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ForJoinTest.java
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74 lines (60 loc) · 1.51 KB
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package Chapter14Thread.forkJoin;
import java.util.concurrent.ForkJoinPool;
import java.util.concurrent.RecursiveTask;
public class ForJoinTest {
public static void main(String[] args) {
final int SIZE=1000;
boolean flag;
double[] numbers=new double[SIZE];
for(int i=0;i<SIZE;i++){
numbers[i]=Math.random();
}
Counter counter=new Counter(numbers, 0, numbers.length, new Filter(){
public boolean accept(double d) {
// TODO Auto-generated method stub
return d>0.8;
}
});
ForkJoinPool pool=new ForkJoinPool();
//执行
pool.invoke(counter);
//join（）返回结果
System.out.println("一共有"+counter.join()+"满足条件");
}
}
interface Filter{
boolean accept(double d);
}
//将会产生一个T类型的结果
class Counter extends RecursiveTask<Integer>{
public static final int THRESHOLD=100;
private double[] values;
private int from;
private int to;
private Filter filter;
public Counter(double[] values,int from ,int to,Filter filter){
this.values=values;
this.from=from;
this.to=to;
this.filter=filter;
}
@Override
protected Integer compute() {
if(to-from<THRESHOLD){
int count=0;
//如果在from和to之间的数满足filter.accept(i)，count++
for(int i=from;i<to;i++){
if(filter.accept(values[i])){
count++;
}
}
return count;
}else{
int mid=(from+to)/2;
Counter first=new Counter(values,from,mid,filter);
Counter second=new Counter(values,mid,to,filter);
this.invokeAll(first,second);
return first.join()+second.join();
}
}
}