开发环境：
JDK7.0 + Eclipse3.6 + JUnit4
完整代码：
代码文件一：SortTask.java
package forktest;
import java.util.*;
import java.util.concurrent.RecursiveAction;
import java.util.concurrent.ForkJoinPool;
import java.util.concurrent.ForkJoinTask;
import junit.*;
public class SortTask extends RecursiveAction {
final long[] array;
final int hi;
final int lo;
private int THRESHOLD = 30;
//构造函数
public SortTask(long[] array)
{
this.array = array;
this.lo = 0;
this.hi = array.length - 1;
}
//构造函数
public SortTask(long[] array,int lo,int hi)
{
this.array = array;
this.lo = lo;
this.hi = hi;
}
//implement RecusiveTask must
protected void compute() {
if(hi - lo < THRESHOLD) {
sequentiallySort(array,lo,hi);
}
else
{
int pivot = partition(array,lo,hi);
System.out.println("\npivot = " + pivot + ", low = " + lo + ", high = " + hi);
System.out.println("array" + Arrays.toString(array));
//注意此处接口有变化，老版本是coInvake，已不支持该接口
invokeAll(new SortTask(array,lo,pivot-1),new SortTask(array,pivot+1,hi));
}
}
//任务分割
private int partition(long[] array,int lo,int hi){
long x = array[hi];
int i = lo - 1;
for (int j = lo; j < hi; j++) {
if (array[j] <= x) {
i++;
swap(array, i, j);
}
}
swap(array, i + 1, hi);
return i+1;
}
//执行排序
private void sequentiallySort(long[] array,int lo,int hi){
Arrays.sort(array,lo,hi+1);
}
//数值交换
private void swap(long[] array,int i,int j){
if(i !=j)
{
long tmp = array[i];
array[i] = array[j];
array[j] = tmp;
}
}
}
代码文件二：TestForkJoinSimple.java
package forktest;
import junit.*;
import org.junit.Before;
import org.junit.Test;
import static org.junit.Assert.*;
import java.util.*;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.RecursiveAction;
import java.util.concurrent.ForkJoinPool;
import java.util.concurrent.ForkJoinTask;
import forktest.SortTask;
public class TestForkJoinSimple {
private static final int NARRAY = 16; //For demo only
long[] array = new long[NARRAY];
Random rand = new Random();
@Before
public void setUp() {
for (int i = 0; i < array.length; i++) {
array[i] = rand.nextLong()%100; //For demo only
}
}
@Test
public void testSort() throws Exception {
ForkJoinTask sort = new SortTask(array);
ForkJoinPool fjpool = new ForkJoinPool();
fjpool.submit(sort);
fjpool.shutdown();
fjpool.awaitTermination(30, TimeUnit.SECONDS);
assertTrue(checkSorted(array));
}
boolean checkSorted(long[] a) {
for (int i = 0; i < a.length - 1; i++) {
if (a[i] > (a[i + 1])) {
return false;
}
}
return true;
}
}
运行结果：
pivot = 5, low = 0, high = 15
array[-88, -97, -25, -33, -25, 10, 62, 91, 43, 85, 35, 26, 57, 78, 66, 79]
pivot = 4, low = 0, high = 4
array[-88, -97, -25, -33, -25, 10, 62, 91, 43, 85, 35, 26, 57, 78, 66, 79]
pivot = 2, low = 0, high = 3
array[-88, -97, -33, -25, -25, 10, 62, 91, 43, 85, 35, 26, 57, 78, 66, 79]
pivot = 0, low = 0, high = 1
array[-97, -88, -33, -25, -25, 10, 62, 91, 43, 85, 35, 26, 57, 78, 66, 79]
pivot = 1, low = 1, high = 1
array[-97, -88, -33, -25, -25, 10, 62, 91, 43, 85, 35, 26, 57, 78, 66, 79]
pivot = 3, low = 3, high = 3
array[-97, -88, -33, -25, -25, 10, 62, 91, 43, 85, 35, 26, 57, 78, 66, 79]
pivot = 13, low = 6, high = 15
array[-97, -88, -33, -25, -25, 10, 62, 43, 35, 26, 57, 78, 66, 79, 91, 85]
pivot = 11, low = 6, high = 12
array[-97, -88, -33, -25, -25, 10, 62, 43, 35, 26, 57, 66, 78, 79, 91, 85]
pivot = 9, low = 6, high = 10
array[-97, -88, -33, -25, -25, 10, 43, 35, 26, 57, 62, 66, 78, 79, 91, 85]
pivot = 6, low = 6, high = 8
array[-97, -88, -33, -25, -25, 10, 26, 35, 43, 57, 62, 66, 78, 79, 91, 85]
pivot = 8, low = 7, high = 8
array[-97, -88, -33, -25, -25, 10, 26, 35, 43, 57, 62, 66, 78, 79, 91, 85]
pivot = 7, low = 7, high = 7
array[-97, -88, -33, -25, -25, 10, 26, 35, 43, 57, 62, 66, 78, 79, 91, 85]
pivot = 10, low = 10, high = 10
array[-97, -88, -33, -25, -25, 10, 26, 35, 43, 57, 62, 66, 78, 79, 91, 85]
pivot = 12, low = 12, high = 12
array[-97, -88, -33, -25, -25, 10, 26, 35, 43, 57, 62, 66, 78, 79, 91, 85]
pivot = 14, low = 14, high = 15
array[-97, -88, -33, -25, -25, 10, 26, 35, 43, 57, 62, 66, 78, 79, 85, 91]
pivot = 15, low = 15, high = 15
array[-97, -88, -33, -25, -25, 10, 26, 35, 43, 57, 62, 66, 78, 79, 85, 91]
注意事项：
JDK版本必须是7.0及以上版本，否则不支持；JUnit必须是4.0及以上版本，否则不支持。
