| /** |
| * 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.kahadb.journal; |
| |
| import java.io.File; |
| import java.io.FilenameFilter; |
| import java.io.IOException; |
| import java.util.ArrayList; |
| import java.util.Collections; |
| import java.util.List; |
| |
| /** |
| * An AsyncDataManager that works in read only mode against multiple data directories. |
| * Useful for reading back archived data files. |
| */ |
| public class ReadOnlyJournal extends Journal { |
| |
| private final ArrayList<File> dirs; |
| |
| public ReadOnlyJournal(final ArrayList<File> dirs) { |
| this.dirs = dirs; |
| } |
| |
| public synchronized void start() throws IOException { |
| if (started) { |
| return; |
| } |
| |
| started = true; |
| |
| ArrayList<File> files = new ArrayList<File>(); |
| for (File directory : dirs) { |
| final File d = directory; |
| File[] f = d.listFiles(new FilenameFilter() { |
| public boolean accept(File dir, String n) { |
| return dir.equals(d) && n.startsWith(filePrefix); |
| } |
| }); |
| for (int i = 0; i < f.length; i++) { |
| files.add(f[i]); |
| } |
| } |
| |
| for (File file : files) { |
| try { |
| String n = file.getName(); |
| String numStr = n.substring(filePrefix.length(), n.length()); |
| int num = Integer.parseInt(numStr); |
| DataFile dataFile = new ReadOnlyDataFile(file, num, preferedFileLength); |
| fileMap.put(dataFile.getDataFileId(), dataFile); |
| totalLength.addAndGet(dataFile.getLength()); |
| } catch (NumberFormatException e) { |
| // Ignore file that do not match the pattern. |
| } |
| } |
| |
| // Sort the list so that we can link the DataFiles together in the |
| // right order. |
| List<DataFile> list = new ArrayList<DataFile>(fileMap.values()); |
| Collections.sort(list); |
| for (DataFile df : list) { |
| dataFiles.addLast(df); |
| fileByFileMap.put(df.getFile(), df); |
| } |
| |
| // // Need to check the current Write File to see if there was a partial |
| // // write to it. |
| // if (!dataFiles.isEmpty()) { |
| // |
| // // See if the lastSyncedLocation is valid.. |
| // Location l = lastAppendLocation.get(); |
| // if (l != null && l.getDataFileId() != dataFiles.getTail().getDataFileId().intValue()) { |
| // l = null; |
| // } |
| // |
| // // If we know the last location that was ok.. then we can skip lots |
| // // of checking |
| // try { |
| // l = recoveryCheck(dataFiles.getTail(), l); |
| // lastAppendLocation.set(l); |
| // } catch (IOException e) { |
| // LOG.warn("recovery check failed", e); |
| // } |
| // } |
| } |
| |
| public synchronized void close() throws IOException { |
| if (!started) { |
| return; |
| } |
| accessorPool.close(); |
| fileMap.clear(); |
| fileByFileMap.clear(); |
| started = false; |
| } |
| |
| |
| public Location getFirstLocation() throws IllegalStateException, IOException { |
| if( dataFiles.isEmpty() ) { |
| return null; |
| } |
| |
| DataFile first = dataFiles.getHead(); |
| Location cur = new Location(); |
| cur.setDataFileId(first.getDataFileId()); |
| cur.setOffset(0); |
| cur.setSize(0); |
| return getNextLocation(cur); |
| } |
| |
| @Override |
| public synchronized boolean delete() throws IOException { |
| throw new RuntimeException("Cannot delete a ReadOnlyAsyncDataManager"); |
| } |
| } |