/* * Copyright (c) 2004, Oracle and/or its affiliates. All rights reserved. * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. * * This code is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License version 2 only, as * published by the Free Software Foundation.  Oracle designates this * particular file as subject to the "Classpath" exception as provided * by Oracle in the LICENSE file that accompanied this code. * * This code is distributed in the hope that it will be useful, but WITHOUT * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License * version 2 for more details (a copy is included in the LICENSE file that * accompanied this code). * * You should have received a copy of the GNU General Public License version * 2 along with this work; if not, write to the Free Software Foundation, * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. * * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA * or visit www.oracle.com if you need additional information or have any * questions. */ package sun.management; import java.io.File;import java.io.IOException; /* * Utility class to support file system operations * * @since 1.5 */public abstract class FileSystem {     private static final Object lock = new Object();    private static FileSystem fs;     protected FileSystem() { }     /**     * Opens the file system     */    public static FileSystem open() {        synchronized (lock) {            if (fs == null) {                fs = new FileSystemImpl();            }            return fs;        }    }     /**     * Tells whether or not the specified file is located on a     * file system that supports file security or not.     *     * @throws  IOException     if an I/O error occurs.     */    public abstract boolean supportsFileSecurity(File f) throws IOException;     /**     * Tell whether or not the specified file is accessible     * by anything other than the file owner.     *     * @throws  IOException     if an I/O error occurs.     *     * @throws  UnsupportedOperationException     *          If file is located on a file system that doesn't support     *          file security.     */    public abstract boolean isAccessUserOnly(File f) throws IOException;}