【发布时间】：2020-05-13 10:56:13
【问题描述】：
我正在使用 Eclipse 2020-03 (4.15.0) 和 Sonarlint for Eclipse 5.1.0.17086，我在以下代码中收到了 IMO 误报 S1854 警告（摘自“Java 8 In Action”一书）。使用 Java OpenJDK 13.0.2。这不是什么大事，因为我只是在学习 Java 8 技术。我只是想了解为什么这些行被标记...
package nl.paul.forkjoin;
import java.util.concurrent.RecursiveTask;
public class ForkJoinSumCalculator extends RecursiveTask<Long> {
private static final long serialVersionUID = 1L;
private final long[] numbers;
private final int start;
private final int end;
public static final long THRESHOLD = 10_000;
public ForkJoinSumCalculator(long[] numbers) {
this(numbers, 0, numbers.length);
}
private ForkJoinSumCalculator(long[] numbers, int start, int end) {
this.numbers = numbers;
this.start = start;
this.end = end;
}
@Override
protected Long compute() {
int length = end - start; //SonarLint S1854 warning
if (length <= THRESHOLD) {
return computeSequentially();
}
ForkJoinSumCalculator leftTask = new ForkJoinSumCalculator(numbers, start, start + length / 2); //SonarLint S1854 warning
ForkJoinSumCalculator rightTask = new ForkJoinSumCalculator(numbers, start + length / 2, end); //SonarLint S1854 warning
leftTask.fork();
return leftTask.join() + rightTask.compute();
}
private long computeSequentially() {
long sum = 0;
for (int i = start; i < end; i++) {
sum += numbers[i];
}
return sum;
}
}
我在这里错过了什么吗？ “length”、“leftTask”和“rightTask”都在代码中多次使用...
上面的类是用下面的类测试的：
package nl.paul.forkjoin;
import java.util.concurrent.ForkJoinPool;
import java.util.concurrent.ForkJoinTask;
import java.util.stream.LongStream;
public class ForkJoinTest {
public static void main(String[] args) {
System.out.println(new ForkJoinTest().doIt(10_000_000));
}
private long doIt(long n) {
long[] numbers = LongStream.rangeClosed(0, n).toArray();
long start = System.currentTimeMillis();
ForkJoinTask<Long> task = new ForkJoinSumCalculator(numbers);
long result = new ForkJoinPool().invoke(task);
long finish = System.currentTimeMillis();
System.out.println("Processing took " + (finish - start) + " msec.");
return result;
}
}
【问题讨论】：
-
什么是
end、start和THRESHOLD？请提供minimal reproducible example。 -
编辑添加更多代码信息。
标签： java eclipse sonarlint-eclipse