soujava-threads-ForkJoinExample.java

package forkjoin;

import java.util.concurrent.RecursiveTask;

public class FibonacciTask extends RecursiveTask<Long> {

	/**
	 * 
	 */
	private static final long serialVersionUID = 8826018716775533826L;

	private final int THRESOULD = 5;
	
	private FibonacciProblem problem;
	
	private long result;
	
	public FibonacciTask(FibonacciProblem problem) {
		this.problem = problem;
	}

	protected Long compute() {
		if (problem.getN() < THRESOULD) {
			result = problem.solve();
		} else {
			FibonacciTask worker1 = new FibonacciTask(new FibonacciProblem(problem.getN() - 1));
			worker1.fork();
			
			FibonacciTask worker2 = new FibonacciTask(new FibonacciProblem(problem.getN() - 2));
			worker2.fork();
			
			result = worker2.join() + worker1.join();
		}
		return result;
	}

	public long getResult() {
		return result;
	}
}