/* * Copyright (c) 2007, 2011, 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 java.nio.file.attribute; import static java.nio.file.attribute.PosixFilePermission.*; import java.util.*; /** * This class consists exclusively of static methods that operate on sets of * {@link PosixFilePermission} objects. * * @since 1.7 */ public final class PosixFilePermissions { private PosixFilePermissions() { } // Write string representation of permission bits to {@code sb}. private static void writeBits(StringBuilder sb, boolean r, boolean w, boolean x) { if (r) { sb.append('r'); } else { sb.append('-'); } if (w) { sb.append('w'); } else { sb.append('-'); } if (x) { sb.append('x'); } else { sb.append('-'); } } /** * Returns the {@code String} representation of a set of permissions. It * is guaranteed that the returned {@code String} can be parsed by the * {@link #fromString} method. * *

If the set contains {@code null} or elements that are not of type * {@code PosixFilePermission} then these elements are ignored. * * @param perms * the set of permissions * * @return the string representation of the permission set */ public static String toString(Set perms) { StringBuilder sb = new StringBuilder(9); writeBits(sb, perms.contains(OWNER_READ), perms.contains(OWNER_WRITE), perms.contains(OWNER_EXECUTE)); writeBits(sb, perms.contains(GROUP_READ), perms.contains(GROUP_WRITE), perms.contains(GROUP_EXECUTE)); writeBits(sb, perms.contains(OTHERS_READ), perms.contains(OTHERS_WRITE), perms.contains(OTHERS_EXECUTE)); return sb.toString(); } private static boolean isSet(char c, char setValue) { if (c == setValue) return true; if (c == '-') return false; throw new IllegalArgumentException("Invalid mode"); } private static boolean isR(char c) { return isSet(c, 'r'); } private static boolean isW(char c) { return isSet(c, 'w'); } private static boolean isX(char c) { return isSet(c, 'x'); } /** * Returns the set of permissions corresponding to a given {@code String} * representation. * *

The {@code perms} parameter is a {@code String} representing the * permissions. It has 9 characters that are interpreted as three sets of * three. The first set refers to the owner's permissions; the next to the * group permissions and the last to others. Within each set, the first * character is {@code 'r'} to indicate permission to read, the second * character is {@code 'w'} to indicate permission to write, and the third * character is {@code 'x'} for execute permission. Where a permission is * not set then the corresponding character is set to {@code '-'}. * *

Usage Example: * Suppose we require the set of permissions that indicate the owner has read, * write, and execute permissions, the group has read and execute permissions * and others have none. * 

     *   Set<PosixFilePermission> perms = PosixFilePermissions.fromString("rwxr-x---");
     *
* * @param perms * string representing a set of permissions * * @return the resulting set of permissions * * @throws IllegalArgumentException * if the string cannot be converted to a set of permissions * * @see #toString(Set) */ public static Set fromString(String perms) { if (perms.length() != 9) throw new IllegalArgumentException("Invalid mode"); Set result = EnumSet.noneOf(PosixFilePermission.class); if (isR(perms.charAt(0))) result.add(OWNER_READ); if (isW(perms.charAt(1))) result.add(OWNER_WRITE); if (isX(perms.charAt(2))) result.add(OWNER_EXECUTE); if (isR(perms.charAt(3))) result.add(GROUP_READ); if (isW(perms.charAt(4))) result.add(GROUP_WRITE); if (isX(perms.charAt(5))) result.add(GROUP_EXECUTE); if (isR(perms.charAt(6))) result.add(OTHERS_READ); if (isW(perms.charAt(7))) result.add(OTHERS_WRITE); if (isX(perms.charAt(8))) result.add(OTHERS_EXECUTE); return result; } /** * Creates a {@link FileAttribute}, encapsulating a copy of the given file * permissions, suitable for passing to the {@link java.nio.file.Files#createFile * createFile} or {@link java.nio.file.Files#createDirectory createDirectory} * methods. * * @param perms * the set of permissions * * @return an attribute encapsulating the given file permissions with * {@link FileAttribute#name name} {@code "posix:permissions"} * * @throws ClassCastException * if the set contains elements that are not of type {@code * PosixFilePermission} */ public static FileAttribute> asFileAttribute(Set perms) { // copy set and check for nulls (CCE will be thrown if an element is not // a PosixFilePermission) perms = new HashSet(perms); for (PosixFilePermission p: perms) { if (p == null) throw new NullPointerException(); } final Set value = perms; return new FileAttribute>() { @Override public String name() { return "posix:permissions"; } @Override public Set value() { return Collections.unmodifiableSet(value); } }; } }