jdk/src/share/classes/java/nio/file/attribute/AclEntry.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/AclEntry.java	Sun Feb 15 12:25:54 2009 +0000
@@ -0,0 +1,394 @@
+/*
+ * 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 java.util.*;
+
+/**
+ * An entry in an access control list (ACL).
+ *
+ * <p> The ACL entry represented by this class is based on the ACL model
+ * specified in <a href="http://www.ietf.org/rfc/rfc3530.txt"><i>RFC&nbsp;3530:
+ * Network File System (NFS) version 4 Protocol</i></a>. Each entry has four
+ * components as follows:
+ *
+ * <ol>
+ *    <li><p> The {@link #type() type} component determines if the entry
+ *    grants or denies access. </p></li>
+ *
+ *    <li><p> The {@link #principal() principal} component, sometimes called the
+ *    "who" component, is a {@link UserPrincipal} corresponding to the identity
+ *    that the entry grants or denies access
+ *    </p></li>
+ *
+ *    <li><p> The {@link #permissions permissions} component is a set of
+ *    {@link AclEntryPermission permissions}
+ *    </p></li>
+ *
+ *    <li><p> The {@link #flags flags} component is a set of {@link AclEntryFlag
+ *    flags} to indicate how entries are inherited and propagated </p></li>
+ * </ol>
+ *
+ * <p> ACL entries are created using an associated {@link Builder} object by
+ * invoking its {@link Builder#build build} method.
+ *
+ * <p> ACL entries are immutable and are safe for use by multiple concurrent
+ * threads.
+ *
+ * @since 1.7
+ */
+
+public final class AclEntry {
+
+    private final AclEntryType type;
+    private final UserPrincipal who;
+    private final Set<AclEntryPermission> perms;
+    private final Set<AclEntryFlag> flags;
+
+    // cached hash code
+    private volatile int hash;
+
+    // private constructor
+    private AclEntry(AclEntryType type,
+                     UserPrincipal who,
+                     Set<AclEntryPermission> perms,
+                     Set<AclEntryFlag> flags)
+    {
+        this.type = type;
+        this.who = who;
+        this.perms = perms;
+        this.flags = flags;
+    }
+
+    /**
+     * A builder of {@link AclEntry} objects.
+     *
+     * <p> A {@code Builder} object is obtained by invoking one of the {@link
+     * AclEntry#newBuilder newBuilder} methods defined by the {@code AclEntry}
+     * class.
+     *
+     * <p> Builder objects are mutable and are not safe for use by multiple
+     * concurrent threads without appropriate synchronization.
+     *
+     * @since 1.7
+     */
+    public static final class Builder {
+        private AclEntryType type;
+        private UserPrincipal who;
+        private Set<AclEntryPermission> perms;
+        private Set<AclEntryFlag> flags;
+
+        private Builder(AclEntryType type,
+                        UserPrincipal who,
+                        Set<AclEntryPermission> perms,
+                        Set<AclEntryFlag> flags)
+        {
+            assert perms != null && flags != null;
+            this.type = type;
+            this.who = who;
+            this.perms = perms;
+            this.flags = flags;
+        }
+
+        /**
+         * Constructs an {@link AclEntry} from the components of this builder.
+         * The type and who components are required to have been set in order
+         * to construct an {@code AclEntry}.
+         *
+         * @return  A new ACL entry
+         *
+         * @throws  IllegalStateException
+         *          If the type or who component have not been set.
+         */
+        public AclEntry build() {
+            if (type == null)
+                throw new IllegalStateException("Missing type component");
+            if (who == null)
+                throw new IllegalStateException("Missing who component");
+            return new AclEntry(type, who, perms, flags);
+        }
+
+        /**
+         * Sets the type component of this builder.
+         *
+         * @return  This builder
+         */
+        public Builder setType(AclEntryType type) {
+            if (type == null)
+                throw new NullPointerException();
+            this.type = type;
+            return this;
+        }
+
+        /**
+         * Sets the principal component of this builder.
+         *
+         * @return  This builder
+         */
+        public Builder setPrincipal(UserPrincipal who) {
+            if (who == null)
+                throw new NullPointerException();
+            this.who = who;
+            return this;
+        }
+
+        // check set only contains elements of the given type
+        private static void checkSet(Set<?> set, Class<?> type) {
+            for (Object e: set) {
+                if (e == null)
+                    throw new NullPointerException();
+                type.cast(e);
+            }
+        }
+
+        /**
+         * Sets the permissions component of this builder. On return, the
+         * permissions component of this builder is a copy of the given set.
+         *
+         * @return  This builder
+         *
+         * @throws  ClassCastException
+         *          If the sets contains elements that are not of type {@code
+         *          AclEntryPermission}
+         */
+        public Builder setPermissions(Set<AclEntryPermission> perms) {
+            // copy and check for erroneous elements
+            perms = new HashSet<AclEntryPermission>(perms);
+            checkSet(perms, AclEntryPermission.class);
+            this.perms = perms;
+            return this;
+        }
+
+        /**
+         * Sets the permissions component of this builder. On return, the
+         * permissions component of this builder is a copy of the permissions in
+         * the given array.
+         *
+         * @return  This builder
+         */
+        public Builder setPermissions(AclEntryPermission... perms) {
+            Set<AclEntryPermission> set =
+                new HashSet<AclEntryPermission>(perms.length);
+            // copy and check for null elements
+            for (AclEntryPermission p: perms) {
+                if (p == null)
+                    throw new NullPointerException();
+                set.add(p);
+            }
+            this.perms = set;
+            return this;
+        }
+
+        /**
+         * Sets the flags component of this builder. On return, the flags
+         * component of this builder is a copy of the given set.
