/*
* Copyright (c) 2005, 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
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*/
package com.sun.jmx.mbeanserver;
import java.lang.ref.WeakReference;
import java.util.WeakHashMap;
import javax.management.Descriptor;
import javax.management.ImmutableDescriptor;
import javax.management.JMX;
public class DescriptorCache {
private DescriptorCache() {
}
static DescriptorCache getInstance() {
return instance;
}
public static DescriptorCache getInstance(JMX proof) {
if (proof != null)
return instance;
else
return null;
}
public ImmutableDescriptor get(ImmutableDescriptor descriptor) {
WeakReference<ImmutableDescriptor> wr = map.get(descriptor);
ImmutableDescriptor got = (wr == null) ? null : wr.get();
if (got != null)
return got;
map.put(descriptor, new WeakReference<ImmutableDescriptor>(descriptor));
return descriptor;
}
public ImmutableDescriptor union(Descriptor... descriptors) {
return get(ImmutableDescriptor.union(descriptors));
}
private final static DescriptorCache instance = new DescriptorCache();
private final WeakHashMap<ImmutableDescriptor,
WeakReference<ImmutableDescriptor>>
map = new WeakHashMap<ImmutableDescriptor,
WeakReference<ImmutableDescriptor>>();
}