| /* |
| * |
| * 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 org.apache.qpid.server.message.ServerMessage; |
| import org.apache.qpid.server.store.MessageEnqueueRecord; |
| |
| abstract public class PriorityQueueList extends OrderedQueueEntryList |
| { |
| |
| |
| public static PriorityQueueList newInstance(PriorityQueueImpl queue) |
| { |
| return new PriorityQueueMasterList(queue, queue.getPriorities()); |
| } |
| |
| public PriorityQueueList(final PriorityQueueImpl queue, |
| final HeadCreator headCreator) |
| { |
| super(queue, queue.getQueueStatistics(), headCreator); |
| } |
| |
| static class PriorityQueueMasterList extends PriorityQueueList |
| { |
| private static final HeadCreator DUMMY_HEAD_CREATOR = |
| new HeadCreator() |
| { |
| @Override |
| public PriorityQueueEntry createHead(final QueueEntryList list) |
| { |
| return null; |
| } |
| }; |
| private final PriorityQueueImpl _queue; |
| private final PriorityQueueEntrySubList[] _priorityLists; |
| private final int _priorities; |
| private final int _priorityOffset; |
| |
| public PriorityQueueMasterList(PriorityQueueImpl queue, int priorities) |
| { |
| super(queue, DUMMY_HEAD_CREATOR); |
| _queue = queue; |
| _priorityLists = new PriorityQueueEntrySubList[priorities]; |
| _priorities = priorities; |
| _priorityOffset = 5-((priorities + 1)/2); |
| for(int i = 0; i < priorities; i++) |
| { |
| _priorityLists[i] = new PriorityQueueEntrySubList(queue, i); |
| } |
| } |
| |
| public int getPriorities() |
| { |
| return _priorities; |
| } |
| |
| @Override |
| public PriorityQueueImpl getQueue() |
| { |
| return _queue; |
| } |
| |
| @Override |
| public PriorityQueueEntry add(ServerMessage message, final MessageEnqueueRecord enqueueRecord) |
| { |
| int index = message.getMessageHeader().getPriority() - _priorityOffset; |
| if(index >= _priorities) |
| { |
| index = _priorities-1; |
| } |
| else if(index < 0) |
| { |
| index = 0; |
| } |
| return (PriorityQueueEntry) _priorityLists[index].add(message, enqueueRecord); |
| |
| } |
| |
| @Override |
| protected PriorityQueueEntry createQueueEntry(final ServerMessage<?> message, |
| final MessageEnqueueRecord enqueueRecord) |
| { |
| throw new UnsupportedOperationException(); |
| } |
| |
| @Override |
| public PriorityQueueEntry next(QueueEntry node) |
| { |
| PriorityQueueEntry next = (PriorityQueueEntry) node.getNextValidEntry(); |
| |
| if(next == null) |
| { |
| final PriorityQueueList nodeEntryList = (PriorityQueueList) ((PriorityQueueEntry)node).getQueueEntryList(); |
| int index; |
| for(index = _priorityLists.length-1; _priorityLists[index] != nodeEntryList; index--) |
| { |
| // do nothing loop is just to find the index |
| } |
| |
| while(next == null && index != 0) |
| { |
| index--; |
| next = (PriorityQueueEntry) _priorityLists[index].getHead().getNextValidEntry(); |
| } |
| |
| } |
| return next; |
| } |
| |
| private final class PriorityQueueEntryListIterator implements QueueEntryIterator |
| { |
| private final QueueEntryIterator[] _iterators = new QueueEntryIterator[ _priorityLists.length ]; |
| private PriorityQueueEntry _lastNode; |
| |
| PriorityQueueEntryListIterator() |
| { |
| for(int i = 0; i < _priorityLists.length; i++) |
| { |
| _iterators[i] = _priorityLists[i].iterator(); |
| } |
| _lastNode = (PriorityQueueEntry) _iterators[_iterators.length - 1].getNode(); |
| } |
| |
| @Override |
| public boolean atTail() |
| { |
