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
015package org.apache.tapestry5.ioc;
016
017/**
018 * Configuration symbols used by the IoC container.
019 * 
020 * @since 5.2.2
021 */
022public 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}