Java tutorial
/* * 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.impl; import java.io.File; import java.util.ArrayList; import java.util.Random; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; import org.apache.commons.vfs2.FileObject; import org.apache.commons.vfs2.FileSelector; import org.apache.commons.vfs2.FileSystemException; import org.apache.commons.vfs2.VfsLog; import org.apache.commons.vfs2.provider.AbstractVfsComponent; import org.apache.commons.vfs2.provider.FileReplicator; import org.apache.commons.vfs2.provider.TemporaryFileStore; import org.apache.commons.vfs2.provider.UriParser; import org.apache.commons.vfs2.util.Messages; /** * A simple file replicator and temporary file store. */ public class DefaultFileReplicator extends AbstractVfsComponent implements FileReplicator, TemporaryFileStore { private static final Log log = LogFactory.getLog(DefaultFileReplicator.class); private static final int MASK = 0xffff; private static final Random random = new Random(); private static final char[] TMP_RESERVED_CHARS = new char[] { '?', '/', '\\', ' ', '&', '"', '\'', '*', '#', ';', ':', '<', '>', '|' }; private final ArrayList<Object> copies = new ArrayList<Object>(); private long filecount; private File tempDir; private boolean tempDirMessageLogged; public DefaultFileReplicator() { } /** * Constructor to set the location of the temporary directory. * * @param tempDir The temporary directory. */ public DefaultFileReplicator(final File tempDir) { this.tempDir = tempDir; } protected void addFile(final Object file) { synchronized (copies) { copies.add(file); } } /** * Allocates a new temporary file. * * @param baseName the base file name. * @return The created File. * @throws FileSystemException if an error occurs. */ @Override public File allocateFile(final String baseName) throws FileSystemException { // Create a unique-ish file name final String basename = createFilename(baseName); synchronized (this) { filecount++; } return createAndAddFile(tempDir, basename); } /** * Closes the replicator, deleting all temporary files. */ @Override public void close() { // Delete the temporary files synchronized (copies) { while (copies.size() > 0) { final File file = (File) removeFile(); deleteFile(file); } } // Clean up the temp directory, if it is empty if (tempDir != null && tempDir.exists() && tempDir.list().length == 0) { tempDir.delete(); tempDir = null; } } protected File createAndAddFile(final File parent, final String basename) throws FileSystemException { final File file = createFile(tempDir, basename); // Keep track to delete later addFile(file); return file; } /** * Create the temporary file. * * @param parent The file to use as the parent of the file being created. * @param name The name of the file to create. * @return The File that was created. * @throws FileSystemException if an error occurs creating the file. */ protected File createFile(final File parent, final String name) throws FileSystemException { return new File(parent, UriParser.decode(name)); } /** * Create the temporary file name. * * @param baseName The base to prepend to the file name being created. * @return the name of the File. */ protected String createFilename(final String baseName) { // BUG29007 // return baseName + "_" + getFilecount() + ".tmp"; // imario@apache.org: BUG34976 get rid of maybe reserved and dangerous characters // e.g. to allow replication of http://hostname.org/fileservlet?file=abc.txt final String safeBasename = UriParser.encode(baseName, TMP_RESERVED_CHARS).replace('%', '_'); return "tmp_" + getFilecount() + "_" + safeBasename; } /** * Physically deletes the file from the filesystem. * * @param file The File to delete. */ protected void deleteFile(final File file) { try { final FileObject fileObject = getContext().toFileObject(file); fileObject.deleteAll(); } catch (final FileSystemException e) { final String message = Messages.getString("vfs.impl/delete-temp.warn", file.getName()); VfsLog.warn(getLogger(), log, message, e); } } protected long getFilecount() { return filecount; } /** * Initializes this component. * * @throws FileSystemException if an error occurs. */ @Override public void init() throws FileSystemException { if (tempDir == null) { final String baseTmpDir = System.getProperty("java.io.tmpdir"); tempDir = new File(baseTmpDir, "vfs_cache").getAbsoluteFile(); } filecount = random.nextInt() & MASK; if (!tempDirMessageLogged) { final String message = Messages.getString("vfs.impl/temp-dir.info", tempDir); VfsLog.info(getLogger(), log, message); tempDirMessageLogged = true; } } /** * Removes a file from the copies list. Will be used for cleanup. * <p> * Notice: The system awaits that the returning object can be cast to a {@link java.io.File}. * * @return the File that was removed. */ protected Object removeFile() { synchronized (copies) { return copies.remove(0); } } /** * Removes a instance from the list of copies. * * @param file The File to remove. */ protected void removeFile(final Object file) { synchronized (copies) { copies.remove(file); } } /** * Creates a local copy of the file, and all its descendants. * * @param srcFile The file to copy. * @param selector The FileSelector. * @return the created File. * @throws FileSystemException if an error occurs copying the file. */ @Override public File replicateFile(final FileObject srcFile, final FileSelector selector) throws FileSystemException { final String basename = srcFile.getName().getBaseName(); final File file = allocateFile(basename); // Copy from the source file final FileObject destFile = getContext().toFileObject(file); destFile.copyFrom(srcFile, selector); return file; } }