Question

我试图从Guava中获取FutureCallbacks，因为我想在我的java api中使用它来获得cloudflare。

测试类：

import com.google.common.util.concurrent.*;

import javax.annotation.Nullable;
import java.util.concurrent.Callable;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

public class Test {

    @org.junit.Test

    public static void apiUsersCode( ) {
        apiMethodThatReturnsCloudflareInfos( new FutureCallback<String>() {
            @Override
            public void onSuccess( @Nullable String result ) {
                System.out.println( "WORKING" );
            }

            @Override
            public void onFailure( Throwable t ) {
                System.out.println( t );
            }
        } );
    }

    public static void apiMethodThatReturnsCloudflareInfos( FutureCallback<String> usersFutureCallback ) {
        Callable<String> solution = ( ) -> {
            Thread.sleep( 1000L ); // simulate slowness of next line
            return "http output"; // this is this other method that sends a http request
        };

        // runs callable async, when done: execute usersFutureCallback
        ExecutorService executor = Executors.newFixedThreadPool( 10 );
        ListeningExecutorService service = MoreExecutors.listeningDecorator( executor );
        ListenableFuture<String> listenableFuture = service.submit( solution );
        Futures.addCallback( listenableFuture, usersFutureCallback, service );
    }
}

当有人使用此api简化时：

他调用一个方法并传递一个FutureCallback对象（usersFutureCallback）
此方法运行另一种方法，其输出以可调用的
完成

由用户执行的示例Api方法

apiMethodThatReturnsCloudflareInfos( new FutureCallback<String>() {
    @Override
    public void onSuccess( @Nullable String cloudflareOutput ) {
        System.out.println( "WORKING" );
    }

    @Override
    public void onFailure( Throwable t ) {
        System.out.println( t );
    }
} );

示例api方法简化

public static void apiMethodThatReturnsCloudflareInfos( FutureCallback<String> usersFutureCallback ) {
    Callable<String> solution = ( ) -> {
        Thread.sleep( 1000L ); // simulate slowness of next line
        return "http output"; // this is this other method that sends a http request
    };

    // runs callable async, when done: execute usersFutureCallback
    ExecutorService executor = Executors.newFixedThreadPool( 10 );
    ListeningExecutorService service = MoreExecutors.listeningDecorator( executor );
    ListenableFuture<String> listenableFuture = service.submit( solution );
    Futures.addCallback( listenableFuture, usersFutureCallback, service );
}

＆＃34;工作＆＃34;仅在更改和添加此行以在可调用完成后添加侦听器时打印。但这不是原因的解决方案。

public static void apiMethodThatReturnsCloudflareInfos( FutureCallback<String> usersFutureCallback ) {
    Callable<String> solution = ( ) -> {
        Thread.sleep( 1000L ); // simulate slowness of next line
        return "http output"; // this is this other method that sends a http request
    };

    // runs callable async, when done: execute usersFutureCallback
    ExecutorService executor = Executors.newFixedThreadPool( 10 );
    ListeningExecutorService service = MoreExecutors.listeningDecorator( executor );
    ListenableFuture<String> listenableFuture = service.submit( solution );

    // i don't want that
    try {
        Thread.sleep( 10001L );
    } catch ( InterruptedException e ) {
        e.printStackTrace();
    }

    Futures.addCallback( listenableFuture, usersFutureCallback, service );
}

我做错了什么？

Answer 1

问题在于您如何测试该方法。你基本上创建一个运行你的Callable<String> solution的新线程，但没有什么会等待该线程完成。一旦您的测试方法完成，您的测试套件将终止并使用正在运行的线程solution。

在现实生活中，您的应用程序的使用寿命超过solution，您将无法遇到此问题。

要解决此问题，您必须更新测试用例，以免过早终止。您可以通过更新apiUsersCode()来设置onSuccess和onFailure中的某个值，并在调用apiMethodThatReturnsCloudflareInfos后等待。{/ p>

Answer 2

<强>解决！

问题是测试套装JUnit。它在main（String [] args）方法中测试时有效。

......一切都是正确的只有应该帮助我进行测试的错误：D

Query lastmess = FirebaseDatabase.getInstance().getReference("Messages").child(my_Id).child(sendUID);
lastmess.orderByKey().limitToLast(1).addListenerForSingleValueEvent(new ValueEventListener() {
    @Override
    public void onDataChange(DataSnapshot dataa) {
        for (DataSnapshot snap : dataa.getChildren()) {
            MessModel messages = snap.getValue(MessModel.class);
            String mes = messages.getMessage(); //here I can get the last message
            messages.setMessage("updated Message"); //here is the problem , why it doesn't work ?
        }
    }

    @Override
        public void onCancelled(DatabaseError databaseError) {
    }
});

FutureCallback从未执行过

2 个答案: