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Apache Commons VFS is a Virtual File System library.
/*
* 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.vfs2.provider;
import java.io.InputStream;
import java.io.OutputStream;
import java.security.cert.Certificate;
import java.util.HashSet;
import java.util.Map;
import java.util.Set;
import org.apache.commons.vfs2.FileChangeEvent;
import org.apache.commons.vfs2.FileContentInfo;
import org.apache.commons.vfs2.FileListener;
import org.apache.commons.vfs2.FileName;
import org.apache.commons.vfs2.FileNotFolderException;
import org.apache.commons.vfs2.FileObject;
import org.apache.commons.vfs2.FileSystemException;
import org.apache.commons.vfs2.FileType;
import org.apache.commons.vfs2.RandomAccessContent;
import org.apache.commons.vfs2.util.RandomAccessMode;
import org.apache.commons.vfs2.util.WeakRefFileListener;
/**
* A file backed by another file.
*
* TODO - Extract subclass that overlays the children.
*
*
* @param A subclass of AbstractFileSystem.
*/
public class DelegateFileObject extends AbstractFileObject
implements FileListener {
private FileObject file;
private final Set children = new HashSet<>();
private boolean ignoreEvent;
public DelegateFileObject(final AbstractFileName name, final AFS fileSystem, final FileObject file)
throws FileSystemException {
super(name, fileSystem);
this.file = file;
if (file != null) {
WeakRefFileListener.installListener(file, this);
}
}
/**
* Get access to the delegated file.
*
* @return The FileObject.
* @since 2.0
*/
public FileObject getDelegateFile() {
return file;
}
/**
* Adds a child to this file.
*
* @param baseName The base FileName.
* @param type The FileType.
* @throws Exception if an error occurs.
*/
public void attachChild(final FileName baseName, final FileType type) throws Exception {
final FileType oldType = doGetType();
if (children.add(baseName.getBaseName())) {
childrenChanged(baseName, type);
}
maybeTypeChanged(oldType);
}
/**
* Attaches or detaches the target file.
*
* @param file The FileObject.
* @throws Exception if an error occurs.
*/
public void setFile(final FileObject file) throws Exception {
final FileType oldType = doGetType();
if (file != null) {
WeakRefFileListener.installListener(file, this);
}
this.file = file;
maybeTypeChanged(oldType);
}
/**
* Checks whether the file's type has changed, and fires the appropriate events.
*
* @param oldType The old FileType.
* @throws Exception if an error occurs.
*/
private void maybeTypeChanged(final FileType oldType) throws Exception {
final FileType newType = doGetType();
if (oldType == FileType.IMAGINARY && newType != FileType.IMAGINARY) {
handleCreate(newType);
} else if (oldType != FileType.IMAGINARY && newType == FileType.IMAGINARY) {
handleDelete();
}
}
/**
* Determines the type of the file, returns null if the file does not exist.
*/
@Override
protected FileType doGetType() throws FileSystemException {
if (file != null) {
return file.getType();
} else if (children.size() > 0) {
return FileType.FOLDER;
} else {
return FileType.IMAGINARY;
}
}
/**
* Determines if this file can be read.
*/
@Override
protected boolean doIsReadable() throws FileSystemException {
if (file != null) {
return file.isReadable();
}
return true;
}
/**
* Determines if this file can be written to.
*/
@Override
protected boolean doIsWriteable() throws FileSystemException {
if (file != null) {
return file.isWriteable();
}
return false;
}
/**
* Determines if this file is executable.
*/
@Override
protected boolean doIsExecutable() throws FileSystemException {
if (file != null) {
return file.isExecutable();
}
return false;
}
/**
* Determines if this file is hidden.
*/
@Override
protected boolean doIsHidden() throws FileSystemException {
if (file != null) {
return file.isHidden();
}
return false;
}
/**
* Lists the children of the file.
*/
@Override
protected String[] doListChildren() throws Exception {
if (file != null) {
final FileObject[] children;
try {
children = file.getChildren();
}
// VFS-210
catch (final FileNotFolderException e) {
throw new FileNotFolderException(getName(), e);
}
final String[] childNames = new String[children.length];
for (int i = 0; i < children.length; i++) {
childNames[i] = children[i].getName().getBaseName();
}
return childNames;
}
return children.toArray(new String[children.size()]);
}
/**
* Creates this file as a folder.
