RunnableFuture<V> Interface
This interface extends both Future<V> and Runnable interfaces.
Successful execution of the run method causes completion of the Future and allows access to its results.
FutureTask<V> class
This class implements RunnableFuture . It wraps either a Callable<T> or Runnable .
Examples
Following example uses FutureTask with java.lang.Thread .
package com.logicbig.example;
import java.util.concurrent.Callable;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.FutureTask;
public class FutureTaskExample {
public static void main(String[] args) throws ExecutionException, InterruptedException {
FutureTask<String> futureTask = new FutureTask<>(new Callable<String>() {
@Override
public String call() {
try {
//simulating long running task
Thread.sleep(1000);
} catch (InterruptedException e) {
e.printStackTrace();
}
System.out.println("task finished");
return "The result";
}
});
new Thread(futureTask).start();
System.out.println("Thread started");
String s = futureTask.get();
System.out.println(s);
}
}
Thread started task finished The result
Following examples use FutureTask with ExecutorService.
package com.logicbig.example;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.FutureTask;
public class FutureTaskWithExecutorExample {
public static void main(String[] args) throws ExecutionException, InterruptedException {
FutureTask<String> futureTask = new FutureTask<>(new Runnable() {
@Override
public void run() {
try {
//simulating long running task
Thread.sleep(1000);
} catch (InterruptedException e) {
e.printStackTrace();
}
System.out.println("task finished");
}
}, "The result");
ExecutorService es = Executors.newSingleThreadExecutor();
es.execute(futureTask);
String s = futureTask.get();
System.out.println(s);
es.shutdown();
}
}
task finished The result
package com.logicbig.example;
import java.util.concurrent.*;
public class FutureTaskWithExecutorExample2 {
public static void main(String[] args) throws ExecutionException, InterruptedException {
FutureTask<String> futureTask = new FutureTask<>(new Callable<String>() {
@Override
public String call() throws Exception {
//simulating long running task
Thread.sleep(1000);
System.out.println("returning");
return "The result";
}
}
);
ExecutorService es = Executors.newSingleThreadExecutor();
es.execute(futureTask);
String s = futureTask.get();
System.out.println(s);
es.shutdown();
}
}
returning The result
Example ProjectDependencies and Technologies Used:
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