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.kaha.impl.async;
018
019import java.io.File;
020import java.io.IOException;
021import java.io.RandomAccessFile;
022
023import org.apache.activemq.util.IOHelper;
024
025/**
026 * Allows you to open a data file in read only mode.  Useful when working with 
027 * archived data files.
028 */
029public class ReadOnlyDataFile extends DataFile {
030
031    ReadOnlyDataFile(File file, int number, int preferedSize) {
032        super(file, number, preferedSize);
033    }
034    
035    
036    public RandomAccessFile openRandomAccessFile(boolean appender) throws IOException {
037        RandomAccessFile rc = new RandomAccessFile(file, "r");
038        // When we start to write files size them up so that the OS has a chance
039        // to allocate the file contigously.
040        if (appender) {
041            if (length < preferedSize) {
042                rc.setLength(preferedSize);
043            }
044        }
045        return rc;
046    }
047
048    public void closeRandomAccessFile(RandomAccessFile file) throws IOException {
049        file.close();
050    }
051
052    public synchronized boolean delete() throws IOException {
053        throw new RuntimeException("Not valid on a read only file.");
054    }
055    
056    public synchronized void move(File targetDirectory) throws IOException{
057        throw new RuntimeException("Not valid on a read only file.");
058    }
059
060}