/*

  * 

  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.

  * 

  * Copyright 2007-2008 Sun Microsystems, Inc. All rights reserved.

  * 

  * The contents of this file are subject to the terms of either the GNU

  * General Public License Version 2 only ("GPL") or the Common Development

  * and Distribution License("CDDL") (collectively, the "License").  You

  * may not use this file except in compliance with the License. You can obtain

  * a copy of the License at https://glassfish.dev.java.net/public/CDDL+GPL.html

  * or glassfish/bootstrap/legal/LICENSE.txt.  See the License for the specific

  * language governing permissions and limitations under the License.

  * 

  * When distributing the software, include this License Header Notice in each

  * file and include the License file at glassfish/bootstrap/legal/LICENSE.txt.

  * Sun designates this particular file as subject to the "Classpath" exception

  * as provided by Sun in the GPL Version 2 section of the License file that

  * accompanied this code.  If applicable, add the following below the License

  * Header, with the fields enclosed by brackets [] replaced by your own

  * identifying information: "Portions Copyrighted [year]

  * [name of copyright owner]"

  * 

  * Contributor(s):

  * 

  * If you wish your version of this file to be governed by only the CDDL or

  * only the GPL Version 2, indicate your decision by adding "[Contributor]

  * elects to include this software in this distribution under the [CDDL or GPL

  * Version 2] license."  If you don't indicate a single choice of license, a

  * recipient has the option to distribute your version of this file under

  * either the CDDL, the GPL Version 2 or to extend the choice of license to

  * its licensees as provided above.  However, if you add GPL Version 2 code

  * and therefore, elected the GPL Version 2 license, then the option applies

  * only if the new code is made subject to such option by the copyright

  * holder.

  *

  */

 package com.sun.grizzly.connectioncache.spi.transport;

 import java.io.Closeable;

 /** A connection cache manages a group of connections which may be re-used

  * for sending and receiving messages.

  * @param C  a connection

  */

 public interface ConnectionCache<C extends Closeable> {

     /** User-provided indentifier for an instance of the 

      * {@link ConnectionCache}.

      * @return  a <code>String</code> identifying an instance of a {@link ConnectionCache}

      */

     String getCacheType() ;

     /** Total number of connections currently managed by the cache.

      * @return  number of connections currently managed by the cache

      */

     long numberOfConnections() ;

     /** Number of idle connections; that is, connections for which the number of

      * get/release or responseReceived/responseProcessed calls are equal.

      * @return  number of idle connections

      */

     long numberOfIdleConnections() ;

     /** Number of non-idle connections.  Normally, busy+idle==total, but this

      * may not be strictly true due to concurrent updates to the connection 

      * cache.

      * @return  number of busy connections

      */

     long numberOfBusyConnections() ;

     /** Number of idle connections that are reclaimable.  Such connections

      * are not in use, and are not waiting to handle any responses.

      * @return  number of idle connections that are reclaimable

      */

     long numberOfReclaimableConnections() ;

     /** Threshold at which connection reclamation begins.

      * @return  threshold at which connection reclamation begins.

      */

     int highWaterMark() ;

     /** Number of connections to reclaim each time reclamation starts.

      * @return  number of connections to reclaim

      */

     int numberToReclaim() ;

     /** Close a connection, regardless of its state.  This may cause requests

      * to fail to be sent, and responses to be lost.  Intended for 

      * handling serious errors, such as loss of framing on a TCP stream,

      * that require closing the connection.

      * @param conn  a connection

      */

     void close( final C conn ) ;

 }