1 /* 2 * Copyright (c) 2007, 2018, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. Oracle designates this 8 * particular file as subject to the "Classpath" exception as provided 9 * by Oracle in the LICENSE file that accompanied this code. 10 * 11 * This code is distributed in the hope that it will be useful, but WITHOUT 12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 14 * version 2 for more details (a copy is included in the LICENSE file that 15 * accompanied this code). 16 * 17 * You should have received a copy of the GNU General Public License version 18 * 2 along with this work; if not, write to the Free Software Foundation, 19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 20 * 21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 22 * or visit www.oracle.com if you need additional information or have any 23 * questions. 24 */ 25 26 package com.sun.nio.file; 27 28 import java.nio.file.OpenOption; 29 import jdk.internal.misc.FileSystemOption; 30 31 /** 32 * Defines <em>extended</em> open options supported on some platforms 33 * by Sun's provider implementation. 34 * 35 * @since 1.7 36 */ 37 38 public enum ExtendedOpenOption implements OpenOption { 39 /** 40 * Prevent operations on the file that request read access. 41 */ 42 NOSHARE_READ(FileSystemOption.NOSHARE_READ), 43 /** 44 * Prevent operations on the file that request write access. 45 */ 46 NOSHARE_WRITE(FileSystemOption.NOSHARE_WRITE), 47 /** 48 * Prevent operations on the file that request delete access. 49 */ 50 NOSHARE_DELETE(FileSystemOption.NOSHARE_DELETE), 51 52 /** 53 * Requires that direct I/O be used for read or write access. 54 * Attempting to open a file with this option set will result in 55 * an {@code UnsupportedOperationException} if the operating system or 56 * file system does not support Direct I/O or a sufficient equivalent. 57 * 58 * @apiNote 59 * The DIRECT option enables performing file I/O directly between user 60 * buffers and the file thereby circumventing the operating system page 61 * cache and possibly avoiding the thrashing which could otherwise occur 62 * in I/O-intensive applications. This option may be of benefit to 63 * applications which do their own caching or do random I/O operations 64 * on large data sets. It is likely to provide the most benefit when 65 * the file is stored on a device which has high I/O throughput capacity. 66 * The option should be used with caution however as in general it is 67 * likely to degrade performance. The performance effects of using it 68 * should be evaluated in each particular circumstance. 69 * 70 * @since 10 71 */ 72 DIRECT(FileSystemOption.DIRECT); 73 ExtendedOpenOption(FileSystemOption<Void> option)74 ExtendedOpenOption(FileSystemOption<Void> option) { 75 option.register(this); 76 } 77 } 78