dlr 01/08/21 13:48:47
Added: util/src/java/org/apache/commons/util
LockableFileWriter.java
Log:
Added Michael Salmon's FileWriter implementation, which creates honors
a lock file. Made some minor modifications of my own.
Revision Changes Path
1.1
jakarta-commons-sandbox/util/src/java/org/apache/commons/util/LockableFileWriter.java
Index: LockableFileWriter.java
===================================================================
package org.apache.commons.util;
/* ====================================================================
* The Apache Software License, Version 1.1
*
* Copyright (c) 2001 The Apache Software Foundation. All rights
* reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* 3. The end-user documentation included with the redistribution,
* if any, must include the following acknowledgment:
* "This product includes software developed by the
* Apache Software Foundation (http://www.apache.org/)."
* Alternately, this acknowledgment may appear in the software itself,
* if and wherever such third-party acknowledgments normally appear.
*
* 4. The names "Apache" and "Apache Software Foundation" and
* "Apache Turbine" must not be used to endorse or promote products
* derived from this software without prior written permission. For
* written permission, please contact [EMAIL PROTECTED]
*
* 5. Products derived from this software may not be called "Apache",
* "Apache Turbine", nor may "Apache" appear in their name, without
* prior written permission of the Apache Software Foundation.
*
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
* ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
* USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
* ====================================================================
*
* This software consists of voluntary contributions made by many
* individuals on behalf of the Apache Software Foundation. For more
* information on the Apache Software Foundation, please see
* <http://www.apache.org/>.
*/
import java.io.File;
import java.io.Writer;
import java.io.FileWriter;
import java.io.IOException;
/**
* A <code>FileWriter</code> that will create and honor lock files to
* allow simple cross thread file lock handling.
*
* @author <a href="mailto:[EMAIL PROTECTED]";>Michael Salmon</a>
* @author <a href="mailto:[EMAIL PROTECTED]";>Daniel Rall</a>
* @version $Id: LockableFileWriter.java,v 1.1 2001/08/21 20:48:47 dlr Exp $
*/
public class LockableFileWriter extends Writer
{
private static final String LCK = ".lck";
private File lockFile = null;
private FileWriter writer = null;
private String fileName = null;
private String lockDir = null;
public LockableFileWriter (String fileName)
throws IOException
{
this.fileName = fileName;
createLock();
this.writer = new FileWriter(fileName);
}
public LockableFileWriter (String fileName, String lockDir)
throws IOException
{
this.fileName = fileName;
this.lockDir = lockDir;
createLock();
this.writer = new FileWriter(fileName);
}
public LockableFileWriter (String fileName, boolean append)
throws IOException
{
this.fileName = fileName;
createLock();
this.writer = new FileWriter(fileName, append);
}
public LockableFileWriter (String fileName, boolean append, String lockDir)
throws IOException
{
this.fileName = fileName;
this.lockDir = lockDir;
createLock();
this.writer = new FileWriter(fileName, append);
}
public LockableFileWriter (File file)
throws IOException
{
this.fileName = file.getPath();
createLock();
this.writer = new FileWriter(file);
}
public LockableFileWriter (File file, String lockDir)
throws IOException
{
this.fileName = file.getPath();
this.lockDir = lockDir;
createLock();
this.writer = new FileWriter(file);
}
private void createLock()
throws IOException
{
synchronized (LockableFileWriter.class)
{
File lock = new File(lockDir, fileName + LCK);
if (lock.exists())
{
throw new IOException("Can't write file, lock " +
lock.getName() + " exists");
}
lockFile = lock;
}
}
public void close()
throws IOException
{
writer.close();
lockFile.delete();
}
public void write(char[] cbuf, int off, int len)
throws IOException
{
writer.write(cbuf, off, len);
}
public void flush()
throws IOException
{
writer.flush();
}
}
