Threads - Beginning Java 8 Language Features - page 261

Thread.sleep(sleepTime * 1000);
totalSleepTime = totalSleepTime + sleepTime;
}
catch(InterruptedException e) {
System.out.println("Task #" + this.taskId +
" has been interupted.");
throw e;
}
}
return totalSleepTime;
}
}
The call() method of the task returns the sum of all its sleeping periods. Listing 6-50 illustrates the use of the
Callable task.
Listing 6-50. A Class to Demonstrate How to Use a Callable Task with an Executor
// CallableTaskTest.java
package com.jdojo.threads;
import java.util.concurrent.Executors;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Future;
import java.util.concurrent.ExecutionException;
public class CallableTaskTest {
public static void main(String[] args) {
// Get an executor with three threads in its thread pool
ExecutorService exec = Executors.newFixedThreadPool(3);
// Create the callable task with loop counter as 3
CallableTask task = new CallableTask(1, 3);
// Submit the callable task to executor
Future<Integer> submittedTask = exec.submit(task);
try {
Integer result = submittedTask.get();
System.out.println("Task's total sleep time: " + result + " seconds");
}
catch (ExecutionException e) {
System.out.println("Error in executing the task.");
}
catch (InterruptedException e) {
System.out.println("Task execution has been interrupted.");
}
// Let's shutdown the executor
exec.shutdown();
}
}