/*
* @(#)RegistryKey.java 1.10 06/10/10
*
* Copyright 1990-2008 Sun Microsystems, Inc. All Rights Reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER
*
* This program 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.
*
* This program 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 at /legal/license.txt).
*
* 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 or visit www.sun.com if you need additional
* information or have any questions.
*
*/
package com.sun.xlet.ixc;
import java.rmi.Remote;
/**
* Key for an object registry, held in a hashtable. This is a weak key that
* knows to clean up the hashtable it's in when it is collected. It also
* has an efficiency issue: it's equivalent to the remote object it
* refers to for hashing purposes. That means you can search for the
* referred-to object in the hashtable, without wrapping it in a
* RegistryKey instance.
* <p>
* It's important to note that two keys are equivalent only if the Remote
* object to which they refer are <i>identical</i>. Two remote objects
* that are != but are .equals() should <i>not</i> be treated as the same
* object!
*/
final class RegistryKey extends java.lang.ref.WeakReference {
private int hash;
RegistryKey(Remote referent) {
super(referent);
hash = referent.hashCode();
}
public int hashCode() {
return hash;
}
public boolean equals(Object other) {
if (other == this) {
return true;
// This isn't just an optimization. The operation of
// ImportRegistryImpl.unregisterStub depends on it. Once
// the weak ref gets cleared by the GC, the identity test is
// the only one that can succeed.
}
if (other instanceof Remote) {
return other == get();
} else if (other instanceof RegistryKey) {
Object r = get();
if (r == null) {
return false;
} else {
return r == (((RegistryKey) other).get());
}
} else {
return false;
}
}
}