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/*
Calimero 2 - A library for KNX network access
Copyright (c) 2006, 2011 B. Malinowsky
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
Linking this library statically or dynamically with other modules is
making a combined work based on this library. Thus, the terms and
conditions of the GNU General Public License cover the whole
combination.
As a special exception, the copyright holders of this library give you
permission to link this library with independent modules to produce an
executable, regardless of the license terms of these independent
modules, and to copy and distribute the resulting executable under terms
of your choice, provided that you also meet, for each linked independent
module, the terms and conditions of the license of that module. An
independent module is a module which is not derived from or based on
this library. If you modify this library, you may extend this exception
to your version of the library, but you are not obligated to do so. If
you do not wish to do so, delete this exception statement from your
version.
*/
package tuwien.auto.calimero.log;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
/**
* A LogWriter using a file resource as output destination for log information.
*
* A file name is supplied on creation of this log writer, the file is opened and used for
* further logging. After {@link #close()}ing the log writer, it cannot be opened
* anymore.
* For output the platform's default character set is used.
* A maximum allowed file size may be specified to prevent file size explosion. If the
* size limit is reached, the file content is deleted before any new output.
*
* @author B. Malinowsky
*/
public class LogFileWriter extends LogStreamWriter
{
// we do a distinction of the used default character set
// for easier calculation of file size
private static final int byteEnc;
private static final int lineSep;
static {
// get line separator size
lineSep = System.getProperty("line.separator").length();
// get character encoding byte size
byte[] buf = new String(new char[] { ' ', ' ' }).getBytes();
// if length is 4 or 6 (with byte order mark) we have UTF-16
if (buf.length == 4 || buf.length == 6)
byteEnc = 2;
else {
// check for UTF-8 with a character encoded in more bytes
buf = new String(new char[] { '\uFFFF' }).getBytes();
// on length == 1 we have single byte encoding
if (buf.length == 1)
byteEnc = 1;
else
byteEnc = 3;
}
}
private String file;
// log file size in bytes
private int logSize;
// maximum allowed log file size in bytes
private int maxSize;
/**
* Creates a LogFileWriter to write to the output file named by file
* and open the file according to append.
*
*
* @param file file name in the file system to open or create, the path to the file
* has to exist
* @param append set this true to append output at end of file, or false to start
* writing into an empty file at the beginning
* @throws KNXLogException if path to file does not exist, if file can not be created
* or opened
*/
public LogFileWriter(final String file, final boolean append) throws KNXLogException
{
if (append) {
// if file does not exist, we will fail later anyway...
final File f = new File(file);
logSize = (int) f.length();
}
this.file = file;
formatOutput = false;
try {
createWriter(new FileOutputStream(file, append));
}
catch (final FileNotFoundException e) {
throw new KNXLogException("open log file " + file + ": " + e.getMessage(), e);
}
catch (final SecurityException e) {
throw new KNXLogException("open log file " + file + ": " + e.getMessage(), e);
}
}
/**
* Like {@link #LogFileWriter(String, boolean)}, with the option to adjust the
* automatic flush behavior of data.
*
*
* @param file file name in the file system to open or create
* @param append set this true to append output at end of file, or false to start
* writing into an empty file at the beginning
* @param autoFlush set true to force data be immediately written to file after every
* write() call, set false to buffer data and flush only on full buffer
* @throws KNXLogException if file can not be created or opened
*/
public LogFileWriter(final String file, final boolean append, final boolean autoFlush)
throws KNXLogException
{
this(file, append);
this.autoFlush = autoFlush;
}
/**
* Like {@link #LogFileWriter(String, boolean)}, with the option to adjust the filter
* log level for information logged by LogFileWriter.
*
*
* @param level log level used by this LogWriter to filter log information
* @param file file name in the file system to open or create
* @param append set this true to append output at end of file, or false to start
* writing into an empty file at the beginning
* @throws KNXLogException if file can not be created or opened
*/
public LogFileWriter(final LogLevel level, final String file, final boolean append)
throws KNXLogException
{
this(file, append);
setLogLevel(level);
}
/**
* Like {@link #LogFileWriter(LogLevel, String, boolean)}, with the option to specify
* the maximum file size allowed for all output written.
