/*
 * 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;

/**
 * The fileCache interface. Implementations of this interface are expected to be thread safe.
 */
public interface FilesCache {

    /**
     * Purges the entries corresponding to the FileSystem.
     *
     * @param fileSystem The FileSystem.
     */
    void clear(final FileSystem fileSystem);

    /**
     * Purges the whole cache.
     */
    void close();

    /**
     * Retrieves a FileObject from the cache by name.
     *
     * @param fileSystem The FileSystem.
     * @param fileName the name
     * @return the file object or null if file is not cached
     */
    FileObject getFile(final FileSystem fileSystem, final FileName fileName);

    /**
     * Adds a FileObject to the cache.
     *
     * @param file the file
     */
    void putFile(final FileObject file);

    /**
     * Adds a FileObject to the cache if it isn't already present.
     *
     * @param file the file
     * @return true if the file was stored, false otherwise.
     */
    boolean putFileIfAbsent(final FileObject file);

    /**
     * Removes a file from cache.
     *
     * @param fileSystem file system
     * @param name file name
     */
    void removeFile(final FileSystem fileSystem, final FileName name);

    /*
      If the cache uses timestamps it could use this method to handle updates of them.

      @param file file name
     */
    // public void touchFile(final FileObject file);
}