| J. Duke | 319a3b9 | 2007-12-01 00:00:00 +0000 | [diff] [blame^] | 1 | /* |
| 2 | * Copyright 2003 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.jndi.ldap.pool; |
| 27 | |
| 28 | import java.lang.ref.WeakReference; |
| 29 | import java.lang.ref.ReferenceQueue; |
| 30 | |
| 31 | /* |
| 32 | * This class defines a WeakReference to the ConnectionRef (the referent). |
| 33 | * |
| 34 | * The ConnectionRef enables to break the reference |
| 35 | * cycle between Connection, LdapClient, Connections and ConnectionDesc, |
| 36 | * shown in the figure below. |
| 37 | * |
| 38 | * -------> Connections -----> ConnectionDesc |
| 39 | * | ^ | |
| 40 | * | | | |
| 41 | * | | | |
| 42 | * ConnectionsRef LdapClient <------------ |
| 43 | * ^ | ^ |
| 44 | * : | | |
| 45 | * : v | |
| 46 | * ConnectionsWeakRef Connection |
| 47 | * |
| 48 | * The ConnectionsRef is for cleaning up the resources held by the |
| 49 | * Connection thread by making them available to the GC. The pool |
| 50 | * uses ConnectionRef to hold the pooled resources. |
| 51 | * |
| 52 | * This class in turn holds a WeakReference with a ReferenceQueue to the |
| 53 | * ConnectionRef to track when the ConnectionRef becomes ready |
| 54 | * for getting GC'ed. It extends from WeakReference in order to hold a |
| 55 | * reference to Connections used for closing (which in turn terminates |
| 56 | * the Connection thread) it by monitoring the ReferenceQueue. |
| 57 | */ |
| 58 | class ConnectionsWeakRef extends WeakReference { |
| 59 | |
| 60 | private final Connections conns; |
| 61 | |
| 62 | ConnectionsWeakRef (ConnectionsRef connsRef, ReferenceQueue queue) { |
| 63 | super(connsRef, queue); |
| 64 | this.conns = connsRef.getConnections(); |
| 65 | } |
| 66 | |
| 67 | Connections getConnections() { |
| 68 | return conns; |
| 69 | } |
| 70 | } |