| /* |
| * |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you under the Apache License, Version 2.0 (the |
| * "License"); you may not use this file except in compliance |
| * with the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, |
| * software distributed under the License is distributed on an |
| * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY |
| * KIND, either express or implied. See the License for the |
| * specific language governing permissions and limitations |
| * under the License. |
| * |
| */ |
| package org.apache.qpid.server.queue; |
| |
| import java.security.AccessControlContext; |
| import java.util.concurrent.atomic.AtomicBoolean; |
| import java.util.concurrent.atomic.AtomicInteger; |
| import java.util.concurrent.atomic.AtomicLong; |
| |
| import org.slf4j.Logger; |
| import org.slf4j.LoggerFactory; |
| |
| import org.apache.qpid.server.util.ConnectionScopedRuntimeException; |
| |
| /** |
| * QueueRunners are Runnables used to process a queue when requiring |
| * asynchronous message delivery to consumers, which is necessary |
| * when straight-through delivery of a message to a consumer isn't |
| * possible during the enqueue operation. |
| */ |
| public class QueueRunner implements Runnable |
| { |
| private static final Logger _logger = LoggerFactory.getLogger(QueueRunner.class); |
| |
| private final AbstractQueue _queue; |
| |
| private static int IDLE = 0; |
| private static int SCHEDULED = 1; |
| private static int RUNNING = 2; |
| |
| private final AtomicInteger _scheduled = new AtomicInteger(IDLE); |
| |
| private final AtomicBoolean _stateChange = new AtomicBoolean(); |
| |
| private final AtomicLong _lastRunAgain = new AtomicLong(); |
| private final AtomicLong _lastRunTime = new AtomicLong(); |
| private final AccessControlContext _context; |
| private final String _taskName; |
| |
| public QueueRunner(AbstractQueue queue, AccessControlContext context) |
| { |
| _queue = queue; |
| _context = context; |
| _taskName = "Queue Runner[" + _queue.getName() + "]"; |
| } |
| |
| @Override |
| public void run() |
| { |
| if(_scheduled.compareAndSet(SCHEDULED,RUNNING)) |
| { |
| long runAgain = Long.MIN_VALUE; |
| _stateChange.set(false); |
| try |
| { |
| runAgain = _queue.processQueue(QueueRunner.this); |
| } |
| catch (ConnectionScopedRuntimeException e) |
| { |
| final String errorMessage = "Problem during asynchronous delivery by " + toString(); |
| if(_logger.isDebugEnabled()) |
| { |
| _logger.debug(errorMessage, e); |
| } |
| else |
| { |
| _logger.info(errorMessage + ' ' + e.getMessage()); |
| } |
| } |
| finally |
| { |
| _scheduled.compareAndSet(RUNNING, IDLE); |
| final long stateChangeCount = _queue.getStateChangeCount(); |
| _lastRunAgain.set(runAgain); |
| _lastRunTime.set(System.nanoTime()); |
| if(runAgain == 0L || runAgain != stateChangeCount || _stateChange.compareAndSet(true,false)) |
| { |
| if(_scheduled.compareAndSet(IDLE, SCHEDULED)) |
| { |
| _queue.execute(_taskName, QueueRunner.this, _context); |
| } |
| } |
| } |
| } |
| } |
| |
| @Override |
| public String toString() |
| { |
| return "QueueRunner-" + _queue.getLogSubject().toLogString(); |
| } |
| |
| public void execute() |
| { |
| _stateChange.set(true); |
| if(_scheduled.compareAndSet(IDLE, SCHEDULED)) |
| { |
| _queue.execute(_taskName, this, _context); |
| } |
| } |
| |
| public boolean isIdle() |
| { |
| return _scheduled.get() == IDLE; |
| } |
| |
| } |