J. Duke | 319a3b9 | 2007-12-01 00:00:00 +0000 | [diff] [blame^] | 1 | /* |
| 2 | * Copyright 2005 Sun Microsystems, Inc. All Rights Reserved. |
| 3 | * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| 4 | * |
| 5 | * This code is free software; you can redistribute it and/or modify it |
| 6 | * under the terms of the GNU General Public License version 2 only, as |
| 7 | * published by the Free Software Foundation. Sun designates this |
| 8 | * particular file as subject to the "Classpath" exception as provided |
| 9 | * by Sun in the LICENSE file that accompanied this code. |
| 10 | * |
| 11 | * This code is distributed in the hope that it will be useful, but WITHOUT |
| 12 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| 13 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| 14 | * version 2 for more details (a copy is included in the LICENSE file that |
| 15 | * accompanied this code). |
| 16 | * |
| 17 | * You should have received a copy of the GNU General Public License version |
| 18 | * 2 along with this work; if not, write to the Free Software Foundation, |
| 19 | * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| 20 | * |
| 21 | * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, |
| 22 | * CA 95054 USA or visit www.sun.com if you need additional information or |
| 23 | * have any questions. |
| 24 | */ |
| 25 | |
| 26 | package com.sun.jmx.mbeanserver; |
| 27 | |
| 28 | import java.lang.ref.WeakReference; |
| 29 | import java.util.WeakHashMap; |
| 30 | import javax.management.Descriptor; |
| 31 | import javax.management.ImmutableDescriptor; |
| 32 | import javax.management.JMX; |
| 33 | |
| 34 | public class DescriptorCache { |
| 35 | private DescriptorCache() { |
| 36 | } |
| 37 | |
| 38 | static DescriptorCache getInstance() { |
| 39 | return instance; |
| 40 | } |
| 41 | |
| 42 | public static DescriptorCache getInstance(JMX proof) { |
| 43 | if (proof != null) |
| 44 | return instance; |
| 45 | else |
| 46 | return null; |
| 47 | } |
| 48 | |
| 49 | public ImmutableDescriptor get(ImmutableDescriptor descriptor) { |
| 50 | WeakReference<ImmutableDescriptor> wr = map.get(descriptor); |
| 51 | ImmutableDescriptor got = (wr == null) ? null : wr.get(); |
| 52 | if (got != null) |
| 53 | return got; |
| 54 | map.put(descriptor, new WeakReference<ImmutableDescriptor>(descriptor)); |
| 55 | return descriptor; |
| 56 | } |
| 57 | |
| 58 | public ImmutableDescriptor union(Descriptor... descriptors) { |
| 59 | return get(ImmutableDescriptor.union(descriptors)); |
| 60 | } |
| 61 | |
| 62 | private final static DescriptorCache instance = new DescriptorCache(); |
| 63 | private final WeakHashMap<ImmutableDescriptor, |
| 64 | WeakReference<ImmutableDescriptor>> |
| 65 | map = new WeakHashMap<ImmutableDescriptor, |
| 66 | WeakReference<ImmutableDescriptor>>(); |
| 67 | } |