Coverage Report - com.sun.grizzly.connectioncache.spi.transport.OutboundConnectionCache
 
Classes in this File Line Coverage Branch Coverage Complexity
OutboundConnectionCache
N/A
N/A
0
 
 1  
 /*
 2  
  * 
 3  
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
 4  
  * 
 5  
  * Copyright 2007-2008 Sun Microsystems, Inc. All rights reserved.
 6  
  * 
 7  
  * The contents of this file are subject to the terms of either the GNU
 8  
  * General Public License Version 2 only ("GPL") or the Common Development
 9  
  * and Distribution License("CDDL") (collectively, the "License").  You
 10  
  * may not use this file except in compliance with the License. You can obtain
 11  
  * a copy of the License at https://glassfish.dev.java.net/public/CDDL+GPL.html
 12  
  * or glassfish/bootstrap/legal/LICENSE.txt.  See the License for the specific
 13  
  * language governing permissions and limitations under the License.
 14  
  * 
 15  
  * When distributing the software, include this License Header Notice in each
 16  
  * file and include the License file at glassfish/bootstrap/legal/LICENSE.txt.
 17  
  * Sun designates this particular file as subject to the "Classpath" exception
 18  
  * as provided by Sun in the GPL Version 2 section of the License file that
 19  
  * accompanied this code.  If applicable, add the following below the License
 20  
  * Header, with the fields enclosed by brackets [] replaced by your own
 21  
  * identifying information: "Portions Copyrighted [year]
 22  
  * [name of copyright owner]"
 23  
  * 
 24  
  * Contributor(s):
 25  
  * 
 26  
  * If you wish your version of this file to be governed by only the CDDL or
 27  
  * only the GPL Version 2, indicate your decision by adding "[Contributor]
 28  
  * elects to include this software in this distribution under the [CDDL or GPL
 29  
  * Version 2] license."  If you don't indicate a single choice of license, a
 30  
  * recipient has the option to distribute your version of this file under
 31  
  * either the CDDL, the GPL Version 2 or to extend the choice of license to
 32  
  * its licensees as provided above.  However, if you add GPL Version 2 code
 33  
  * and therefore, elected the GPL Version 2 license, then the option applies
 34  
  * only if the new code is made subject to such option by the copyright
 35  
  * holder.
 36  
  *
 37  
  */
 38  
 
 39  
 package com.sun.grizzly.connectioncache.spi.transport;
 40  
 
 41  
 import java.io.Closeable;
 42  
 import java.io.IOException ;
 43  
 
 44  
 /** A concurrent mostly non-blocking connection cache.  Here a Connection is an 
 45  
  * abstraction of a Socket or SocketChannel: basically some sort of resource 
 46  
  * that is expensive to acquire, and can be re-used freely.  The cache 
 47  
  * maintains a loose upper bound on the number of cached connections, and 
 48  
  * reclaims connections as needed.
 49  
  * <P>
 50  
  * This cache places minimal requirements on the Connections that it contains:
 51  
  * <ol>
 52  
  * <li>A Connection must implement a close() method.  This is called when idle
 53  
  * connections are reclaimed.
 54  
  * <li>A Connection must be usable as a HashMap key.  
 55  
  * <li>There must be a ContactInfo class that is used to create Connection 
 56  
  * instances.  The ContactInfo class must support a create() method that 
 57  
  * returns a Connection.
 58  
  * <li>The ContactInfo must be usable as a HashMap key.
 59  
  * <li>All instances created from a ContactInfo are equal; that is, any request
 60  
  * sent to a particular ContactInfo can used an instance created from that 
 61  
  * ContactInfo.  For example, in the CORBA case, IP host and port is not always
 62  
  * sufficient: we may also need the Codeset type that indicates how Strings are
 63  
  * encoded.  Basically, protocols (like GIOP) that bind session state to a 
 64  
  * Connection may need more than transport information in the ContactInfo.
 65  
  * </ol>
 66  
  * <P>
 67  
  * Some simple methods are provided for monitoring the state of the cache:
 68  
  * numbers of busy and idle connections, and the total number of connections in 
 69  
  * the cache.
 70  
  * 
 71  
  * @param C a connection
 72  
  */
 73  
 public interface OutboundConnectionCache<C extends Closeable> 
 74  
     extends ConnectionCache<C> {
 75  
     /** Configured maximum number of connections supported per ContactInfo.
 76  
      * @return  maximum number of connections supported per <code>ContactInfo</code>
 77  
      */
 78  
     int maxParallelConnections() ;
 79  
 
