org.springframework.scheduling.timer.TimerTaskExecutor Maven / Gradle / Ivy
/*
* Copyright 2002-2006 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.scheduling.timer;
import java.util.Timer;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.springframework.beans.factory.DisposableBean;
import org.springframework.beans.factory.InitializingBean;
import org.springframework.scheduling.SchedulingTaskExecutor;
import org.springframework.util.Assert;
/**
* {@link org.springframework.core.task.TaskExecutor} implementation that uses a
* single {@link Timer} for executing all tasks, effectively resulting in
* serialized asynchronous execution on a single thread.
*
* @author Juergen Hoeller
* @since 2.0
* @see java.util.Timer
*/
public class TimerTaskExecutor implements SchedulingTaskExecutor, InitializingBean, DisposableBean {
/**
* The shared {@link Log} instance.
*/
protected final Log logger = LogFactory.getLog(getClass());
private Timer timer;
private int delay = 0;
private boolean usingAnInternalTimer = false;
/**
* Create a new TimerTaskExecutor that needs to be further
* configured and initialized.
* @see #setTimer
* @see #afterPropertiesSet
*/
public TimerTaskExecutor() {
}
/**
* Create a new TimerTaskExecutor for the given {@link Timer}.
* @param timer the {@link Timer} to wrap
* @throws IllegalArgumentException if the supplied {@link Timer} is null
*/
public TimerTaskExecutor(Timer timer) {
Assert.notNull(timer, "Timer must not be null");
this.timer = timer;
}
/**
* Set the {@link Timer} to use for this {@link TimerTaskExecutor},
* for example a shared {@link Timer} instance defined by a
* {@link TimerFactoryBean}.
* If not specified, a default {@link Timer} instance will be used.
* @param timer the {@link Timer} to use for this {@link TimerTaskExecutor} (may be null)
* @see TimerFactoryBean
*/
public void setTimer(Timer timer) {
this.timer = timer;
}
/**
* Set the delay to use for scheduling tasks passed into the
* execute method. Default is 0.
* @param delay the delay in milliseconds before the task is to be executed
*/
public void setDelay(int delay) {
this.delay = delay;
}
public void afterPropertiesSet() {
if (this.timer == null) {
logger.info("Initializing Timer");
this.timer = createTimer();
this.usingAnInternalTimer = true;
}
}
/**
* Create a new {@link Timer} instance. Called by afterPropertiesSet
* if no {@link Timer} has been specified explicitly.
*
Default implementation creates a plain daemon {@link Timer}.
*
If overridden, subclasses must take care to ensure that a non-null
* {@link Timer} is returned from the execution of this method.
* @return a new {@link Timer} instance
* @see #afterPropertiesSet
* @see java.util.Timer#Timer(boolean)
*/
protected Timer createTimer() {
return new Timer(true);
}
/**
* Schedules the given {@link Runnable} on this executor's {@link Timer} instance,
* wrapping it in a {@link DelegatingTimerTask}.
* @param task the task to be executed
* @throws IllegalArgumentException if the supplied {@link Runnable task} is null,
* or if the {@link Timer} encapsulated by this instance has not been set, or
* if the {@link #setDelay(int) configured delay} is negative.
*/
public void execute(Runnable task) {
Assert.notNull(this.timer, "timer is required");
this.timer.schedule(new DelegatingTimerTask(task), this.delay);
}
/**
* This task executor prefers short-lived work units.
*/
public boolean prefersShortLivedTasks() {
return true;
}
/**
* Cancel the {@link Timer} on bean factory shutdown, stopping all scheduled tasks.
* @see java.util.Timer#cancel()
*/
public void destroy() {
if (this.usingAnInternalTimer) {
logger.info("Cancelling Timer");
this.timer.cancel();
}
}
}