1 /*

     2  * Copyright 2007-2009 Sun Microsystems, Inc.  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.  Sun designates this

     8  * particular file as subject to the "Classpath" exception as provided

     9  * by Sun 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,

    22  * CA 95054 USA or visit www.sun.com if you need additional information or

    23  * have any questions.

    24  */

    25 

    26 package java.nio.file;

    27 

    28 /**

    29  * Defines the standard open options.

    30  *

    31  * @since 1.7

    32  */

    33 

    34 public enum StandardOpenOption implements OpenOption {

    35     /**

    36      * Open for read access.

    37      */

    38     READ,

    39 

    40     /**

    41      * Open for write access.

    42      */

    43     WRITE,

    44 

    45     /**

    46      * If the file is opened for {@link #WRITE} access then bytes will be written

    47      * to the end of the file rather than the beginning.

    48      *

    49      * <p> If the file is opened for write access by other programs, then it

    50      * is file system specific if writing to the end of the file is atomic.

    51      */

    52     APPEND,

    53 

    54     /**

    55      * If the file already exists and it is opened for {@link #WRITE}

    56      * access, then its length is truncated to 0. This option is ignored

    57      * if the file is opened only for {@link #READ} access.

    58      */

    59     TRUNCATE_EXISTING,

    60 

    61     /**

    62      * Create a new file if it does not exist.

    63      * This option is ignored if the {@link #CREATE_NEW} option is also set.

    64      * The check for the existence of the file and the creation of the file

    65      * if it does not exist is atomic with respect to other file system

    66      * operations.

    67      */

    68     CREATE,

    69 

    70     /**

    71      * Create a new file, failing if the file already exists.

    72      * The check for the existence of the file and the creation of the file

    73      * if it does not exist is atomic with respect to other file system

    74      * operations.

    75      */

    76     CREATE_NEW,

    77 

    78     /**

    79      * Delete on close. When this option is present then the implementation

    80      * makes a <em>best effort</em> attempt to delete the file when closed

    81      * by the appropriate {@code close} method. If the {@code close} method is

    82      * not invoked then a <em>best effort</em> attempt is made to delete the

    83      * file when the Java virtual machine terminates (either normally, as

    84      * defined by the Java Language Specification, or where possible, abnormally).

    85      * This option is primarily intended for use with <em>work files</em> that

    86      * are used solely by a single instance of the Java virtual machine. This

    87      * option is not recommended for use when opening files that are open

    88      * concurrently by other entities. Many of the details as to when and how

    89      * the file is deleted are implementation specific and therefore not

    90      * specified. In particular, an implementation may be unable to guarantee

    91      * that it deletes the expected file when replaced by an attacker while the

    92      * file is open. Consequently, security sensitive applications should take

    93      * care when using this option.

    94      *

    95      * <p> For security reasons, this option may imply the {@link

    96      * LinkOption#NOFOLLOW_LINKS} option. In other words, if the option is present

    97      * when opening an existing file that is a symbolic link then it may fail

    98      * (by throwing {@link java.io.IOException}).

    99      */

   100     DELETE_ON_CLOSE,

   101 

   102     /**

   103      * Sparse file. When used with the {@link #CREATE_NEW} option then this

   104      * option provides a <em>hint</em> that the new file will be sparse. The

   105      * option is ignored when the file system does not support the creation of

   106      * sparse files.

   107      */

   108     SPARSE,

   109 

   110     /**

   111      * Requires that every update to the file's content or metadata be written

   112      * synchronously to the underlying storage device.

   113      *

   114      * @see <a href="package-summary.html#integrity">Synchronized I/O file integrity</a>

   115      */

   116     SYNC,

   117 

   118     /**

   119      * Requires that every update to the file's content be written

   120      * synchronously to the underlying storage device.

   121      *

   122      * @see <a href="package-summary.html#integrity">Synchronized I/O file integrity</a>

   123      */

   124     DSYNC;

   125 }