001/*
002 * ModeShape (http://www.modeshape.org)
003 *
004 * Licensed under the Apache License, Version 2.0 (the "License");
005 * you may not use this file except in compliance with the License.
006 * You may obtain a copy of the License at
007 *
008 *       http://www.apache.org/licenses/LICENSE-2.0
009 *
010 * Unless required by applicable law or agreed to in writing, software
011 * distributed under the License is distributed on an "AS IS" BASIS,
012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013 * See the License for the specific language governing permissions and
014 * limitations under the License.
015 */
016package org.modeshape.common.util;
017
018import java.util.concurrent.ExecutorService;
019import java.util.concurrent.ScheduledExecutorService;
020import java.util.concurrent.TimeUnit;
021
022/**
023 * Factory interface for creating/obtaining named thread pools.
024 */
025public interface ThreadPoolFactory {
026
027    /**
028     * Obtain a thread pool with the supplied name, or create and return one if no thread pool exists with that name. When
029     * finished with the thread pool, it should be {@link #releaseThreadPool released}.
030     * 
031     * @param name the name of the thread pool; may not be null
032     * @return the thread pool executor; never null
033     */
034    ExecutorService getThreadPool( String name );
035
036    /**
037     * Signal that the supplied thread pool is no longer needed. Obtain a cached thread pool with the supplied name, or create and
038     * return one if no thread pool exists with that name. When finished with the thread pool, it should be
039     * {@link #releaseThreadPool released}.
040     * 
041     * @param maxPoolSize the maximum number of threads that can be spawned by this pool.
042     * @param name the name of the thread pool; may not be null
043     * @return the thread pool executor; never null
044     */
045    ExecutorService getCachedTreadPool( String name, int maxPoolSize );
046
047    /**
048     * Obtain a scheduled thread pool with the supplied name, or create and return one if no thread pool exists with that name.
049     * When finished with the thread pool, it should be {@link #releaseThreadPool released}.
050     * 
051     * @param name the name of the thread pool; may not be null
052     * @return the thread pool executor; never null
053     */
054    ScheduledExecutorService getScheduledThreadPool( String name );
055
056    /**
057     * Performs a {@link java.util.concurrent.ExecutorService#shutdownNow()} on the given pool, if the pool has been created
058     * previously by this class. Clients which use this method should handle, if necessary, any potential
059     * {@link InterruptedException}
060     * 
061     * @param pool the pool that is no longer needed
062     */
063    void releaseThreadPool( ExecutorService pool );
064
065    /**
066     * Terminates all the existing thread pool, by waiting for them maximum {@code maxWaitTimeMillis} milliseconds, after which
067     * calling {@link java.util.concurrent.ExecutorService#shutdownNow()}.
068     * 
069     * @param maxWaitTime the maximum amount of time that should be given to the pools to shutdown on their own; must be
070     *        non-negative
071     * @param timeUnit the unit of time for the {@code maxWaitTime} parameter
072     */
073    void terminateAllPools( long maxWaitTime,
074                            TimeUnit timeUnit );
075}