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 java.lang.ref.Reference;
020import java.lang.ref.ReferenceQueue;
021import java.lang.ref.WeakReference;
022
023import org.apache.commons.vfs2.FileObject;
024
025/**
026 * This implementation caches every file as long as it is strongly reachable by the Java vm. As soon as the object is no
027 * longer reachable it will be discarded. In contrast to the SoftRefFilesCache this implementation might free resources
028 * faster as it doesn't wait until a memory limitation.
029 *
030 * @see java.lang.ref.WeakReference
031 */
032public class WeakRefFilesCache extends SoftRefFilesCache {
033
034    /**
035     * Constructs a new instance.
036     */
037    public WeakRefFilesCache() {
038        // empty
039    }
040
041    @Override
042    protected Reference<FileObject> createReference(final FileObject file, final ReferenceQueue<FileObject> refqueue) {
043        return new WeakReference<>(file, refqueue);
044    }
045}