| for(int i = 0; i < _iterators.length; i++) |
| { |
| if(!_iterators[i].atTail()) |
| { |
| return false; |
| } |
| } |
| return true; |
| } |
| |
| @Override |
| public PriorityQueueEntry getNode() |
| { |
| return _lastNode; |
| } |
| |
| @Override |
| public boolean advance() |
| { |
| for(int i = _iterators.length-1; i >= 0; i--) |
| { |
| if(_iterators[i].advance()) |
| { |
| _lastNode = (PriorityQueueEntry) _iterators[i].getNode(); |
| return true; |
| } |
| } |
| return false; |
| } |
| } |
| |
| @Override |
| public PriorityQueueEntryListIterator iterator() |
| { |
| |
| return new PriorityQueueEntryListIterator(); |
| } |
| |
| @Override |
| public PriorityQueueEntry getHead() |
| { |
| return (PriorityQueueEntry) _priorityLists[_priorities-1].getHead(); |
| } |
| |
| @Override |
| public PriorityQueueEntry getTail() |
| { |
| return (PriorityQueueEntry) _priorityLists[0].getTail(); |
| } |
| |
| |
| |
| @Override |
| public void entryDeleted(final QueueEntry queueEntry) |
| { |
| |
| } |
| |
| @Override |
| public QueueEntry getOldestEntry() |
| { |
| QueueEntry oldest = null; |
| for(PriorityQueueEntrySubList subList : _priorityLists) |
| { |
| QueueEntry subListOldest = subList.getOldestEntry(); |
| if(oldest == null || (subListOldest != null && subListOldest.getMessage().getMessageNumber() < oldest.getMessage().getMessageNumber())) |
| { |
| oldest = subListOldest; |
| } |
| } |
| return oldest; |
| } |
| } |
| |
| static class PriorityQueueEntrySubList extends PriorityQueueList |
| { |
| private static final HeadCreator HEAD_CREATOR = new HeadCreator() |
| { |
| @Override |
| public PriorityQueueEntry createHead(final QueueEntryList list) |
| { |
| return new PriorityQueueEntry((PriorityQueueList) list); |
| } |
| }; |
| private int _listPriority; |
| |
| public PriorityQueueEntrySubList(PriorityQueueImpl queue, int listPriority) |
| { |
| super(queue, HEAD_CREATOR); |
| _listPriority = listPriority; |
| } |
| |
| @Override |
| protected PriorityQueueEntry createQueueEntry(ServerMessage<?> message, |
| final MessageEnqueueRecord enqueueRecord) |
| { |
| return new PriorityQueueEntry(this, message, enqueueRecord); |
| } |
| |
| public int getListPriority() |
| { |
| return _listPriority; |
| } |
| } |
| |
| static class PriorityQueueEntry extends OrderedQueueEntry |
| { |
| private PriorityQueueEntry(final PriorityQueueList queueEntryList) |
| { |
| super(queueEntryList); |
| } |
| |
| public PriorityQueueEntry(PriorityQueueEntrySubList queueEntryList, |
| ServerMessage<?> message, |
| final MessageEnqueueRecord messageEnqueueRecord) |
| { |
| super(queueEntryList, message, messageEnqueueRecord); |
| } |
| |
| @Override |
| public int compareTo(final QueueEntry o) |
| { |
| PriorityQueueEntry other = (PriorityQueueEntry)o; |
| PriorityQueueEntrySubList pqel = (PriorityQueueEntrySubList)other.getQueueEntryList(); |
| int otherPriority = pqel.getListPriority(); |
| int thisPriority = ((PriorityQueueEntrySubList) getQueueEntryList()).getListPriority(); |
| |
| if(thisPriority != otherPriority) |
| { |
| /* |
| * Different priorities, so answer can only be greater than or less than |
| * |
| * A message with higher priority (e.g. 5) is conceptually 'earlier' in the |
| * priority queue than one with a lower priority (e.g. 4). |
| */ |
| return thisPriority > otherPriority ? -1 : 1; |
| } |
| else |
| { |
| return super.compareTo(o); |
| } |
| } |
| } |
| } |