/*
* CDDL HEADER START
*
* The contents of this file are subject to the terms of the
* Common Development and Distribution License, Version 1.0 only
* (the "License"). You may not use this file except in compliance
* with the License.
*
* You can obtain a copy of the license at
* trunk/opends/resource/legal-notices/OpenDS.LICENSE
* or https://OpenDS.dev.java.net/OpenDS.LICENSE.
* See the License for the specific language governing permissions
* and limitations under the License.
*
* When distributing Covered Code, include this CDDL HEADER in each
* file and include the License file at
* trunk/opends/resource/legal-notices/OpenDS.LICENSE. If applicable,
* add the following below this CDDL HEADER, with the fields enclosed
* by brackets "[]" replaced with your own identifying information:
* Portions Copyright [yyyy] [name of copyright owner]
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*
*
* Copyright 2006-2010 Sun Microsystems, Inc.
* Portions copyright 2013 ForgeRock AS.
*/
package org.opends.server.extensions;
import static org.opends.messages.ConfigMessages.*;
import static org.opends.messages.CoreMessages.*;
import static org.opends.server.loggers.ErrorLogger.*;
import static org.opends.server.loggers.debug.DebugLogger.*;
import java.util.ArrayList;
import java.util.List;
import java.util.concurrent.ConcurrentLinkedQueue;
import java.util.concurrent.Semaphore;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.atomic.AtomicLong;
import org.opends.messages.Message;
import org.opends.server.admin.server.ConfigurationChangeListener;
import org.opends.server.admin.std.server.ParallelWorkQueueCfg;
import org.opends.server.api.WorkQueue;
import org.opends.server.config.ConfigException;
import org.opends.server.core.DirectoryServer;
import org.opends.server.loggers.debug.DebugTracer;
import org.opends.server.monitors.ParallelWorkQueueMonitor;
import org.opends.server.types.CancelRequest;
import org.opends.server.types.ConfigChangeResult;
import org.opends.server.types.DebugLogLevel;
import org.opends.server.types.DirectoryException;
import org.opends.server.types.InitializationException;
import org.opends.server.types.Operation;
import org.opends.server.types.ResultCode;
/**
* This class defines a data structure for storing and interacting with the
* Directory Server work queue.
*/
public class ParallelWorkQueue
extends WorkQueue<ParallelWorkQueueCfg>
implements ConfigurationChangeListener<ParallelWorkQueueCfg>
{
/**
* The tracer object for the debug logger.
*/
private static final DebugTracer TRACER = getTracer();
/**
* The maximum number of times to retry getting the next operation from the
* queue if an unexpected failure occurs.
*/
private static final int MAX_RETRY_COUNT = 5;
/** The set of worker threads that will be used to process this work queue. */
private ArrayList<ParallelWorkerThread> workerThreads;
/**
* The number of operations that have been submitted to the work queue for
* processing.
*/
private AtomicLong opsSubmitted;
/**
* Indicates whether one or more of the worker threads needs to be killed at
* the next convenient opportunity.
*/
private boolean killThreads;
/** Indicates whether the Directory Server is shutting down. */
private boolean shutdownRequested;
/** The thread number used for the last worker thread that was created. */
private int lastThreadNumber;
/**
* The number of worker threads that should be active (or will be shortly if a
* configuration change has not been completely applied).
*/
private int numWorkerThreads;
/** The queue that will be used to actually hold the pending operations. */
private ConcurrentLinkedQueue<Operation> opQueue;
/** The lock used to provide threadsafe access for the queue. */
private final Object queueLock = new Object();
private final Semaphore queueSemaphore = new Semaphore(0, false);
/**
* Creates a new instance of this work queue. All initialization should be
* performed in the <CODE>initializeWorkQueue</CODE> method.
*/
public ParallelWorkQueue()
{
// No implementation should be performed here.
}
/**
* {@inheritDoc}
*/
@Override()
public void initializeWorkQueue(ParallelWorkQueueCfg configuration)
throws ConfigException, InitializationException
{
shutdownRequested = false;
killThreads = false;
opsSubmitted = new AtomicLong(0);
// Register to be notified of any configuration changes.
configuration.addParallelChangeListener(this);
// Get the necessary configuration from the provided entry.
numWorkerThreads =
computeNumWorkerThreads(configuration.getNumWorkerThreads());
// Create the actual work queue.
opQueue = new ConcurrentLinkedQueue<Operation>();
// Create the set of worker threads that should be used to service the
// work queue.
workerThreads = new ArrayList<ParallelWorkerThread>(numWorkerThreads);
for (lastThreadNumber = 0; lastThreadNumber < numWorkerThreads;
lastThreadNumber++)
{
ParallelWorkerThread t =
new ParallelWorkerThread(this, lastThreadNumber);
t.start();
workerThreads.add(t);
}
// Create and register a monitor provider for the work queue.
