/*
* Copyright 2016 the original author or authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License 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 org.springframework.statemachine.trigger;
import java.util.concurrent.ScheduledFuture;
import java.util.concurrent.TimeUnit;
import org.springframework.statemachine.support.CountTrigger;
import org.springframework.statemachine.support.LifecycleObjectSupport;
/**
* Implementation of a {@link Trigger} capable of firing on a
* static periods.
*
* @author Janne Valkealahti
*
* @param <S> the type of state
* @param <E> the type of event
*/
public class TimerTrigger<S, E> extends LifecycleObjectSupport implements Trigger<S, E> {
private final CompositeTriggerListener triggerListener = new CompositeTriggerListener();
private final long period;
private final int count;
private volatile ScheduledFuture<?> scheduled;
/**
* Instantiates a new timer trigger.
*
* @param period the period in milliseconds
*/
public TimerTrigger(long period) {
this(period, 0);
}
/**
* Instantiates a new timer trigger.
*
* @param period the period
* @param count the count
*/
public TimerTrigger(long period, int count) {
this.period = period;
this.count = count;
}
@Override
public boolean evaluate(TriggerContext<S, E> context) {
return false;
}
@Override
public void addTriggerListener(TriggerListener listener) {
triggerListener.register(listener);
}
@Override
public E getEvent() {
return null;
}
@Override
protected void doStart() {
if (count > 0) {
return;
}
schedule();
}
@Override
protected void doStop() {
cancel();
}
@Override
public void arm() {
if (scheduled != null) {
return;
}
schedule();
}
@Override
public void disarm() {
if (count > 0) {
cancel();
}
}
private void schedule() {
long initialDelay = count > 0 ? period : 0;
scheduled = getTaskScheduler().schedule(new Runnable() {
@Override
public void run() {
notifyTriggered();
}
}, new CountTrigger(count, period, initialDelay, TimeUnit.MILLISECONDS));
}
private void notifyTriggered() {
triggerListener.triggered();
}
private void cancel() {
if (scheduled != null) {
scheduled.cancel(true);
}
scheduled = null;
}
}