001/*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements.  See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License.  You may obtain a copy of the License at
008 *
009 *      http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017package org.apache.commons.vfs2;
018
019/**
020 * The fileCache interface. Implementations of this interface are expected to be thread safe.
021 */
022public interface FilesCache {
023
024    /**
025     * Purges the entries corresponding to the FileSystem.
026     *
027     * @param fileSystem The FileSystem.
028     */
029    void clear(FileSystem fileSystem);
030
031    /**
032     * Purges the whole cache.
033     */
034    void close();
035
036    /**
037     * Retrieves a FileObject from the cache by name.
038     *
039     * @param fileSystem The FileSystem.
040     * @param fileName the name
041     * @return the file object or null if file is not cached
042     */
043    FileObject getFile(FileSystem fileSystem, FileName fileName);
044
045    /**
046     * Adds a FileObject to the cache.
047     *
048     * @param file the file
049     */
050    void putFile(FileObject file);
051
052    /**
053     * Adds a FileObject to the cache if it isn't already present.
054     *
055     * @param file the file
056     * @return true if the file was stored, false otherwise.
057     */
058    boolean putFileIfAbsent(FileObject file);
059
060    /**
061     * Removes a file from cache.
062     *
063     * @param fileSystem file system
064     * @param name file name
065     */
066    void removeFile(FileSystem fileSystem, FileName name);
067
068    /*
069      If the cache uses timestamps it could use this method to handle updates of them.
070
071      @param file file name
072     */
073    // public void touchFile(final FileObject file);
074}