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/*
* ConcurrentScheduler.java February 2007
*
* Copyright (C) 2007, Niall Gallagher <niallg@users.sf.net>
*
* 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.simpleframework.common.thread;
import java.util.concurrent.TimeUnit;
/**
* The <code>ConcurrentScheduler</code> object is used to schedule tasks
* for execution. This queues the task for the requested period of
* time before it is executed. It ensures that the delay is adhered
* to such that tasks can be timed for execution in an accurate way.
*
* @author Niall Gallagher
*/
public class ConcurrentScheduler implements Scheduler {
/**
* This is the scheduler queue used to enque tasks to execute.
*/
private final SchedulerQueue queue;
/**
* Constructor for the <code>ConcurrentScheduler</code> object.
* This will create a scheduler with a fixed number of threads to
* use before execution. Depending on the types of task that are
* to be executed this should be increased for accuracy.
*
* @param type this is the type of the worker threads
*/
public ConcurrentScheduler(Class type) {
this(type, 10);
}
/**
* Constructor for the <code>ConcurrentScheduler</code> object.
* This will create a scheduler with a fixed number of threads to
* use before execution. Depending on the types of task that are
* to be executed this should be increased for accuracy.
*
* @param type this is the type of the worker threads
* @param size this is the number of threads for the scheduler
*/
public ConcurrentScheduler(Class type, int size) {
this.queue = new SchedulerQueue(type, size);
}
/**
* This will execute the task within the executor immediately
* as it uses a delay duration of zero milliseconds. This can
* be used if the scheduler is to be used as a thread pool.
*
* @param task this is the task to schedule for execution
*/
public void execute(Runnable task) {
queue.execute(task);
}
/**
* This will execute the task within the executor after the time
* specified has expired. If the time specified is zero then it
* will be executed immediately. Once the scheduler has been
* stopped then this method will no longer accept runnable tasks.
*
* @param task this is the task to schedule for execution
* @param delay the time in milliseconds to wait for execution
*/
public void execute(Runnable task, long delay) {
execute(task, delay, TimeUnit.MILLISECONDS);
}
/**
* This will execute the task within the executor after the time
* specified has expired. If the time specified is zero then it
* will be executed immediately. Once the scheduler has been
* stopped then this method will no longer accept runnable tasks.
*
* @param task this is the task to schedule for execution
* @param delay this is the delay to wait before execution
* @param unit this is the duration time unit to wait for
*/
public void execute(Runnable task, long delay, TimeUnit unit) {
queue.execute(task, delay, unit);
}
/**
* This is used to stop the scheduler by interrupting all running
* tasks and shutting down the threads within the pool. This will
* return immediately once it has been stopped, and not further
* tasks will be accepted by this pool for execution.
*/
public void stop() {
stop(60000);
}
/**
* This is used to stop the scheduler by interrupting all running
* tasks and shutting down the threads within the pool. This will
* return once it has been stopped, and no further tasks will be
* accepted by this pool for execution.
*
* @param wait the number of milliseconds to wait for it to stop
*/
public void stop(long wait) {
queue.stop(wait);
}
}
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