如何将 Callable 与 void 返回类型一起使用? [英] How to use Callable with void return type?

问题描述

我正在开发一个项目，其中有多个接口和两个需要实现这两个接口的实现类.

I am working on a project in which I have multiple interface and two Implementations classes which needs to implement these two interfaces.

假设我的第一个界面是 -

Suppose my first Interface is -

public Interface interfaceA {
    public void abc() throws Exception;
}

它的实现是 -

public class TestA implements interfaceA {

// abc method
}

我是这样称呼它的 -

I am calling it like this -

TestA testA = new TestA();
testA.abc();

现在我的第二个界面是 -

Now my second interface is -

public Interface interfaceB {
    public void xyz() throws Exception;
}

它的实现是 -

public class TestB implements interfaceB {

// xyz method   
}

我是这样称呼它的 -

I am calling it like this -

TestB testB = new TestB();
testB.xyz();

问题陈述:-

现在我的问题是 - 有什么办法可以并行执行这两个实现类吗?我不想按顺序运行它.

Now my question is - Is there any way, I can execute these two implementation classes in parallel? I don't want to run it in sequential.

意思是，我想并行运行 TestA 和 TestB 实现?可以这样做吗?

Meaning, I want to run TestA and TestB implementation in parallel? Is this possible to do?

我想在这里使用 Callable 但不确定如何在这里使用带有 void 返回类型的 Callable -

I was thinking to use Callable here but not sure how to use Callable with void return type here -

我们以TestB类为例:

Let's use TestB class as an example:

public interface interfaceB {
    public void xyz() throws Exception;
}

public class TestB implements interfaceB, Callable<?>{

    @Override
    public void xyz() throws Exception
    {
        //do something

    }

    @Override
    public void call() throws Exception
    {
        xyz();
    }
}

上面的代码给出了编译错误..

Above code gives compilation error..

更新:-

看起来很多人都建议使用 Runnable 而不是 callable.但不确定如何在这里使用 Runnable 以便我可以并行执行 TestA 和 TestB.

It looks like lot of people are suggesting to use Runnable instead of callable. But not sure how do I use Runnable here so that I can execute TestA and TestB in parallel.

推荐答案

您可以使用 java.lang.Thread 进行并行执行.但是，在大多数情况下，使用 java.util.concurrent.ExecutorService 更容易.后者提供了一个方法来提交一个Callable并返回一个Future以便稍后获取结果(或等待完成).

You can use java.lang.Thread for parallel execution. However, in most cases it's easier to use an java.util.concurrent.ExecutorService. The latter provides a method to submit a Callable and returns a Future to get the result later (or wait for completion).

如果 testA.abc() 和 testB.xyz() 应该并行执行，则使用 ExecutorService 来执行前者在一个单独的线程中，而后者在原始线程中执行.然后等待前者完成同步.

If testA.abc() and testB.xyz() should be executed in parallel, you use the ExecutorService to execute the former in a separate thread whereas the latter is executed in the original thread. Then you wait for the completion of the former for synchronization.

ExecutorService executor = ... // e.g. Executors.newFixedThreadPool(4);

Future<Void> future = executor.submit(new Callable<Void>() {
    public Void call() throws Exception {
        testA.abc();
        return null;
    }
});
testB.xyz();
future.get(); // wait for completion of testA.abc()

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