/*
* Copyright 2002-2005 The Apache Software Foundation.
*
* Licensed 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.vfs.provider;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.commons.vfs.Capability;
import org.apache.commons.vfs.FileListener;
import org.apache.commons.vfs.FileName;
import org.apache.commons.vfs.FileObject;
import org.apache.commons.vfs.FileSelector;
import org.apache.commons.vfs.FileSystem;
import org.apache.commons.vfs.FileSystemException;
import org.apache.commons.vfs.FileSystemManager;
import org.apache.commons.vfs.FileSystemOptions;
import org.apache.commons.vfs.FilesCache;
import org.apache.commons.vfs.VfsLog;
import org.apache.commons.vfs.events.AbstractFileChangeEvent;
import org.apache.commons.vfs.events.ChangedEvent;
import org.apache.commons.vfs.events.CreateEvent;
import org.apache.commons.vfs.events.DeleteEventAbstractFile;
import org.apache.commons.vfs.util.Messages;
import java.io.File;
import java.util.ArrayList;
import java.util.Collection;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Map;
/**
* A partial {@link org.apache.commons.vfs.FileSystem} implementation.
*
* @author <a href="mailto:adammurdoch@apache.org">Adam Murdoch</a>
*/
public abstract class AbstractFileSystem
extends AbstractVfsComponent
implements FileSystem
{
private final static Log log = LogFactory.getLog(AbstractFileSystem.class);
private final FileName rootName;
private FileObject parentLayer;
// private FileObject root;
private final Collection caps = new HashSet();
/**
* Map from FileName to FileObject.
*/
// private FilesCache files;
/**
* Map from FileName to an ArrayList of listeners for that file.
*/
private final Map listenerMap = new HashMap();
/**
* FileSystemOptions used for configuration
*/
private final FileSystemOptions fileSystemOptions;
/**
* How many files are activley using the filesystem
*/
private long useCount;
private FileSystemKey cacheKey;
/**
* open streams counter for this filesystem
*/
private int openStreams;
protected AbstractFileSystem(final FileName rootName,
final FileObject parentLayer,
final FileSystemOptions fileSystemOptions)
{
// this.parentLayer = parentLayer;
this.parentLayer = parentLayer;
this.rootName = rootName;
this.fileSystemOptions = fileSystemOptions;
// this.files = null;
}
/**
* Initialises this component.
*/
public void init() throws FileSystemException
{
addCapabilities(caps);
}
/**
* Closes this component.
*/
public void close()
{
closeCommunicationLink();
parentLayer = null;
}
/**
* Close the underlaying link used to access the files
*/
public void closeCommunicationLink()
{
synchronized (this)
{
doCloseCommunicationLink();
}
}
/**
* Close the underlaying link used to access the files
*/
protected void doCloseCommunicationLink()
{
}
/**
* Creates a file object. This method is called only if the requested
* file is not cached.
*/
protected abstract FileObject createFile(final FileName name)
throws Exception;
/**
* Adds the capabilities of this file system.
*/
protected abstract void addCapabilities(Collection caps);
/**
* Returns the name of the root of this file system.
*/
public FileName getRootName()
{
return rootName;
}
/**
* Adds a file object to the cache.
*/
protected void putFileToCache(final FileObject file)
{
getCache().putFile(file);
// files.put(file.getName(), file);
}
private FilesCache getCache()
{
FilesCache files;
//if (this.files == null)
{
files = getContext().getFileSystemManager().getFilesCache();
if (files == null)
{
throw new RuntimeException(Messages.getString("vfs.provider/files-cache-missing.error"));
}
}
return files;
}
/**
* Returns a cached file.
*/
protected FileObject getFileFromCache(final FileName name)
{
return getCache().getFile(this, name);
// return (FileObject) files.get(name);
}
/**
* remove a cached file.
*/
protected void removeFileFromCache(final FileName name)
{
getCache().removeFile(this, name);
}
/**
* Determines if this file system has a particular capability.
*/
public boolean hasCapability(final Capability capability)
{
return caps.contains(capability);
}
/**
* Retrieves the attribute with the specified name. The default
* implementation simply throws an exception.
*/
public Object getAttribute(final String attrName) throws FileSystemException
{
throw new FileSystemException("vfs.provider/get-attribute-not-supported.error");
}
/**
* Sets the attribute with the specified name. The default
* implementation simply throws an exception.
*/
public void setAttribute(final String attrName, final Object value)
throws FileSystemException
{
throw new FileSystemException("vfs.provider/set-attribute-not-supported.error");
}
/**
* Returns the parent layer if this is a layered file system.
*/
public FileObject getParentLayer() throws FileSystemException
{
return parentLayer;
}
/**
* Returns the root file of this file system.
*/
public FileObject getRoot() throws FileSystemException
{
return resolveFile(rootName);
/*
if (root == null)
{
root = resolveFile(rootName);
}
return root;
*/
}
/**
* Finds a file in this file system.
*/
public FileObject resolveFile(final String nameStr) throws FileSystemException
{
// Resolve the name, and create the file
final FileName name = getFileSystemManager().resolveName(rootName, nameStr);
return resolveFile(name);
}
/**
* Finds a file in this file system.
