/*
* 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.support;
import java.util.Date;
import java.util.concurrent.TimeUnit;
import org.springframework.scheduling.Trigger;
import org.springframework.scheduling.TriggerContext;
import org.springframework.scheduling.support.PeriodicTrigger;
import org.springframework.util.Assert;
/**
* Enhanced implementation following same logic from {@link PeriodicTrigger}
* except also adding a counter how many times a trigger can fire. If given
* count is either zero on a negative value, counter functionality is disabled.
*
* @author Janne Valkealahti
* @see PeriodicTrigger
*/
public class CountTrigger implements Trigger {
private final int count;
private final long period;
private final TimeUnit timeUnit;
private volatile long initialDelay = 0;
private volatile boolean fixedRate = false;
private volatile int counter = 0;
/**
* Create a trigger with the given period in milliseconds and firing
* exactly one time.
*
* @param period the period
*/
public CountTrigger(long period) {
this(1, period, null);
}
/**
* Create a trigger with the given count, period and time unit. The time unit will
* apply not only to the period but also to any 'initialDelay' value, if
* configured on this Trigger later via {@link #setInitialDelay(long)}.
*
* @param count the count
* @param period the period
* @param timeUnit the time unit
*/
public CountTrigger(int count, long period, TimeUnit timeUnit) {
this(count, period, 0, timeUnit);
}
/**
* Create a trigger with the given count, period and time unit. The time unit will
* apply not only to the period but also to any 'initialDelay' value, if
* configured on this Trigger later via {@link #setInitialDelay(long)}.
*
* @param count the count
* @param period the period
* @param timeUnit the time unit
* @param initialDelay the initial delay
*/
public CountTrigger(int count, long period, long initialDelay, TimeUnit timeUnit) {
Assert.isTrue(period >= 0, "period must not be negative");
Assert.isTrue(count >= 0, "count must not be negative");
this.timeUnit = (timeUnit != null ? timeUnit : TimeUnit.MILLISECONDS);
this.period = this.timeUnit.toMillis(period);
this.count = count;
setInitialDelay(initialDelay);
}
/**
* Specify the delay for the initial execution. It will be evaluated in
* terms of this trigger's {@link TimeUnit}. If no time unit was explicitly
* provided upon instantiation, the default is milliseconds.
*
* @param initialDelay the new initial delay
*/
public void setInitialDelay(long initialDelay) {
this.initialDelay = this.timeUnit.toMillis(initialDelay);
}
/**
* Specify whether the periodic interval should be measured between the
* scheduled start times rather than between actual completion times.
* The latter, "fixed delay" behavior, is the default.
*
* @param fixedRate the new fixed rate
*/
public void setFixedRate(boolean fixedRate) {
this.fixedRate = fixedRate;
}
@Override
public Date nextExecutionTime(TriggerContext triggerContext) {
if (count > 0) {
if (++counter > count) {
return null;
}
}
if (triggerContext.lastScheduledExecutionTime() == null) {
return new Date(System.currentTimeMillis() + this.initialDelay);
}
else if (this.fixedRate) {
return new Date(triggerContext.lastScheduledExecutionTime().getTime() + this.period);
}
return new Date(triggerContext.lastCompletionTime().getTime() + this.period);
}
@Override
public int hashCode() {
final int prime = 31;
int result = 1;
result = prime * result + count;
result = prime * result + (fixedRate ? 1231 : 1237);
result = prime * result + (int) (initialDelay ^ (initialDelay >>> 32));
result = prime * result + (int) (period ^ (period >>> 32));
return result;
}
@Override
public boolean equals(Object obj) {
if (this == obj)
return true;
if (obj == null)
return false;
if (getClass() != obj.getClass())
return false;
CountTrigger other = (CountTrigger) obj;
if (count != other.count)
return false;
if (fixedRate != other.fixedRate)
return false;
if (initialDelay != other.initialDelay)
return false;
if (period != other.period)
return false;
return true;
}
}