Java通过Fork/Join优化并行计算

时间:2022-04-12 10:01:39

本文实例为大家分享了Java通过Fork/Join优化并行计算的具体代码,供大家参考,具体内容如下

Java代码:

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package Threads;
 
import java.util.concurrent.ForkJoinPool;
import java.util.concurrent.RecursiveAction;
 
/**
 * Created by Frank
 */
public class RecursiveActionDemo extends RecursiveAction {
 
  static int[] raw = {19, 3, 0, -1, 57, 24, 65, Integer.MAX_VALUE, 42, 0, 3, 5};
  static int[] sorted = null;
  int[] source;
  int[] dest;
  int length;
  int start;
  final static int THRESHOLD = 4;
 
  public static void main(String[] args) {
    sorted = new int[raw.length];
 
    ForkJoinPool pool = new ForkJoinPool();
    pool.invoke(new RecursiveActionDemo(raw, 0, raw.length, sorted));
 
    System.out.println('[');
    for (int i : sorted) {
      System.out.println(i + ",");
    }
    System.out.println(']');
  }
 
  public RecursiveActionDemo(int[] source, int start, int length, int[] dest) {
    this.source = source;
    this.dest = dest;
    this.length = length;
    this.start = start;
  }
 
  @Override
  protected void compute() {
    System.out.println("ForkJoinDemo.compute()");
    if (length < THRESHOLD) {  // 直接计算
      for (int i = start; i < start + length; i++) {
        dest[i] = source[i] * source[i];
      }
    } else { // 分而治之
      int split = length / 2;
      /**
       * invokeAll反复调用fork和join直到完成。
       */
      invokeAll(new RecursiveActionDemo(source, start, split, dest), new RecursiveActionDemo(source, start + split, length - split, dest));
    }
  }
}

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