| /* |
| * 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.impl; |
| |
| import org.apache.commons.vfs.Capability; |
| import org.apache.commons.vfs.FileName; |
| import org.apache.commons.vfs.FileObject; |
| import org.apache.commons.vfs.FileSystemException; |
| import org.apache.commons.vfs.FileSystemOptions; |
| import org.apache.commons.vfs.NameScope; |
| import org.apache.commons.vfs.provider.AbstractFileSystem; |
| import org.apache.commons.vfs.provider.DelegateFileObject; |
| |
| import java.util.Collection; |
| import java.util.HashMap; |
| import java.util.Iterator; |
| import java.util.Map; |
| |
| /** |
| * A logical file system, made up of set of junctions, or links, to files from |
| * other file systems. |
| * |
| * @author <a href="mailto:adammurdoch@apache.org">Adam Murdoch</a> |
| * @version $Revision$ $Date$ |
| * @todo Handle nested junctions. |
| */ |
| public class VirtualFileSystem |
| extends AbstractFileSystem |
| { |
| private final Map junctions = new HashMap(); |
| |
| public VirtualFileSystem(final FileName rootName, final FileSystemOptions fileSystemOptions) |
| { |
| super(rootName, null, fileSystemOptions); |
| } |
| |
| /** |
| * Adds the capabilities of this file system. |
| */ |
| protected void addCapabilities(final Collection caps) |
| { |
| // TODO - this isn't really true |
| caps.add(Capability.ATTRIBUTES); |
| caps.add(Capability.CREATE); |
| caps.add(Capability.DELETE); |
| caps.add(Capability.GET_TYPE); |
| caps.add(Capability.JUNCTIONS); |
| caps.add(Capability.GET_LAST_MODIFIED); |
| caps.add(Capability.SET_LAST_MODIFIED_FILE); |
| caps.add(Capability.SET_LAST_MODIFIED_FOLDER); |
| caps.add(Capability.LIST_CHILDREN); |
| caps.add(Capability.READ_CONTENT); |
| caps.add(Capability.SIGNING); |
| caps.add(Capability.WRITE_CONTENT); |
| caps.add(Capability.APPEND_CONTENT); |
| } |
| |
| /** |
| * Creates a file object. This method is called only if the requested |
| * file is not cached. |
| */ |
| protected FileObject createFile(final FileName name) |
| throws Exception |
| { |
| // Find the file that the name points to |
| final FileName junctionPoint = getJunctionForFile(name); |
| final FileObject file; |
| if (junctionPoint != null) |
| { |
| // Resolve the real file |
| final FileObject junctionFile = (FileObject) junctions.get(junctionPoint); |
| final String relName = junctionPoint.getRelativeName(name); |
| file = junctionFile.resolveFile(relName, NameScope.DESCENDENT_OR_SELF); |
| } |
| else |
| { |
| file = null; |
| } |
| |
| // Return a wrapper around the file |
| return new DelegateFileObject(name, this, file); |
| } |
| |
| /** |
| * Adds a junction to this file system. |
| */ |
| public void addJunction(final String junctionPoint, |
| final FileObject targetFile) |
| throws FileSystemException |
| { |
| final FileName junctionName = getFileSystemManager().resolveName(getRootName(), junctionPoint); |
| |
| // Check for nested junction - these are not supported yet |
| if (getJunctionForFile(junctionName) != null) |
| { |
| throw new FileSystemException("vfs.impl/nested-junction.error", junctionName); |
| } |
| |
| try |
| { |
| // Add to junction table |
| junctions.put(junctionName, targetFile); |
| |
| // Attach to file |
| final DelegateFileObject junctionFile = (DelegateFileObject) getFileFromCache(junctionName); |
| if (junctionFile != null) |
| { |
| junctionFile.setFile(targetFile); |
| } |
| |
| // Create ancestors of junction point |
| FileName childName = junctionName; |
| boolean done = false; |
| for (FileName parentName = childName.getParent(); |
| !done && parentName != null; |
| childName = parentName, parentName = parentName.getParent()) |
| { |
| DelegateFileObject file = (DelegateFileObject) getFileFromCache(parentName); |
| if (file == null) |
| { |
| file = new DelegateFileObject(parentName, this, null); |
| putFileToCache(file); |
| } |
| else |
| { |
| done = file.exists(); |
| } |
| file.attachChild(childName.getBaseName()); |
| } |
| |
| // TODO - attach all cached children of the junction point to their real file |
| } |
| catch (final Exception e) |
| { |
| throw new FileSystemException("vfs.impl/create-junction.error", junctionName, e); |
| } |
| } |
| |
| /** |
| * Removes a junction from this file system. |
| */ |
| public void removeJunction(final String junctionPoint) |
| throws FileSystemException |
| { |
| final FileName junctionName = getFileSystemManager().resolveName(getRootName(), junctionPoint); |
| junctions.remove(junctionName); |
| |
| // TODO - remove from parents of junction point |
| // TODO - detach all cached children of the junction point from their real file |
| } |
| |
| /** |
| * Locates the junction point for the junction containing the given file. |
| */ |
| private FileName getJunctionForFile(final FileName name) |
| { |
| if (junctions.containsKey(name)) |
| { |
| // The name points to the junction point directly |
| return name; |
| } |
| |
| // Find matching junction |
| for (Iterator iterator = junctions.keySet().iterator(); iterator.hasNext();) |
| { |
| final FileName junctionPoint = (FileName) iterator.next(); |
| if (junctionPoint.isDescendent(name)) |
| { |
| return junctionPoint; |
| } |
| } |
| |
| // None |
| return null; |
| } |
| } |