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.cache;
018
019import org.apache.commons.vfs2.FileName;
020import org.apache.commons.vfs2.FileObject;
021import org.apache.commons.vfs2.FileSystem;
022
023/**
024 * A {@link org.apache.commons.vfs2.FilesCache} implementation.
025 * <p>
026 * This implementation never ever caches a single file.
027 * </p>
028 * <p>
029 * <strong>Notice</strong>: if you use resolveFile(uri) multiple times with the same path, the system will always create a new
030 * instance. Changes on one instance of this file are not seen by the others.
031 * </p>
032 */
033public class NullFilesCache extends AbstractFilesCache {
034
035    /**
036     * Constructs a new instance.
037     */
038    public NullFilesCache() {
039        // empty
040    }
041
042    @Override
043    public void clear(final FileSystem filesystem) {
044        // empty
045    }
046
047    @Override
048    public FileObject getFile(final FileSystem filesystem, final FileName name) {
049        return null;
050    }
051
052    @Override
053    public void putFile(final FileObject file) {
054        // empty
055    }
056
057    @Override
058    public boolean putFileIfAbsent(final FileObject file) {
059        return false;
060    }
061
062    @Override
063    public void removeFile(final FileSystem filesystem, final FileName name) {
064        // empty
065    }
066}