/* * 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.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.FileType; 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: 480428 $ $Date: 2006-11-29 07:15:24 +0100 (Mi, 29 Nov 2006) $ * @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(); } // As this is the parent of our junction it has to be a folder file.attachChild(childName, FileType.FOLDER); } // 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; } }