org.quartz.spi.ThreadPool Maven / Gradle / Ivy
/*
* Copyright 2001-2009 Terracotta, Inc.
*
* 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.quartz.spi;
import org.quartz.SchedulerConfigException;
/**
*
* The interface to be implemented by classes that want to provide a thread
* pool for the {@link org.quartz.core.QuartzScheduler}'s use.
*
*
*
* ThreadPool implementation instances should ideally be made
* for the sole use of Quartz. Most importantly, when the method
* blockForAvailableThreads() returns a value of 1 or greater,
* there must still be at least one available thread in the pool when the
* method runInThread(Runnable) is called a few moments (or
* many moments) later. If this assumption does not hold true, it may
* result in extra JobStore queries and updates, and if clustering features
* are being used, it may result in greater imballance of load.
*
*
* @see org.quartz.core.QuartzScheduler
*
* @author James House
*/
public interface ThreadPool {
/*
* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
*
* Interface.
*
* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
*/
/**
*
* Execute the given {@link java.lang.Runnable} in the next
* available Thread.
*
*
*
* The implementation of this interface should not throw exceptions unless
* there is a serious problem (i.e. a serious misconfiguration). If there
* are no immediately available threads false should be returned.
*
*
* @return true, if the runnable was assigned to run on a Thread.
*/
boolean runInThread(Runnable runnable);
/**
*
* Determines the number of threads that are currently available in in
* the pool. Useful for determining the number of times
* runInThread(Runnable) can be called before returning
* false.
*
*
* The implementation of this method should block until there is at
* least one available thread.
*
* @return the number of currently available threads
*/
int blockForAvailableThreads();
/**
*
* Must be called before the ThreadPool is
* used, in order to give the it a chance to initialize.
*
*
* Typically called by the SchedulerFactory.
*/
void initialize() throws SchedulerConfigException;
/**
*
* Called by the QuartzScheduler to inform the ThreadPool
* that it should free up all of it's resources because the scheduler is
* shutting down.
*
*/
void shutdown(boolean waitForJobsToComplete);
/**
* Get the current number of threads in the ThreadPool.
*/
int getPoolSize();
/**
* Inform the ThreadPool of the Scheduler instance's Id,
* prior to initialize being invoked.
*
* @since 1.7
*/
void setInstanceId(String schedInstId);
/**
* Inform the ThreadPool of the Scheduler instance's name,
* prior to initialize being invoked.
*
* @since 1.7
*/
void setInstanceName(String schedName);
}