001/**
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements.  See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License.  You may obtain a copy of the License at
008 *
009 *      http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017package org.apache.activemq.transport.reliable;
018
019import java.io.IOException;
020import java.util.HashMap;
021import java.util.Map;
022
023import org.slf4j.Logger;
024import org.slf4j.LoggerFactory;
025
026/**
027 * 
028 * 
029 */
030public class DefaultReplayBuffer implements ReplayBuffer {
031
032    private static final Logger LOG = LoggerFactory.getLogger(DefaultReplayBuffer.class);
033
034    private final int size;
035    private ReplayBufferListener listener;
036    private Map<Integer, Object> map;
037    private int lowestCommandId = 1;
038    private Object lock = new Object();
039
040    public DefaultReplayBuffer(int size) {
041        this.size = size;
042        map = createMap(size);
043    }
044
045    public void addBuffer(int commandId, Object buffer) {
046        if (LOG.isDebugEnabled()) {
047            LOG.debug("Adding command ID: " + commandId + " to replay buffer: " + this + " object: " + buffer);
048        }
049        synchronized (lock) {
050            int max = size - 1;
051            while (map.size() >= max) {
052                // lets find things to evict
053                Object evictedBuffer = map.remove(Integer.valueOf(++lowestCommandId));
054                onEvictedBuffer(lowestCommandId, evictedBuffer);
055            }
056            map.put(Integer.valueOf(commandId), buffer);
057        }
058    }
059
060    public void setReplayBufferListener(ReplayBufferListener bufferPoolAdapter) {
061        this.listener = bufferPoolAdapter;
062    }
063
064    public void replayMessages(int fromCommandId, int toCommandId, Replayer replayer) throws IOException {
065        if (replayer == null) {
066            throw new IllegalArgumentException("No Replayer parameter specified");
067        }
068        if (LOG.isDebugEnabled()) {
069            LOG.debug("Buffer: " + this + " replaying messages from: " + fromCommandId + " to: " + toCommandId);
070        }
071        for (int i = fromCommandId; i <= toCommandId; i++) {
072            Object buffer = null;
073            synchronized (lock) {
074                buffer = map.get(Integer.valueOf(i));
075            }
076            replayer.sendBuffer(i, buffer);
077        }
078    }
079
080    protected Map<Integer, Object> createMap(int maximumSize) {
081        return new HashMap<Integer, Object>(maximumSize);
082    }
083
084    protected void onEvictedBuffer(int commandId, Object buffer) {
085        if (listener != null) {
086            listener.onBufferDiscarded(commandId, buffer);
087        }
088    }
089}