Retry Strategy Implementation

Hi, this small portion of code is to be used when ever you need to perform a task that may fail and in which event you should retry a predefined amount of times.

I won't be explaining the code in detail but if you have questions please to comment :D.

RetriableTask Class:

public class RetriableTask<V> implements Callable<V> {

    private static final int DEFAULT_RETRY_ATTEMPTS = 3;

    private static final int DEFAULT_TIME_BETWEEN_RETRIES = 1000;

    private Callable<V> task;

    private int retryAttempts;

    private int timeBetweenRetries;

    private int retryCount;

    public RetriableTask(Callable<V> task) {

        this(task, DEFAULT_RETRY_ATTEMPTS, DEFAULT_TIME_BETWEEN_RETRIES);

    }

    public RetriableTask(Callable<V> task, int retryAttempts, int timeBetweenRetries) {

        this.task = task;

        this.retryAttempts = retryAttempts;

        this.timeBetweenRetries = timeBetweenRetries;

        this.retryCount = retryAttempts;

    }

    @Override

    public V call() throws Exception {

        while (true) {

            try {

                return task.call();

            } catch (InterruptedException e) {

                throw e;

            } catch (CancellationException e) {

                throw e;

            } catch (Exception e) {

                retryCount--;

                if (retryCount == 0) {

                    throw new RetryException(retryAttempts + " attempts to retry failed at " + timeBetweenRetries

                            + "ms interval", e);

                }

                Thread.sleep(timeBetweenRetries);

            }

        }

    }

}

How to use the class above:

Put this code in a method of your choosing. Of course this can be perfected and used in such way as to change what ever task you want to perform in runtime.

Callable<T> task = new Callable<T>() {

@Override

public T call() throws Exception {

    return // WHAT EVER YOU NEED TO ACTUALLY DO;

        }

};

       

       

String response = "";

try {

    response = new RetriableTask<String>(task).call();

} catch (RetryException e) {

    // THIS WILL BE CATCH WHEN:

    // The call to the task fails and all the retries were exausted

    // So do what ever you need to do when your operation fails:

    // HERE

} catch (Exception e) {

    // If you reach this point something else

    // besides the actuall retry failed

    throw new RuntimeException(e);

}