fast linear algorithm that you'd use in |
32 |
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* minimum granularity size (for example 10 here) for which you always |
33 |
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* sequentially solve rather than subdividing. |
34 |
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* |
35 |
+ |
* @since 1.7 |
36 |
+ |
* @author Doug Lea |
37 |
|
*/ |
38 |
|
public abstract class RecursiveTask<V> extends ForkJoinTask<V> { |
39 |
|
|
40 |
|
/** |
40 |
– |
* Empty constructor for use by subclasses. |
41 |
– |
*/ |
42 |
– |
protected RecursiveTask() { |
43 |
– |
} |
44 |
– |
|
45 |
– |
/** |
41 |
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* The result returned by compute method. |
42 |
|
*/ |
43 |
|
V result; |