/*
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* CDDL HEADER START
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*
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* The contents of this file are subject to the terms of the
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* Common Development and Distribution License, Version 1.0 only
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* (the "License"). You may not use this file except in compliance
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* with the License.
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*
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* You can obtain a copy of the license at legal-notices/CDDLv1_0.txt
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* or http://forgerock.org/license/CDDLv1.0.html.
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* See the License for the specific language governing permissions
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* and limitations under the License.
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*
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* When distributing Covered Code, include this CDDL HEADER in each
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* file and include the License file at legal-notices/CDDLv1_0.txt.
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* If applicable, add the following below this CDDL HEADER, with the
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* fields enclosed by brackets "[]" replaced with your own identifying
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* information:
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* Portions Copyright [yyyy] [name of copyright owner]
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*
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* CDDL HEADER END
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*
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*
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* Copyright 2006-2010 Sun Microsystems, Inc.
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* Portions Copyright 2013-2014 ForgeRock AS.
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*/
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package org.opends.server.api;
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import static org.opends.messages.CoreMessages.*;
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import static org.opends.server.loggers.ErrorLogger.*;
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import org.forgerock.i18n.LocalizableMessage;
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import org.opends.server.admin.std.server.WorkQueueCfg;
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import org.opends.server.config.ConfigException;
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import org.opends.server.types.DirectoryException;
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import org.opends.server.types.InitializationException;
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import org.opends.server.types.Operation;
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/**
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* This class defines the structure and methods that must be
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* implemented by a Directory Server work queue. The work queue is
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* the component of the server that accepts requests from connection
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* handlers and ensures that they are properly processed. The manner
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* in which the work queue is able to accomplish this may vary between
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* implementations, but in general it is assumed that one or more
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* worker threads will be associated with the queue and may be used to
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* process requests in parallel.
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*
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* @param <T> The type of configuration handled by this work queue.
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*/
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@org.opends.server.types.PublicAPI(
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stability=org.opends.server.types.StabilityLevel.VOLATILE,
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mayInstantiate=false,
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mayExtend=true,
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mayInvoke=true)
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public abstract class WorkQueue<T extends WorkQueueCfg>
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{
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/**
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* Initializes this work queue based on the information in the
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* provided configuration entry.
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*
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* @param configuration The configuration to use to initialize
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* the work queue.
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*
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* @throws ConfigException If the provided configuration entry
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* does not have a valid work queue
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* configuration.
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*
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* @throws InitializationException If a problem occurs during
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* initialization that is not
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* related to the server
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* configuration.
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*/
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public abstract void initializeWorkQueue(T configuration)
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throws ConfigException, InitializationException;
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/**
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* Performs any necessary finalization for this work queue,
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* including ensuring that all active operations are interrupted or
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* will be allowed to complete, and that all pending operations will
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* be cancelled.
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*
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* @param reason The human-readable reason that the work queue is
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* being shut down.
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*/
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public abstract void finalizeWorkQueue(LocalizableMessage reason);
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/**
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* Submits an operation to be processed in the server.
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*
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* @param operation The operation to be processed.
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*
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* @throws DirectoryException If the provided operation is not
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* accepted for some reason (e.g., if
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* the server is shutting down or
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* already has too many pending
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* requests in the queue).
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*/
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public abstract void submitOperation(Operation operation)
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throws DirectoryException;
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/**
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* Tries to submit an operation to be processed in the server, without
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* blocking.
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*
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* @param operation
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* The operation to be processed.
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* @return true if the operation could be submitted to the queue, false if the
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* queue was full
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* @throws DirectoryException
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* If the provided operation is not accepted for some reason (e.g.,
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* if the server is shutting down).
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*/
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public abstract boolean trySubmitOperation(Operation operation)
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throws DirectoryException;
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/**
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* Indicates whether the work queue is currently processing any
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* requests. Note that this is a point-in-time determination, and
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* if any component of the server wishes to depend on a quiescent
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* state then it should use some external mechanism to ensure that
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* no other requests are submitted to the queue.
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*
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* @return {@code true} if the work queue is currently idle, or
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* {@code false} if it is being used to process one or more
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* operations.
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*/
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public abstract boolean isIdle();
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/**
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* Return the maximum number of worker threads that can be used by this
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* WorkQueue (The WorkQueue could have a thread pool which adjusts its size).
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*
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* @return the maximum number of worker threads that can be used by this
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* WorkQueue
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*/
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public abstract int getNumWorkerThreads();
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/**
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* Computes the number of worker threads to use by the working queue based on
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* the configured number.
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*
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* @param configuredNumWorkerThreads
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* the configured number of worker threads to use
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* @return the number of worker threads to use
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*/
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protected int computeNumWorkerThreads(Integer configuredNumWorkerThreads)
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{
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if (configuredNumWorkerThreads != null)
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{
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return configuredNumWorkerThreads;
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}
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else
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{
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// Automatically choose based on the number of processors.
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int cpus = Runtime.getRuntime().availableProcessors();
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int value = Math.max(24, cpus * 2);
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LocalizableMessage message = INFO_ERGONOMIC_SIZING_OF_WORKER_THREAD_POOL.get(value);
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logError(message);
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return value;
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}
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}
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/**
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* Waits for the work queue to become idle before returning. Note
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* that this is a point-in-time determination, and if any component
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* of the server wishes to depend on a quiescent state then it
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* should use some external mechanism to ensure that no other
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* requests are submitted to the queue.
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*
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* @param timeLimit The maximum length of time in milliseconds
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* that this method should wait for the queue to
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* become idle before giving up. A time limit
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* that is less than or equal to zero indicates
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* that there should not be a time limit.
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*
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* @return {@code true} if the work queue is idle at the time that
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* this method returns, or {@code false} if the wait time
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* limit was reached before the server became idle.
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*/
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public boolean waitUntilIdle(long timeLimit)
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{
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long stopWaitingTime;
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if (timeLimit <= 0)
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{
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stopWaitingTime = Long.MAX_VALUE;
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}
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else
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{
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stopWaitingTime = System.currentTimeMillis() + timeLimit;
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}
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while (System.currentTimeMillis() < stopWaitingTime)
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{
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if (isIdle())
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{
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return true;
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}
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try
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{
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Thread.sleep(1);
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} catch (InterruptedException ie) {}
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}
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return false;
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}
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}
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