+         *
+         * @return  This builder
+         *
+         * @throws  ClassCastException
+         *          If the sets contains elements that are not of type {@code
+         *          AclEntryFlag}
+         */
+        public Builder setFlags(Set<AclEntryFlag> flags) {
+            // copy and check for erroneous elements
+            flags = new HashSet<AclEntryFlag>(flags);
+            checkSet(flags, AclEntryFlag.class);
+            this.flags = flags;
+            return this;
+        }
+
+        /**
+         * Sets the flags component of this builder. On return, the flags
+         * component of this builder is a copy of the flags in the given
+         * array.
+         *
+         * @return  This builder
+         */
+        public Builder setFlags(AclEntryFlag... flags) {
+            Set<AclEntryFlag> set = new HashSet<AclEntryFlag>(flags.length);
+            // copy and check for null elements
+            for (AclEntryFlag f: flags) {
+                if (f == null)
+                    throw new NullPointerException();
+                set.add(f);
+            }
+            this.flags = set;
+            return this;
+        }
+    }
+
+    /**
+     * Constructs a new builder. The initial value of the type and who
+     * components is {@code null}. The initial value of the permissions and
+     * flags components is the empty set.
+     *
+     * @return  A new builder
+     */
+    public static Builder newBuilder() {
+        Set<AclEntryPermission> perms = Collections.emptySet();
+        Set<AclEntryFlag> flags = Collections.emptySet();
+        return new Builder(null, null, perms, flags);
+    }
+
+    /**
+     * Constructs a new builder with the components of an existing ACL entry.
+     *
+     * @param   entry
+     *          An ACL entry
+     *
+     * @return  A new builder
+     */
+    public static Builder newBuilder(AclEntry entry) {
+        return new Builder(entry.type, entry.who, entry.perms, entry.flags);
+    }
+
+    /**
+     * Returns the ACL entry type.
+     */
+    public AclEntryType type() {
+        return type;
+    }
+
+    /**
+     * Returns the principal component.
+     */
+    public UserPrincipal principal() {
+        return who;
+    }
+
+    /**
+     * Returns a copy of the permissions component.
+     *
+     * <p> The returned set is a modifiable copy of the permissions.
+     */
+    public Set<AclEntryPermission> permissions() {
+        return new HashSet<AclEntryPermission>(perms);
+    }
+
+    /**
+     * Returns a copy of the flags component.
+     *
+     * <p> The returned set is a modifiable copy of the flags.
+     */
+    public Set<AclEntryFlag> flags() {
+        return new HashSet<AclEntryFlag>(flags);
+    }
+
+    /**
+     * Compares the specified object with this ACL entry for equality.
+     *
+     * <p> If the given object is not an {@code AclEntry} then this method
+     * immediately returns {@code false}.
+     *
+     * <p> For two ACL entries to be considered equals requires that they are
+     * both the same type, their who components are equal, their permissions
+     * components are equal, and their flags components are equal.
+     *
+     * <p> This method satisfies the general contract of the {@link
+     * java.lang.Object#equals(Object) Object.equals} method. </p>
+     *
+     * @param   ob   The object to which this object is to be compared
+     *
+     * @return  {@code true} if, and only if, the given object is an AclEntry that
+     *          is identical to this AclEntry
+     */
+    @Override
+    public boolean equals(Object ob) {
+        if (ob == this)
+            return true;
+        if (ob == null || !(ob instanceof AclEntry))
+            return false;
+        AclEntry other = (AclEntry)ob;
+        if (this.type != other.type)
+            return false;
+        if (!this.who.equals(other.who))
+            return false;
+        if (!this.perms.equals(other.perms))
+            return false;
+        if (!this.flags.equals(other.flags))
+            return false;
+        return true;
+    }
+
+    private static int hash(int h, Object o) {
+        return h * 127 + o.hashCode();
+    }
+
+    /**
+     * Returns the hash-code value for this ACL entry.
+     *
+     * <p> This method satisfies the general contract of the {@link
+     * Object#hashCode method}.
+     */
+    @Override
+    public int hashCode() {
+        // return cached hash if available
+        if (hash != 0)
+            return hash;
+        int h = type.hashCode();
+        h = hash(h, who);
+        h = hash(h, perms);
+        h = hash(h, flags);
+        hash = h;
+        return hash;
+    }
+
+    /**
+     * Returns the string representation of this ACL entry.
+     *
+     * @return  The string representation of this entry
+     */
+    @Override
+    public String toString() {
+        StringBuilder sb = new StringBuilder();
+
+        // who
+        sb.append(who.getName());
+        sb.append(':');
+
+        // permissions
+        for (AclEntryPermission perm: perms) {
+            sb.append(perm.name());
+            sb.append('/');
+        }
+        sb.setLength(sb.length()-1); // drop final slash
+        sb.append(':');
+
+        // flags
+        if (!flags.isEmpty()) {
+            for (AclEntryFlag flag: flags) {
+                sb.append(flag.name());
+                sb.append('/');
+            }
+            sb.setLength(sb.length()-1);  // drop final slash
+            sb.append(':');
+        }
+
+        // type
+        sb.append(type.name());
+        return sb.toString();
+    }
+}