/*
* Copyright 2002-2012 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.integration.samples.poller;
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;
/**
* This is a dynamically changeable {@link Trigger}. It is based on the
* {@link PeriodicTrigger} implementations. However, the fields of this dynamic
* trigger are not final and the properties can be inspected and set via
* explicit getters and setters.
*
* @author Gunnar Hillert
*
*/
public class DynamicPeriodicTrigger implements Trigger {
private volatile long period;
private volatile TimeUnit timeUnit;
private volatile long initialDelay = 0;
private volatile boolean fixedRate = false;
/**
* Create a trigger with the given period in milliseconds. The underlying
* {@link TimeUnit} will be initialized to TimeUnit.MILLISECONDS.
*
* @param period Must not be negative
*/
public DynamicPeriodicTrigger(long period) {
this(period, TimeUnit.MILLISECONDS);
}
/**
* Create a trigger with the given 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 period Must not be negative
* @param timeUnit Must not be null
*
*/
public DynamicPeriodicTrigger(long period, TimeUnit timeUnit) {
Assert.isTrue(period >= 0, "period must not be negative");
Assert.notNull(timeUnit, "timeUnit must not be null");
this.timeUnit = timeUnit;
this.period = this.timeUnit.toMillis(period);
}
/**
* 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.
*/
public void setInitialDelay(long initialDelay) {
Assert.isTrue(initialDelay >= 0, "initialDelay must not be negative");
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.
*/
public void setFixedRate(boolean fixedRate) {
this.fixedRate = fixedRate;
}
/**
* Returns the time after which a task should run again.
*/
public Date nextExecutionTime(TriggerContext triggerContext) {
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);
}
public long getPeriod() {
return period;
}
/**
* Specify the period of the trigger. 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 period Must not be negative
*/
public void setPeriod(long period) {
Assert.isTrue(period >= 0, "period must not be negative");
this.period = this.timeUnit.toMillis(period);
}
public TimeUnit getTimeUnit() {
return timeUnit;
}
public void setTimeUnit(TimeUnit timeUnit) {
Assert.notNull(timeUnit, "timeUnit must not be null");
this.timeUnit = timeUnit;
}
public long getInitialDelay() {
return initialDelay;
}
public boolean isFixedRate() {
return fixedRate;
}
@Override
public boolean equals(Object obj) {
if (this == obj) {
return true;
}
if (!(obj instanceof DynamicPeriodicTrigger)) {
return false;
}
DynamicPeriodicTrigger other = (DynamicPeriodicTrigger) obj;
return this.fixedRate == other.fixedRate
&& this.initialDelay == other.initialDelay
&& this.period == other.period;
}
@Override
public int hashCode() {
return (this.fixedRate ? 14 : 41) +
(int) (38 * this.period) +
(int) (43 * this.initialDelay);
}
}