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