001    // Copyright 2010, 2011 The Apache Software Foundation
002    //
003    // Licensed under the Apache License, Version 2.0 (the "License");
004    // you may not use this file except in compliance with the License.
005    // You may obtain a copy of the License at
006    //
007    // http://www.apache.org/licenses/LICENSE-2.0
008    //
009    // Unless required by applicable law or agreed to in writing, software
010    // distributed under the License is distributed on an "AS IS" BASIS,
011    // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
012    // See the License for the specific language governing permissions and
013    // limitations under the License.
014    
015    package org.apache.tapestry5.ioc;
016    
017    /**
018     * Configuration symbols used by the IoC container.
019     * 
020     * @since 5.2.2
021     */
022    public class IOCSymbols
023    {
024        /**
025         * The minimum size of the thread pool. The default is 3. When a task is created and there are fewer
026         * than this number of threads in the pool, a new thread is created for the task.
027         */
028        public static final String THREAD_POOL_CORE_SIZE = "tapestry.thread-pool.core-pool-size";
029    
030        /**
031         * The size of the task queue. When there are at least {@linkplain #THREAD_POOL_CORE_SIZE the core number} of
032         * threads in the pool, tasks will be placed in the queue. If the queue is empty, more threads
033         * may be created (up to the {@linkplain #THREAD_POOL_MAX_SIZE maximum pool size}). If the queue is full and
034         * all threads have been created, the task is rejected.
035         * <p>
036         * The default is 100.
037         * 
038         * @since 5.3
039         * @see <a href="http://www.bigsoft.co.uk/blog/index.php/2009/11/27/rules-of-a-threadpoolexecutor-pool-size">
040         *     Rules of a ThreadPoolExecutor pool size
041         *     </a>
042         */
043        public static final String THREAD_POOL_QUEUE_SIZE = "tapestry.thread-pool.queue-size";
044    
045        /**
046         * Maximium size of the thread pool, which defaults to 10.
047         */
048        public static final String THREAD_POOL_MAX_SIZE = "tapestry.thread-pool.max-pool-size";
049    
050        /**
051         * Time in milliseconds (via {@link org.apache.tapestry5.ioc.util.TimeInterval}) to keep waiting threads alive.
052         * Default is one minute.
053         */
054        public static final String THREAD_POOL_KEEP_ALIVE = "tapestry.thread-pool.keep-alive";
055    
056        /**
057         * By default, the {@link org.apache.tapestry5.ioc.services.ParallelExecutor} service uses a thread pool. In
058         * environments (such as Google Application Engine) where thread creation is not allowed, this can be set to
059         * "false", and deferred logic will, instead, execute immediately.
060         * 
061         * @since 5.1.0.3
062         */
063        public static final String THREAD_POOL_ENABLED = "tapestry.thread-pool-enabled";
064    }