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 */
017 package org.apache.activemq.kaha.impl.async;
018
019 import java.io.File;
020 import java.io.FilenameFilter;
021 import java.io.IOException;
022 import java.util.ArrayList;
023 import java.util.Collections;
024 import java.util.List;
025
026 import org.apache.activemq.thread.Scheduler;
027 import org.apache.activemq.util.ByteSequence;
028 import org.slf4j.Logger;
029 import org.slf4j.LoggerFactory;
030
031 /**
032 * An AsyncDataManager that works in read only mode against multiple data directories.
033 * Useful for reading back archived data files.
034 */
035 public class ReadOnlyAsyncDataManager extends AsyncDataManager {
036
037 private static final Logger LOG = LoggerFactory.getLogger(ReadOnlyAsyncDataManager.class);
038 private final ArrayList<File> dirs;
039
040 public ReadOnlyAsyncDataManager(final ArrayList<File> dirs) {
041 this.dirs = dirs;
042 }
043
044 @SuppressWarnings("unchecked")
045 public synchronized void start() throws IOException {
046 if (started) {
047 return;
048 }
049
050 started = true;
051
052 accessorPool = new DataFileAccessorPool(this);
053
054 ArrayList<File> files = new ArrayList<File>();
055 for (File directory : dirs) {
056 final File d = directory;
057 File[] f = d.listFiles(new FilenameFilter() {
058 public boolean accept(File dir, String n) {
059 return dir.equals(d) && n.startsWith(filePrefix);
060 }
061 });
062 for (int i = 0; i < f.length; i++) {
063 files.add(f[i]);
064 }
065 }
066
067 for (File file : files) {
068 try {
069 String n = file.getName();
070 String numStr = n.substring(filePrefix.length(), n.length());
071 int num = Integer.parseInt(numStr);
072 DataFile dataFile = new ReadOnlyDataFile(file, num, preferedFileLength);
073 fileMap.put(dataFile.getDataFileId(), dataFile);
074 storeSize.addAndGet(dataFile.getLength());
075 } catch (NumberFormatException e) {
076 // Ignore file that do not match the pattern.
077 }
078 }
079
080 // Sort the list so that we can link the DataFiles together in the
081 // right order.
082 List<DataFile> dataFiles = new ArrayList<DataFile>(fileMap.values());
083 Collections.sort(dataFiles);
084 currentWriteFile = null;
085 for (DataFile df : dataFiles) {
086 if (currentWriteFile != null) {
087 currentWriteFile.linkAfter(df);
088 }
089 currentWriteFile = df;
090 fileByFileMap.put(df.getFile(), df);
091 }
092
093 // Need to check the current Write File to see if there was a partial
094 // write to it.
095 if (currentWriteFile != null) {
096
097 // See if the lastSyncedLocation is valid..
098 Location l = lastAppendLocation.get();
099 if (l != null && l.getDataFileId() != currentWriteFile.getDataFileId().intValue()) {
100 l = null;
101 }
102 }
103 }
104
105 public synchronized void close() throws IOException {
106 if (!started) {
107 return;
108 }
109 accessorPool.close();
110 fileMap.clear();
111 fileByFileMap.clear();
112 started = false;
113 }
114
115
116 public Location getFirstLocation() throws IllegalStateException, IOException {
117 if( currentWriteFile == null ) {
118 return null;
119 }
120
121 DataFile first = (DataFile)currentWriteFile.getHeadNode();
122 Location cur = new Location();
123 cur.setDataFileId(first.getDataFileId());
124 cur.setOffset(0);
125 cur.setSize(0);
126 return getNextLocation(cur);
127 }
128
129 @Override
130 public synchronized boolean delete() throws IOException {
131 throw new RuntimeException("Cannot delete a ReadOnlyAsyncDataManager");
132 }
133 }