*/
public synchronized FileObject resolveFile(final FileName name) throws FileSystemException
{
return resolveFile(name, true);
}
private synchronized FileObject resolveFile(final FileName name, final boolean useCache) throws FileSystemException
{
if (!rootName.getRootURI().equals(name.getRootURI()))
{
throw new FileSystemException("vfs.provider/mismatched-fs-for-name.error",
new Object[]{
name, rootName, name.getRootURI()});
}
// imario@apache.org ==> use getFileFromCache
FileObject file;
if (useCache)
{
file = getFileFromCache(name);
}
else
{
file = null;
}
// FileObject file = (FileObject) files.get(name);
if (file == null)
{
try
{
synchronized (this)
{
file = createFile(name);
}
}
catch (Exception e)
{
throw new FileSystemException("vfs.provider/resolve-file.error", name, e);
}
// imario@apache.org ==> use putFileToCache
if (useCache)
{
putFileToCache(file);
}
// files.put(name, file);
}
return file;
}
/**
* Creates a temporary local copy of a file and its descendents.
*/
public File replicateFile(final FileObject file,
final FileSelector selector)
throws FileSystemException
{
if (!file.exists())
{
throw new FileSystemException("vfs.provider/replicate-missing-file.error", file.getName());
}
try
{
return doReplicateFile(file, selector);
}
catch (final Exception e)
{
throw new FileSystemException("vfs.provider/replicate-file.error", file.getName(), e);
}
}
/**
* Return the FileSystemOptions used to instantiate this filesystem
*/
public FileSystemOptions getFileSystemOptions()
{
return fileSystemOptions;
}
/**
* Return the FileSystemManager used to instantiate this filesystem
*/
public FileSystemManager getFileSystemManager()
{
return getContext().getFileSystemManager();
// return manager;
}
/**
* Returns the accuracy of the last modification time
*
* @return ms 0 perfectly accurate, >0 might be off by this value e.g. sftp 1000ms
*/
public double getLastModTimeAccuracy()
{
return 0;
}
/**
* Creates a temporary local copy of a file and its descendents.
*/
protected File doReplicateFile(final FileObject file,
final FileSelector selector)
throws Exception
{
return getContext().getReplicator().replicateFile(file, selector);
}
/**
* Adds a junction to this file system.
*/
public void addJunction(final String junctionPoint,
final FileObject targetFile)
throws FileSystemException
{
throw new FileSystemException("vfs.provider/junctions-not-supported.error", rootName);
}
/**
* Removes a junction from this file system.
*/
public void removeJunction(final String junctionPoint) throws FileSystemException
{
throw new FileSystemException("vfs.provider/junctions-not-supported.error", rootName);
}
/**
* Adds a listener on a file in this file system.
*/
public void addListener(final FileObject file,
final FileListener listener)
{
synchronized (listenerMap)
{
ArrayList listeners = (ArrayList) listenerMap.get(file.getName());
if (listeners == null)
{
listeners = new ArrayList();
listenerMap.put(file.getName(), listeners);
}
listeners.add(listener);
}
}
/**
* Removes a listener from a file in this file system.
*/
public void removeListener(final FileObject file,
final FileListener listener)
{
synchronized (listenerMap)
{
final ArrayList listeners = (ArrayList) listenerMap.get(file.getName());
if (listeners != null)
{
listeners.remove(listener);
}
}
}
/**
* Fires a file create event.
*/
public void fireFileCreated(final FileObject file)
{
fireEvent(new CreateEvent(file));
}
/**
* Fires a file delete event.
*/
public void fireFileDeleted(final FileObject file)
{
fireEvent(new DeleteEventAbstractFile(file));
}
/**
* Fires a file changed event. <br />
* This will only happen if you monitor the file using {@link org.apache.commons.vfs.FileMonitor}.
*/
public void fireFileChanged(final FileObject file)
{
fireEvent(new ChangedEvent(file));
}
/**
* returns true if no file is using this filesystem
*/
public boolean isReleaseable()
{
return useCount < 1;
}
void freeResources()
{
}
/**
* Fires an event.
*/
private void fireEvent(final AbstractFileChangeEvent event)
{
synchronized (listenerMap)
{
final FileObject file = event.getFile();
final ArrayList listeners = (ArrayList) listenerMap.get(file.getName());
if (listeners != null)
{
final int count = listeners.size();
for (int i = 0; i < count; i++)
{
final FileListener listener = (FileListener) listeners.get(i);
try
{
event.notify(listener);
}
catch (final Exception e)
{
final String message = Messages.getString("vfs.provider/notify-listener.warn", file);
// getLogger().warn(message, e);
VfsLog.warn(getLogger(), log, message, e);
}
}
}
}
}
void fileDetached(FileObject fileObject)
{
useCount--;
}
void fileAttached(FileObject fileObject)
{
useCount++;
}
void setCacheKey(FileSystemKey cacheKey)
{
this.cacheKey = cacheKey;
}
FileSystemKey getCacheKey()
{
return this.cacheKey;
}
void streamOpened()
{
synchronized (this)
{
openStreams++;
}
}
void streamClosed()
{
synchronized (this)
{
if (openStreams > 0)
{
openStreams--;
if (openStreams < 1)
{
notifyAllStreamsClosed();
}
}
}
}
/**
* will be called after all file-objects closed their streams.
*/
protected void notifyAllStreamsClosed()
{
}
/**
* check if this filesystem has open streams
*/
public boolean isOpen()
{
synchronized (this)
{
return openStreams > 0;
}
}
}