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prameshbhattarai/SubmitTask.java

Last active October 30, 2019 08:42
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Executor Service: Submit method
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SubmitTask.java
public class SubmitTask {
private static final int DEFAULT_THREAD_COUNT = 4; // default number of threads
private final ThreadPoolExecutor executorService;
public SubmitTask() {
this.executorService = (ThreadPoolExecutor) Executors.newFixedThreadPool(DEFAULT_THREAD_COUNT);
}
// if we only submit task to executor service then our thread pool will not closed
// even after completion of processing callable threads.
public <T> Future<T> submitTask(Callable<T> callable) {
return executorService.submit(callable);
}
public void invokeAll(List<Callable<Long>> callableList) {
try {
// execute all callable and store the results to future
List<Future<Long>> futures = executorService.invokeAll(callableList);
for(Future<Long> future : futures) {
System.out.println("Is Done " + future.isDone());
Long processedData = future.get();
System.out.println("Thread Id " + processedData);
}
System.out.println("Force stop executing task");
executorService.shutdownNow();
} catch (InterruptedException | ExecutionException e) {
e.printStackTrace();
}
}
public static void main(String... args) {
List<Callable<Long>> callableList = new ArrayList<>();
Callable<Long> callable = () -> {
final long startTime = System.nanoTime();
System.out.println("Start to Submit: Thread Name " + Thread.currentThread().getId() + " name " + Thread.currentThread().getName());
try {
Thread.sleep(randomMilliSecond());
final long endTime = System.nanoTime();
System.out.println("Complete processing, Thread Id: " + Thread.currentThread().getId() + ", Thread Name: " + Thread.currentThread().getName());
System.out.println("Time to process, Thread Id: " + Thread.currentThread().getId() + ", Thread Name: " + Thread.currentThread().getName() + ", time : " + (endTime - startTime));
} catch (InterruptedException e) {
e.printStackTrace();
}
return Thread.currentThread().getId();
};
callableList.add(callable);
callableList.add(callable);
callableList.add(callable);
callableList.add(callable);
callableList.add(callable);
SubmitTask submit = new SubmitTask();
List<Future<Long>> futures = callableList.stream().map(submit::submitTask).collect(Collectors.toList());
// for(Future<Long> future : futures) {
// System.out.println("Is Done: " + future.isDone());
// }
submit.invokeAll(callableList);
}
private static long randomMilliSecond(){
return (long)(Math.random() * 10) * 1000;
}
}
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