try
{
ParallelWorkQueueMonitor monitor =
new ParallelWorkQueueMonitor(this);
monitor.initializeMonitorProvider(null);
DirectoryServer.registerMonitorProvider(monitor);
}
catch (Exception e)
{
if (debugEnabled())
{
TRACER.debugCaught(DebugLogLevel.ERROR, e);
}
Message message = ERR_CONFIG_WORK_QUEUE_CANNOT_CREATE_MONITOR.get(
String.valueOf(ParallelWorkQueueMonitor.class), String.valueOf(e));
logError(message);
}
}
/**
* {@inheritDoc}
*/
@Override()
public void finalizeWorkQueue(Message reason)
{
shutdownRequested = true;
// Send responses to any operations in the pending queue to indicate that
// they won't be processed because the server is shutting down.
CancelRequest cancelRequest = new CancelRequest(true, reason);
ArrayList<Operation> pendingOperations = new ArrayList<Operation>();
opQueue.removeAll(pendingOperations);
for (Operation o : pendingOperations)
{
try
{
// The operation has no chance of responding to the cancel
// request so avoid waiting for a cancel response.
if (o.getCancelResult() == null) {
o.abort(cancelRequest);
}
}
catch (Exception e)
{
if (debugEnabled())
{
TRACER.debugCaught(DebugLogLevel.ERROR, e);
}
logError(WARN_QUEUE_UNABLE_TO_CANCEL.get(
String.valueOf(o), String.valueOf(e)));
}
}
// Notify all the worker threads of the shutdown.
for (ParallelWorkerThread t : workerThreads)
{
try
{
t.shutDown();
}
catch (Exception e)
{
if (debugEnabled())
{
TRACER.debugCaught(DebugLogLevel.ERROR, e);
}
logError(WARN_QUEUE_UNABLE_TO_NOTIFY_THREAD.get(
t.getName(), String.valueOf(e)));
}
}
}
/**
* Indicates whether this work queue has received a request to shut down.
*
* @return <CODE>true</CODE> if the work queue has recieved a request to shut
* down, or <CODE>false</CODE> if not.
*/
public boolean shutdownRequested()
{
return shutdownRequested;
}
/**
* Submits an operation to be processed by one of the worker threads
* associated with this work queue.
*
* @param operation The operation to be processed.
*
* @throws DirectoryException If the provided operation is not accepted for
* some reason (e.g., if the server is shutting
* down or the pending operation queue is already
* at its maximum capacity).
*/
@Override
public void submitOperation(Operation operation) throws DirectoryException
{
if (shutdownRequested)
{
Message message = WARN_OP_REJECTED_BY_SHUTDOWN.get();
throw new DirectoryException(ResultCode.UNAVAILABLE, message);
}
opQueue.add(operation);
queueSemaphore.release();
opsSubmitted.incrementAndGet();
}
/** {@inheritDoc} */
@Override
public boolean trySubmitOperation(Operation operation)
throws DirectoryException
{
submitOperation(operation);
return true;
}
/**
* Retrieves the next operation that should be processed by one of the worker
* threads, blocking if necessary until a new request arrives. This method
* should only be called by a worker thread associated with this work queue.
*
* @param workerThread The worker thread that is requesting the operation.
*
* @return The next operation that should be processed, or <CODE>null</CODE>
* if the server is shutting down and no more operations will be
* processed.
*/
public Operation nextOperation(ParallelWorkerThread workerThread)
{
return retryNextOperation(workerThread, 0);
}
/**
* Retrieves the next operation that should be processed by one of the worker
* threads following a previous failure attempt. A maximum of five
* consecutive failures will be allowed before returning <CODE>null</CODE>,
* which will cause the associated thread to exit.
*
* @param workerThread The worker thread that is requesting the operation.
* @param numFailures The number of consecutive failures that the worker
* thread has experienced so far. If this gets too
* high, then this method will return <CODE>null</CODE>
* rather than retrying.
*
* @return The next operation that should be processed, or <CODE>null</CODE>
* if the server is shutting down and no more operations will be
* processed, or if there have been too many consecutive failures.
