jdk/src/share/classes/java/nio/file/attribute/PosixFilePermissions.java
changeset 2057 3acf8e5e2ca0
child 2072 80dfe4469bbd
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/jdk/src/share/classes/java/nio/file/attribute/PosixFilePermissions.java	Sun Feb 15 12:25:54 2009 +0000
@@ -0,0 +1,180 @@
+/*
+ * Copyright 2007-2009 Sun Microsystems, Inc.  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.  Sun designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Sun 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
+ * CA 95054 USA or visit www.sun.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 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.
+     *
+     * <p> 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
+     *
+     * @see #fromString
+     */
+    public static String toString(Set<PosixFilePermission> 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.
+     *
+     * <p> 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 '-'}.
+     *
+     * <p> <b>Usage Example:</b>
+     * 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.
+     * <pre>
+     *   Set&lt;PosixFilePermission&gt; perms = PosixFilePermissions.fromString("rwxr-x---");
+     * </pre>
+     *
+     * @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<PosixFilePermission> fromString(String perms) {
+        if (perms.length() != 9)
+            throw new IllegalArgumentException("Invalid mode");
+        Set<PosixFilePermission> result = new HashSet<PosixFilePermission>();
+        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.Path#createFile
+     * createFile} or {@link java.nio.file.Path#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 sets contains elements that are not of type {@code
+     *          PosixFilePermission}
+     */
+    public static FileAttribute<Set<PosixFilePermission>>
+        asFileAttribute(Set<PosixFilePermission> perms)
+    {
+        // copy set and check for nulls (CCE will be thrown if an element is not
+        // a PosixFilePermission)
+        perms = new HashSet<PosixFilePermission>(perms);
+        for (PosixFilePermission p: perms) {
+            if (p == null)
+                throw new NullPointerException();
+        }
+        final Set<PosixFilePermission> value = perms;
+        return new FileAttribute<Set<PosixFilePermission>>() {
+            @Override
+            public String name() {
+                return "posix:permissions";
+            }
+            @Override
+            public Set<PosixFilePermission> value() {
+                return Collections.unmodifiableSet(value);
+            }
+        };
+    }
+}