*/
@Override
protected void doCreateFolder() throws Exception {
ignoreEvent = true;
try {
file.createFolder();
} finally {
ignoreEvent = false;
}
}
/**
* Deletes the file.
*/
@Override
protected void doDelete() throws Exception {
ignoreEvent = true;
try {
file.delete();
} finally {
ignoreEvent = false;
}
}
/**
* Returns the size of the file content (in bytes). Is only called if {@link #doGetType} returns
* {@link FileType#FILE}.
*/
@Override
protected long doGetContentSize() throws Exception {
return file.getContent().getSize();
}
/**
* Returns the attributes of this file.
*/
@Override
protected Map doGetAttributes() throws Exception {
return file.getContent().getAttributes();
}
/**
* Sets an attribute of this file.
*/
@Override
protected void doSetAttribute(final String atttrName, final Object value) throws Exception {
file.getContent().setAttribute(atttrName, value);
}
/**
* Returns the certificates of this file.
*/
@Override
protected Certificate[] doGetCertificates() throws Exception {
return file.getContent().getCertificates();
}
/**
* Returns the last-modified time of this file.
*/
@Override
protected long doGetLastModifiedTime() throws Exception {
return file.getContent().getLastModifiedTime();
}
/**
* Sets the last-modified time of this file.
*
* @since 2.0
*/
@Override
protected boolean doSetLastModifiedTime(final long modtime) throws Exception {
file.getContent().setLastModifiedTime(modtime);
return true;
}
/**
* Creates an input stream to read the file content from.
*/
@Override
protected InputStream doGetInputStream(final int bufferSize) throws Exception {
return file.getContent().getInputStream(bufferSize);
}
/**
* Creates an output stream to write the file content to.
*/
@Override
protected OutputStream doGetOutputStream(final boolean bAppend) throws Exception {
return file.getContent().getOutputStream(bAppend);
}
/**
* Called when a file is created.
*
* @param event The FileChangeEvent.
* @throws Exception if an error occurs.
*/
@Override
public void fileCreated(final FileChangeEvent event) throws Exception {
if (event.getFileObject() != file) {
return;
}
if (!ignoreEvent) {
handleCreate(file.getType());
}
}
/**
* Called when a file is deleted.
*
* @param event The FileChangeEvent.
* @throws Exception if an error occurs.
*/
@Override
public void fileDeleted(final FileChangeEvent event) throws Exception {
if (event.getFileObject() != file) {
return;
}
if (!ignoreEvent) {
handleDelete();
}
}
/**
* Called when a file is changed.
*
* This will only happen if you monitor the file using {@link org.apache.commons.vfs2.FileMonitor}.
*
*
* @param event The FileChangeEvent.
* @throws Exception if an error occurs.
*/
@Override
public void fileChanged(final FileChangeEvent event) throws Exception {
if (event.getFileObject() != file) {
return;
}
if (!ignoreEvent) {
handleChanged();
}
}
/**
* Close the delegated file.
*
* @throws FileSystemException if an error occurs.
*/
@Override
public void close() throws FileSystemException {
super.close();
if (file != null) {
file.close();
}
}
/**
* Refresh file information.
*
* @throws FileSystemException if an error occurs.
* @since 2.0
*/
@Override
public void refresh() throws FileSystemException {
super.refresh();
if (file != null) {
file.refresh();
}
}
/**
* Return file content info.
*
* @return the file content info of the delegee.
* @throws Exception Any thrown Exception is wrapped in FileSystemException.
* @since 2.0
*/
protected FileContentInfo doGetContentInfo() throws Exception {
return file.getContent().getContentInfo();
}
/**
* Renames the file.
*
* @param newFile the new location/name.
* @throws Exception Any thrown Exception is wrapped in FileSystemException.
* @since 2.0
*/
@Override
protected void doRename(final FileObject newFile) throws Exception {
file.moveTo(((DelegateFileObject) newFile).file);
}
/**
* Removes an attribute of this file.
*
* @since 2.0
*/
@Override
protected void doRemoveAttribute(final String atttrName) throws Exception {
file.getContent().removeAttribute(atttrName);
}
/**
* Creates access to the file for random i/o.
*
* @since 2.0
*/
@Override
protected RandomAccessContent doGetRandomAccessContent(final RandomAccessMode mode) throws Exception {
return file.getContent().getRandomAccessContent(mode);
}
}