 80  
     /** Determine whether a new connection could be created by the
 81  
      * ConnectionCache or not.
 82  
      * @param cinfo  a <code>ContactInfo</code>
 83  
      * @return  true if new connection could be created by {@link ConnectionCache}, otherwise false.
 84  
      */
 85  
     boolean canCreateNewConnection( ContactInfo<C> cinfo ) ;
 86  
 
 87  
     /** Return a Connection corresponding to the given ContactInfo.
 88  
      * This works as follows:
 89  
      * <ul>
 90  
      * <li>Call the finder.  If it returns non-null, use that connection;
 91  
      * (Note that this may be a new connection, created in the finder)
 92  
      * <li>otherwise, Use an idle connection, if one is available; 
 93  
      * <li>otherwise, create a new connection, if not too many connections are 
 94  
      * open;
 95  
      * <li>otherwise, use a busy connection.
 96  
      * </ul>
 97  
      * Note that creating a new connection requires EITHER:
 98  
      * <ul>
 99  
      * <li>there is no existing connection for the ContactInfo 
 100  
      * <li> OR the total number of connections in the cache is less than the
 101  
      * HighWaterMark and the number of connections for this ContactInfo
 102  
      * is less than MaxParallelConnections.  
 103  
      * </ul>
 104  
      * We will always return a 
 105  
      * Connection for a get call UNLESS we have no existing connection and
 106  
      * an attempt to create a new connection fails.  In this case, the
 107  
      * IOException thrown by ContactInfo.create is propagated out of this
 108  
      * method.
 109  
      * <P>
 110  
      * It is possible that the cache contains connections that no longer connect
 111  
      * to their destination.  In this case, it is the responsibility of the 
 112  
      * client of the cache to close the broken connection as they are detected.
 113  
      * Connection reclamation may also handle the cleanup, but note that a 
 114  
      * broken connection with pending responses will never be reclaimed.
 115  
      * <P>
 116  
      * Note that the idle and busy connection collections that are
 117  
      * passed to the finder are unmodifiable collections.  They have iterators 
 118  
      * that return connections in LRU order, with the least recently used 
 119  
      * connection first.  This is done to aid a finder that wishes to consider 
 120  
      * load balancing in its determination of an appropriate connection.
 121  
      * <P>
 122  
      * @param cinfo  a <code>ContactInfo</code>
 123  
      * @param finder  a <code>ConnectionFinder</code>
 124  
      * @return  a connection
 125  
      * @throws java.io.IOException 
 126  
      */
 127  
     C get( ContactInfo<C> cinfo, ConnectionFinder<C> finder 
 128  
         ) throws IOException ;
 129  
 
 130  
     /** Behaves the same as get( ContactInfo<C>, ConnectionFinder<C> ) 
 131  
      * except that no connection finder is provided, so that step is
 132  
      * ignored. 
 133  
      * @param cinfo  a <code>ContactInfo</code>
 134  
      * @return  a connection
 135  
      * @throws java.io.IOException 
 136  
      */
 137  
     C get( ContactInfo<C> cinfo ) throws IOException ;
 138  
 
 139  
     /** Release a Connection previously obtained from get.  Connections that
 140  
      * have been released as many times as they have been returned by
 141  
      * get are idle; otherwise a Connection is busy.  Some number of
 142  
      * responses (usually 0 or 1) may be expected ON THE SAME CONNECTION
 143  
      * even for an idle connection.  We maintain a count of the number of 
 144  
      * outstanding responses we expect for protocols that return the response
 145  
      * on the same connection on which the request was received.  This is
 146  
      * necessary to prevent reclamation of a Connection that is idle, but
 147  
      * still needed to send responses to old requests.
 148  
      * @param conn  a connection
 149  
      * @param numResponseExpected  number of connections in which a response is expected
 150  
      */
 151  
     void release( C conn, int numResponseExpected ) ;
 152  
 
 153  
     /** Inform the cache that a response has been received on a particular
 154  
      * connection.  This must also be called in the event that no response
 155  
      * is received, but the client times out waiting for a response, and
 156  
      * decides to abandon the request.
 157  
      * <P>
 158  
      * When a Connection is idle, and has no pending responses, it is
 159  
      * eligible for reclamation.
 160  
      * @param conn  a connection
 161  
      */
 162  
     void responseReceived( C conn ) ;
 163  
 }