/*

 * Copyright (c) 2003, 2011, 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

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

package com.sun.jndi.ldap.pool;

import java.lang.ref.WeakReference;

import java.lang.ref.ReferenceQueue;

/*

 * This class defines a WeakReference to the ConnectionRef (the referent).

 *

 * The ConnectionRef enables to break the reference

 * cycle between Connection, LdapClient, Connections and ConnectionDesc,

 * shown in the figure below.

 *

 *        -------> Connections -----> ConnectionDesc

 *        |              ^                  |

 *        |              |                  |

 *        |              |                  |

 * ConnectionsRef    LdapClient <------------

 *        ^              |   ^

 *        :              |   |

 *        :              v   |

 * ConnectionsWeakRef  Connection

 *

 * The ConnectionsRef is for cleaning up the resources held by the

 * Connection thread by making them available to the GC. The pool

 * uses ConnectionRef to hold the pooled resources.

 *

 * This class in turn holds a WeakReference with a ReferenceQueue to the

 * ConnectionRef to track when the ConnectionRef becomes ready

 * for getting GC'ed. It extends from WeakReference in order to hold a

 * reference to Connections used for closing (which in turn terminates

 * the Connection thread) it by monitoring the ReferenceQueue.

 */

class ConnectionsWeakRef extends WeakReference<ConnectionsRef> {

    private final Connections conns;

    ConnectionsWeakRef (ConnectionsRef connsRef,

                        ReferenceQueue<? super ConnectionsRef> queue) {

        super(connsRef, queue);

        this.conns = connsRef.getConnections();

    }

    Connections getConnections() {

        return conns;

    }

}