/*
* Copyright 2015-2016 Amazon.com, Inc. or its affiliates. All Rights Reserved.
*
* Licensed under the Apache License, Version 2.0 (the "License").
* You may not use this file except in compliance with the License.
* A copy of the License is located at
*
* http://aws.amazon.com/apache2.0
*
* or in the "license" file accompanying this file. This file is distributed
* on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either
* express or implied. See the License for the specific language governing
* permissions and limitations under the License.
*/
package com.amazonaws.eclipse.elasticbeanstalk.util;
import java.util.concurrent.TimeUnit;
/**
* Class to poll until a given {@link Event} has occurred at a specified interval and up to a max
* number of iterations
*/
public class PollForEvent {
/**
* Interface to represent a certain event and whether it has occurred or not.
*/
public interface Event {
/**
* @return True if event has occurred, false otherwise
*/
public boolean hasEventOccurred();
}
/**
* Represents an interval of time with units specified
*/
public static class Interval {
private final long millis;
public Interval(long value, TimeUnit unit) {
millis = unit.toMillis(value);
}
private long getMillis() {
return millis;
}
}
private final Interval interval;
private final long maxNumberOfIntervalsToPollFor;
/**
* @param interval
* {@link Interval} of time to wait between checking the event status
* @param maxNumberOfIntervalsToPollFor
* Max intervals to poll for before giving up
*/
public PollForEvent(Interval interval, int maxNumberOfIntervalsToPollFor) {
this.interval = interval;
this.maxNumberOfIntervalsToPollFor = maxNumberOfIntervalsToPollFor;
}
public void poll(Event event) {
int currentPollInterval = 0;
while (!event.hasEventOccurred() && !hasReachedMaxPollInterval(currentPollInterval)) {
try {
Thread.sleep(interval.getMillis());
} catch (InterruptedException e) {
Thread.currentThread().interrupt();
}
currentPollInterval++;
}
}
public boolean hasReachedMaxPollInterval(int currentPollInterval) {
return currentPollInterval >= maxNumberOfIntervalsToPollFor;
}
}