/*
* 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.jackrabbit.core.journal;
import java.io.File;
import java.io.FilenameFilter;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Comparator;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* Represents a log file that can be rotated.
*/
public class RotatingLogFile implements Comparable<RotatingLogFile> {
/**
* Logger.
*/
private static Logger log = LoggerFactory.getLogger(RotatingLogFile.class);
/**
* Log extension.
*/
private static final String LOG_EXTENSION = "log";
/**
* Parent directory.
*/
private final File directory;
/**
* Basename.
*/
private final String basename;
/**
* Backing file.
*/
private final File file;
/**
* Version number.
*/
private int version;
/**
* Create a new instance of this class.
*
* @param file file itself
* @throws IllegalArgumentException if the filename is malformed
*/
private RotatingLogFile(File directory, String basename, File file)
throws IllegalArgumentException {
this.directory = directory;
this.basename = basename;
this.file = file;
parseName();
}
/**
* Parse the file name, ensuring that the file is actually made up
* of the components we expect.
*
* @throws IllegalArgumentException if the name is malformed
*/
private void parseName() throws IllegalArgumentException {
String name = file.getName();
int sep1 = name.indexOf('.');
if (sep1 == -1) {
throw new IllegalArgumentException("no dot in filename.");
}
if (!basename.equals(name.substring(0, sep1))) {
throw new IllegalArgumentException("name does not start with " +
basename + ".");
}
int sep2 = name.indexOf('.', sep1 + 1);
if (sep2 == -1) {
sep2 = name.length();
}
if (!LOG_EXTENSION.equals(name.substring(sep1 + 1, sep2))) {
throw new IllegalArgumentException("name does not contain " +
LOG_EXTENSION + ".");
}
if (sep2 < name.length()) {
String versionS = name.substring(sep2 + 1);
try {
version = Integer.parseInt(versionS);
} catch (NumberFormatException e) {
throw new IllegalArgumentException(
"extension is not a number: " + versionS);
}
}
}
/**
* Return the backing file.
*/
public File getFile() {
return file;
}
/**
* Rotate this file.
*/
public void rotate() {
String newName = basename +
"." + LOG_EXTENSION +
"." + String.valueOf(version + 1);
file.renameTo(new File(directory, newName));
}
/**
* Compares this log file to another file. It will return
* a negative number if this log file has a smaller version,
* a positive number if this log file a bigger version
* and <code>0</code> if they have the same version.
*/
public int compareTo(RotatingLogFile o) {
return version - o.version;
}
/**
* List all log files inside some directory. The list returned is
* guaranteed to be in descending order, i.e. it is safe to rotate
* every file in turn without accidentally overwriting another one.
*
* @param directory parent directory
* @param basename basename expected
* @return array of log files found
*/
public static RotatingLogFile[] listFiles(File directory, final String basename) {
File[] files = directory.listFiles(new FilenameFilter() {
public boolean accept(File dir, String name) {
return name.startsWith(basename + ".");
}
});
ArrayList<RotatingLogFile> l = new ArrayList<RotatingLogFile>();
for (int i = 0; i < files.length; i++) {
File file = files[i];
try {
l.add(new RotatingLogFile(directory, basename, file));
} catch (IllegalArgumentException e) {
log.warn("Bogusly named journal file, skipped: " + files[i] +
", reason: " + e.getMessage());
}
}
RotatingLogFile[] logFiles = new RotatingLogFile[l.size()];
l.toArray(logFiles);
Arrays.sort(logFiles, new Comparator<RotatingLogFile>() {
public int compare(RotatingLogFile o1, RotatingLogFile o2) {
return o2.compareTo(o1);
}
});
return logFiles;
}
}