*/
private Operation retryNextOperation(
ParallelWorkerThread workerThread,
int numFailures)
{
// See if we should kill off this thread. This could be necessary if the
// number of worker threads has been decreased with the server online. If
// so, then return null and the thread will exit.
if (killThreads)
{
synchronized (queueLock)
{
try
{
int currentThreads = workerThreads.size();
if (currentThreads > numWorkerThreads)
{
if (workerThreads.remove(Thread.currentThread()))
{
currentThreads--;
}
if (currentThreads <= numWorkerThreads)
{
killThreads = false;
}
workerThread.setStoppedByReducedThreadNumber();
return null;
}
}
catch (Exception e)
{
if (debugEnabled())
{
TRACER.debugCaught(DebugLogLevel.ERROR, e);
}
}
}
}
if ((shutdownRequested) || (numFailures > MAX_RETRY_COUNT))
{
if (numFailures > MAX_RETRY_COUNT)
{
Message message = ERR_CONFIG_WORK_QUEUE_TOO_MANY_FAILURES.get(
Thread.currentThread().getName(), numFailures, MAX_RETRY_COUNT);
logError(message);
}
return null;
}
try
{
while (true)
{
Operation nextOperation = null;
if (queueSemaphore.tryAcquire(5, TimeUnit.SECONDS)) {
nextOperation = opQueue.poll();
}
if (nextOperation == null)
{
// There was no work to do in the specified length of time. See if
// we should shutdown, and if not then just check again.
if (shutdownRequested)
{
return null;
}
else if (killThreads)
{
synchronized (queueLock)
{
try
{
int currentThreads = workerThreads.size();
if (currentThreads > numWorkerThreads)
{
if (workerThreads.remove(Thread.currentThread()))
{
currentThreads--;
}
if (currentThreads <= numWorkerThreads)
{
killThreads = false;
}
workerThread.setStoppedByReducedThreadNumber();
return null;
}
}
catch (Exception e)
{
if (debugEnabled())
{
TRACER.debugCaught(DebugLogLevel.ERROR, e);
}
}
}
}
}
else
{
return nextOperation;
}
}
}
catch (Exception e)
{
if (debugEnabled())
{
TRACER.debugCaught(DebugLogLevel.ERROR, e);
}
// This should not happen. The only recourse we have is to log a message
// and try again.
logError(WARN_WORKER_WAITING_UNCAUGHT_EXCEPTION.get(
Thread.currentThread().getName(), String.valueOf(e)));
return retryNextOperation(workerThread, numFailures + 1);
}
}
/**
* Attempts to remove the specified operation from this queue if it has not
* yet been picked up for processing by one of the worker threads.
*
* @param operation The operation to remove from the queue.
*
* @return <CODE>true</CODE> if the provided request was present in the queue
* and was removed successfully, or <CODE>false</CODE> it not.
*/
public boolean removeOperation(Operation operation)
{
return opQueue.remove(operation);
}
/**
* Retrieves the total number of operations that have been successfully
* submitted to this work queue for processing since server startup. This
* does not include operations that have been rejected for some reason like
* the queue already at its maximum capacity.
*
* @return The total number of operations that have been successfully
* submitted to this work queue since startup.
*/
public long getOpsSubmitted()
{
return opsSubmitted.longValue();
}
/**
* Retrieves the number of pending operations in the queue that have not yet
* been picked up for processing. Note that this method is not a
* constant-time operation and can be relatively inefficient, so it should be
* used sparingly.
*
* @return The number of pending operations in the queue that have not yet
* been picked up for processing.
*/
public int size()
{
return opQueue.size();
}
/**
* {@inheritDoc}
*/
@Override
public boolean isConfigurationChangeAcceptable(
ParallelWorkQueueCfg configuration,
List<Message> unacceptableReasons)
{
return true;
}
/**
* {@inheritDoc}
*/
@Override
public ConfigChangeResult applyConfigurationChange(
ParallelWorkQueueCfg configuration)
{
ArrayList<Message> resultMessages = new ArrayList<Message>();
int newNumThreads =
computeNumWorkerThreads(configuration.getNumWorkerThreads());
// Apply a change to the number of worker threads if appropriate.
int currentThreads = workerThreads.size();
if (newNumThreads != currentThreads)
{
synchronized (queueLock)
{
try
{
int threadsToAdd = newNumThreads - currentThreads;
if (threadsToAdd > 0)
{
for (int i = 0; i < threadsToAdd; i++)
{
ParallelWorkerThread t =
new ParallelWorkerThread(this, lastThreadNumber++);
workerThreads.add(t);
t.start();
}
killThreads = false;
}
else
{
killThreads = true;
}
numWorkerThreads = newNumThreads;
}
catch (Exception e)
{
if (debugEnabled())
{
TRACER.debugCaught(DebugLogLevel.ERROR, e);
}
}
}
}
return new ConfigChangeResult(ResultCode.SUCCESS, false, resultMessages);
}
/**
* {@inheritDoc}
*/
@Override()
public boolean isIdle()
{
if (opQueue.size() > 0) {
return false;
}
synchronized (queueLock)
{
for (ParallelWorkerThread t : workerThreads)
{
if (t.isActive())
{
return false;
}
}
return true;
}
}
/**
* Return the number of worker threads used by this WorkQueue.
*
* @return the number of worker threads used by this WorkQueue
*/
@Override
public int getNumWorkerThreads()
{
return this.numWorkerThreads;
}
}