How to use the Fork/Join framework in Java function concurrency and multi-threading?

How to create parallel tasks using the Fork/Join framework in Java? Define task logic, calculate results or perform actions. Create a ForkJoinPool to manage parallel threads. Use the fork() method to submit tasks. Use the join() method to get task results.

Java Fork/Join Framework: Powerful Tools in Concurrency and Multithreading

The Fork/Join Framework is a Java concurrency library A powerful tool that parallelizes tasks using a divide-and-conquer strategy. It is based on a "task stealing" algorithm, where threads collaborate on tasks and steal tasks from a shared queue.

How to use the Fork/Join framework

1. Create a RecursiveTask or RecursiveAction class: Define the execution logic of the task, respectively for calculation results or performs an action.
2. Create a ForkJoinPool: Create a thread pool to manage concurrent threads.
3. Submit the task: Use the fork() method to submit the task to the thread pool.
4. Get the results: Use the join() method to get the execution results of the task.

Practical case: Fibonacci sequence

Use the Fork/Join framework to calculate the Fibonacci sequence:

import java.util.concurrent.ForkJoinPool;
import java.util.concurrent.ForkJoinTask;
import java.util.concurrent.RecursiveTask;

class FibonacciTask extends RecursiveTask<Long> {

    private final int n;

    public FibonacciTask(int n) {
        this.n = n;
    }

    @Override
    public Long compute() {
        if (n <= 1) {
            return (long) n;
        } else {
            FibonacciTask leftTask = new FibonacciTask(n - 1);
            FibonacciTask rightTask = new FibonacciTask(n - 2);
            leftTask.fork();
            rightTask.fork();
            return leftTask.join() + rightTask.join();
        }
    }
}

public class FibonacciForkJoin {

    public static void main(String[] args) {
        ForkJoinPool pool = new ForkJoinPool();
        int n = 40;
        FibonacciTask task = new FibonacciTask(n);
        Long result = pool.invoke(task);
        System.out.println("斐波那契数列第 " + n + " 项为：" + result);
    }
}

This example Created a FibonacciTask class that overrides the compute() method to calculate the Fibonacci sequence. It uses the fork() method to submit subtasks to the thread pool and the join() method to get the results. The FibonacciForkJoin class creates a ForkJoinPool and submits the FibonacciTask, then gets and prints the result.

The above is the detailed content of How to use the Fork/Join framework in Java function concurrency and multi-threading?. For more information, please follow other related articles on the PHP Chinese website!