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.kahadb.journal;
018    
019    import java.io.File;
020    import java.io.IOException;
021    import java.io.RandomAccessFile;
022    
023    /**
024     * Allows you to open a data file in read only mode.  Useful when working with 
025     * archived data files.
026     */
027    public class ReadOnlyDataFile extends DataFile {
028    
029        ReadOnlyDataFile(File file, int number, int preferedSize) {
030            super(file, number, preferedSize);
031        }
032        
033        public RandomAccessFile openRandomAccessFile(boolean appender) throws IOException {
034            return new RandomAccessFile(file, "r");
035        }
036    
037        public void closeRandomAccessFile(RandomAccessFile file) throws IOException {
038            file.close();
039        }
040    
041        public synchronized boolean delete() throws IOException {
042            throw new RuntimeException("Not valid on a read only file.");
043        }
044        
045        public synchronized void move(File targetDirectory) throws IOException{
046            throw new RuntimeException("Not valid on a read only file.");
047        }
048    
049    }