*
* During opening of file, the file size is checked to be smaller than
* maxSize, otherwise the file content is erased.
* If a call to write() would exceed the maximum file size specified, the file content
* is erased before the new log information is written.
*
* @param level log level used by this LogWriter to filter log information
* @param file file name in the file system to open or create
* @param append set this true to append output at end of file, or false to start
* writing into an empty file at the beginning
* @param maxSize maximum file size generated by this LogFileWriter
* @throws KNXLogException if file can not be created or opened
*/
public LogFileWriter(final LogLevel level, final String file, final boolean append,
final int maxSize) throws KNXLogException
{
this(level, file, append);
setMaxSize(maxSize);
ensureMaxSize("");
}
/**
* Like {@link #LogFileWriter(LogLevel, String, boolean, int)}, with the option to
* adjust the automatic flush behavior of data.
*
*
* @param level log level used by this LogWriter to filter log information
* @param file file name in the file system to open or create
* @param append set this true to append output at end of file, or false to start
* writing into an empty file at the beginning
* @param maxSize maximum file size generated by this LogFileWriter
* @param autoFlush set true to force data be immediately written to file after every
* write() call, set false to buffer data and flush only on full buffer
* @throws KNXLogException if file can not be created or opened
*/
public LogFileWriter(final LogLevel level, final String file, final boolean append,
final int maxSize, final boolean autoFlush) throws KNXLogException
{
this(level, file, append, maxSize);
this.autoFlush = autoFlush;
}
/**
* Returns the file name of the file resource used by this LogFileWriter or "" if the
* log writer has already been closed.
*
* The file name is the same as supplied on creation of this LogWriter, no path
* resolving etc. was done.
*
* @return file name
*/
public final String getFileName()
{
return file;
}
/**
* Sets the maximum allowed file size generated by this LogFileWriter.
*
* The value is only set if size >= 0.
* If size has a value of 0, no file size limit is enforced.
*
* @param size new allowed file size in bytes
*/
public final void setMaxSize(final int size)
{
if (size >= 0)
maxSize = size;
}
/**
* Returns the maximum allowed file size generated by this LogFileWriter, or 0 if no
* maximum was set.
*
*
* @return maximum file size in bytes
*/
public final int getMaxSize()
{
return maxSize;
}
/* (non-Javadoc)
* @see tuwien.auto.calimero.log.LogStreamWriter#write
* (java.lang.String, tuwien.auto.calimero.log.LogLevel, java.lang.String)
*/
public void write(final String logService, final LogLevel level, final String msg)
{
doFileWrite(logService, level, msg, null);
}
/* (non-Javadoc)
* @see tuwien.auto.calimero.log.LogStreamWriter#write
* (java.lang.String, tuwien.auto.calimero.log.LogLevel, java.lang.String,
* java.lang.Throwable)
*/
public void write(final String logService, final LogLevel level, final String msg,
final Throwable t)
{
doFileWrite(logService, level, msg, t);
}
/* (non-Javadoc)
* @see tuwien.auto.calimero.log.LogStreamWriter#close()
*/
public void close()
{
super.close();
file = "";
}
private void doFileWrite(final String logService, final LogLevel level, final String msg,
final Throwable t)
{
if (isLoggable(level)) {
final String s = formatOutput(logService, level, msg, t);
ensureMaxSize(s);
synchronized (this) {
super.write(logService, level, s);
logSize += getByteLength(s) + lineSep;
}
}
}
private void ensureMaxSize(final String msg)
{
if (maxSize == 0)
return;
synchronized (this) {
if (logSize + getByteLength(msg) + lineSep > maxSize) {
// remember used file name
final String fileName = file;
close();
try {
// no append, to reset file length to 0
createWriter(new FileOutputStream(fileName));
file = fileName;
logSize = 0;
}
catch (final FileNotFoundException e) {
getErrorHandler().error(this, "on creation of file " + fileName, e);
}
catch (final SecurityException e) {
getErrorHandler().error(this, "access denied", e);
}
}
}
}
private int getByteLength(final String s)
{
if (byteEnc == 1)
return s.length();
if (byteEnc == 2)
return s.length() * 2;
return s.getBytes().length;
}
}