org.spearce.jgit/src/org/spearce/jgit/util/FS.java

   1 /*
   2  *  Copyright (C) 2008  Shawn Pearce <spearce@spearce.org>
   3  *
   4  *  This library is free software; you can redistribute it and/or
   5  *  modify it under the terms of the GNU General Public
   6  *  License, version 2, as published by the Free Software Foundation.
   7  *
   8  *  This library is distributed in the hope that it will be useful,
   9  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  11  *  General Public License for more details.
  12  *
  13  *  You should have received a copy of the GNU General Public
  14  *  License along with this library; if not, write to the Free Software
  15  *  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301
  16  */
  17 package org.spearce.jgit.util;
  18
  19 import java.io.File;
  20
  21 /** Abstraction to support various file system operations not in Java. */
  22 public abstract class FS {
  23         /** The implementation selected for this operating system and JRE. */
  24         public static final FS INSTANCE;
  25
  26         static {
  27                 if (FS_Win32.detect())
  28                         INSTANCE = new FS_Win32();
  29                 else if (FS_POSIX_Java6.detect())
  30                         INSTANCE = new FS_POSIX_Java6();
  31                 else
  32                         INSTANCE = new FS_POSIX_Java5();
  33         }
  34
  35         /**
  36          * Does this operating system and JRE support the execute flag on files?
  37          *
  38          * @return true if this implementation can provide reasonably accurate
  39          *         executable bit information; false otherwise.
  40          */
  41         public abstract boolean supportsExecute();
  42
  43         /**
  44          * Determine if the file is executable (or not).
  45          * <p>
  46          * Not all platforms and JREs support executable flags on files. If the
  47          * feature is unsupported this method will always return false.
  48          *
  49          * @param f
  50          *            abstract path to test.
  51          * @return true if the file is believed to be executable by the user.
  52          */
  53         public abstract boolean canExecute(File f);
  54
  55         /**
  56          * Set a file to be executable by the user.
  57          * <p>
  58          * Not all platforms and JREs support executable flags on files. If the
  59          * feature is unsupported this method will always return false and no
  60          * changes will be made to the file specified.
  61          *
  62          * @param f
  63          *            path to modify the executable status of.
  64          * @param canExec
  65          *            true to enable execution; false to disable it.
  66          * @return true if the change succeeded; false otherwise.
  67          */
  68         public abstract boolean setExecute(File f, boolean canExec);
  69 }