/* * 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.provider; import org.apache.commons.vfs.FileName; import org.apache.commons.vfs.FileObject; import org.apache.commons.vfs.FileSystem; import org.apache.commons.vfs.FileSystemException; import org.apache.commons.vfs.FileSystemOptions; /** * A {@link FileProvider} that is layered on top of another, such as the * contents of a zip or tar file. * * @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) $ */ public abstract class AbstractLayeredFileProvider extends AbstractFileProvider implements FileProvider { public AbstractLayeredFileProvider() { super(); setFileNameParser(LayeredFileNameParser.getInstance()); } /** * Locates a file object, by absolute URI. */ public FileObject findFile(final FileObject baseFile, final String uri, final FileSystemOptions properties) throws FileSystemException { // Split the URI up into its parts final LayeredFileName name = (LayeredFileName) parseUri(baseFile!=null?baseFile.getName():null, uri); // Make the URI canonical // Resolve the outer file name final FileName fileName = name.getOuterName(); final FileObject file = getContext().resolveFile(baseFile, fileName.getURI(), properties); // Create the file system final FileObject rootFile = createFileSystem(name.getScheme(), file, properties); // Resolve the file return rootFile.resolveFile(name.getPath()); } /** * Creates a layered file system. */ public synchronized FileObject createFileSystem(final String scheme, final FileObject file, final FileSystemOptions fileSystemOptions) throws FileSystemException { // Check if cached final FileName rootName = file.getName(); FileSystem fs = findFileSystem(rootName, null); if (fs == null) { // Create the file system fs = doCreateFileSystem(scheme, file, fileSystemOptions); addFileSystem(rootName, fs); } return fs.getRoot(); } /** * Creates a layered file system. This method is called if the file system * is not cached. The file system may implement {@link VfsComponent}. * * @param scheme The URI scheme. * @param file The file to create the file system on top of. * @return The file system. */ protected abstract FileSystem doCreateFileSystem(final String scheme, final FileObject file, final FileSystemOptions fileSystemOptions) throws FileSystemException; }