/*
* 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.commons.configuration.reloading;
import org.apache.commons.configuration.ex.ConfigurationRuntimeException;
import org.apache.commons.configuration.io.FileHandler;
import org.apache.commons.configuration.io.FileSystem;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.commons.vfs2.FileObject;
import org.apache.commons.vfs2.FileSystemException;
import org.apache.commons.vfs2.FileSystemManager;
import org.apache.commons.vfs2.VFS;
/**
* <p>
* A file-based reloading strategy that uses <a
* href="http://commons.apache.org/vfs/">Commons VFS</a> to determine when a
* file was changed.
* </p>
* <p>
* This reloading strategy is very similar to
* {@link FileHandlerReloadingDetector}, except for the fact that it uses VFS
* and thus can deal with a variety of different configuration sources.
* </p>
* <p>
* This strategy only works with FileConfiguration instances.
* </p>
*
* @author <a
* href="http://commons.apache.org/configuration/team-list.html">Commons
* Configuration team</a>
* @version $Id: VFSFileHandlerReloadingDetector.java 1571738 2014-02-25 16:42:18Z ggregory $
* @since 1.7
*/
public class VFSFileHandlerReloadingDetector extends FileHandlerReloadingDetector
{
/** Stores the logger.*/
private final Log log = LogFactory.getLog(getClass());
/**
* Creates a new instance of {@code VFSFileHandlerReloadingDetector} and
* initializes it with an empty {@code FileHandler} object.
*/
public VFSFileHandlerReloadingDetector()
{
super();
}
/**
* Creates a new instance of {@code VFSFileHandlerReloadingDetector} and
* initializes it with the given {@code FileHandler} object and the given
* refresh delay.
*
* @param handler the {@code FileHandler}
* @param refreshDelay the refresh delay
*/
public VFSFileHandlerReloadingDetector(FileHandler handler,
long refreshDelay)
{
super(handler, refreshDelay);
}
/**
* Creates a new instance of {@code VFSFileHandlerReloadingDetector} and
* initializes it with the given {@code FileHandler} object.
*
* @param handler the {@code FileHandler}
*/
public VFSFileHandlerReloadingDetector(FileHandler handler)
{
super(handler);
}
/**
* {@inheritDoc} This implementation uses Commons VFS to obtain a
* {@code FileObject} and read the date of the last modification.
*/
@Override
protected long getLastModificationDate()
{
FileObject file = getFileObject();
try
{
if (file == null || !file.exists())
{
return 0;
}
return file.getContent().getLastModifiedTime();
}
catch (FileSystemException ex)
{
log.error("Unable to get last modified time for"
+ file.getName().getURI(), ex);
return 0;
}
}
/**
* Returns the file that is monitored by this strategy. Note that the return
* value can be <b>null </b> under some circumstances.
*
* @return the monitored file
*/
protected FileObject getFileObject()
{
if (!getFileHandler().isLocationDefined())
{
return null;
}
try
{
FileSystemManager fsManager = VFS.getManager();
String uri = resolveFileURI();
if (uri == null)
{
throw new ConfigurationRuntimeException("Unable to determine file to monitor");
}
return fsManager.resolveFile(uri);
}
catch (FileSystemException fse)
{
String msg = "Unable to monitor " + getFileHandler().getURL().toString();
log.error(msg);
throw new ConfigurationRuntimeException(msg, fse);
}
}
/**
* Resolves the URI of the monitored file.
*
* @return the URI of the monitored file or <b>null</b> if it cannot be
* resolved
*/
protected String resolveFileURI()
{
FileSystem fs = getFileHandler().getFileSystem();
String uri =
fs.getPath(null, getFileHandler().getURL(), getFileHandler()
.getBasePath(), getFileHandler().getFileName());
return uri;
}
}