J. Duke | 319a3b9 | 2007-12-01 00:00:00 +0000 | [diff] [blame^] | 1 | /* |
| 2 | * Copyright 2000-2006 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 javax.sql; |
| 27 | |
| 28 | import java.sql.Connection; |
| 29 | import java.sql.SQLException; |
| 30 | |
| 31 | /** |
| 32 | * An object that provides hooks for connection pool management. |
| 33 | * A <code>PooledConnection</code> object |
| 34 | * represents a physical connection to a data source. The connection |
| 35 | * can be recycled rather than being closed when an application is |
| 36 | * finished with it, thus reducing the number of connections that |
| 37 | * need to be made. |
| 38 | * <P> |
| 39 | * An application programmer does not use the <code>PooledConnection</code> |
| 40 | * interface directly; rather, it is used by a middle tier infrastructure |
| 41 | * that manages the pooling of connections. |
| 42 | * <P> |
| 43 | * When an application calls the method <code>DataSource.getConnection</code>, |
| 44 | * it gets back a <code>Connection</code> object. If connection pooling is |
| 45 | * being done, that <code>Connection</code> object is actually a handle to |
| 46 | * a <code>PooledConnection</code> object, which is a physical connection. |
| 47 | * <P> |
| 48 | * The connection pool manager, typically the application server, maintains |
| 49 | * a pool of <code>PooledConnection</code> objects. If there is a |
| 50 | * <code>PooledConnection</code> object available in the pool, the |
| 51 | * connection pool manager returns a <code>Connection</code> object that |
| 52 | * is a handle to that physical connection. |
| 53 | * If no <code>PooledConnection</code> object is available, the |
| 54 | * connection pool manager calls the <code>ConnectionPoolDataSource</code> |
| 55 | * method <code>getPoolConnection</code> to create a new physical connection. The |
| 56 | * JDBC driver implementing <code>ConnectionPoolDataSource</code> creates a |
| 57 | * new <code>PooledConnection</code> object and returns a handle to it. |
| 58 | * <P> |
| 59 | * When an application closes a connection, it calls the <code>Connection</code> |
| 60 | * method <code>close</code>. When connection pooling is being done, |
| 61 | * the connection pool manager is notified because it has registered itself as |
| 62 | * a <code>ConnectionEventListener</code> object using the |
| 63 | * <code>ConnectionPool</code> method <code>addConnectionEventListener</code>. |
| 64 | * The connection pool manager deactivates the handle to |
| 65 | * the <code>PooledConnection</code> object and returns the |
| 66 | * <code>PooledConnection</code> object to the pool of connections so that |
| 67 | * it can be used again. Thus, when an application closes its connection, |
| 68 | * the underlying physical connection is recycled rather than being closed. |
| 69 | * <P> |
| 70 | * The physical connection is not closed until the connection pool manager |
| 71 | * calls the <code>PooledConnection</code> method <code>close</code>. |
| 72 | * This method is generally called to have an orderly shutdown of the server or |
| 73 | * if a fatal error has made the connection unusable. |
| 74 | * |
| 75 | * <p> |
| 76 | * A connection pool manager is often also a statement pool manager, maintining |
| 77 | * a pool of <code>PreparedStatement</code> objects. |
| 78 | * When an application closes a prepared statement, it calls the |
| 79 | * <code>PreparedStatement</code> |
| 80 | * method <code>close</code>. When <code>Statement</code> pooling is being done, |
| 81 | * the pool manager is notified because it has registered itself as |
| 82 | * a <code>StatementEventListener</code> object using the |
| 83 | * <code>ConnectionPool</code> method <code>addStatementEventListener</code>. |
| 84 | * Thus, when an application closes its <code>PreparedStatement</code>, |
| 85 | * the underlying prepared statement is recycled rather than being closed. |
| 86 | * <P> |
| 87 | * |
| 88 | * @since 1.4 |
| 89 | */ |
| 90 | |
| 91 | public interface PooledConnection { |
| 92 | |
| 93 | /** |
| 94 | * Creates and returns a <code>Connection</code> object that is a handle |
| 95 | * for the physical connection that |
| 96 | * this <code>PooledConnection</code> object represents. |
| 97 | * The connection pool manager calls this method when an application has |
| 98 | * called the method <code>DataSource.getConnection</code> and there are |
| 99 | * no <code>PooledConnection</code> objects available. See the |
| 100 | * {@link PooledConnection interface description} for more information. |
| 101 | * |
| 102 | * @return a <code>Connection</code> object that is a handle to |
| 103 | * this <code>PooledConnection</code> object |
| 104 | * @exception SQLException if a database access error occurs |
| 105 | * @exception SQLFeatureNotSupportedException if the JDBC driver does not support |
| 106 | * this method |
| 107 | * @since 1.4 |
| 108 | */ |
| 109 | Connection getConnection() throws SQLException; |
| 110 | |
| 111 | /** |
| 112 | * Closes the physical connection that this <code>PooledConnection</code> |
| 113 | * object represents. An application never calls this method directly; |
| 114 | * it is called by the connection pool module, or manager. |
| 115 | * <P> |
| 116 | * See the {@link PooledConnection interface description} for more |
| 117 | * information. |
| 118 | * |
| 119 | * @exception SQLException if a database access error occurs |
| 120 | * @exception SQLFeatureNotSupportedException if the JDBC driver does not support |
| 121 | * this method |
| 122 | * @since 1.4 |
| 123 | */ |
| 124 | void close() throws SQLException; |
| 125 | |
| 126 | /** |
| 127 | * Registers the given event listener so that it will be notified |
| 128 | * when an event occurs on this <code>PooledConnection</code> object. |
| 129 | * |
| 130 | * @param listener a component, usually the connection pool manager, |
| 131 | * that has implemented the |
| 132 | * <code>ConnectionEventListener</code> interface and wants to be |
| 133 | * notified when the connection is closed or has an error |
| 134 | * @see #removeConnectionEventListener |
| 135 | */ |
| 136 | void addConnectionEventListener(ConnectionEventListener listener); |
| 137 | |
| 138 | /** |
| 139 | * Removes the given event listener from the list of components that |
| 140 | * will be notified when an event occurs on this |
| 141 | * <code>PooledConnection</code> object. |
| 142 | * |
| 143 | * @param listener a component, usually the connection pool manager, |
| 144 | * that has implemented the |
| 145 | * <code>ConnectionEventListener</code> interface and |
| 146 | * been registered with this <code>PooledConnection</code> object as |
| 147 | * a listener |
| 148 | * @see #addConnectionEventListener |
| 149 | */ |
| 150 | void removeConnectionEventListener(ConnectionEventListener listener); |
| 151 | |
| 152 | /** |
| 153 | * Registers a <code>StatementEventListener</code> with this <code>PooledConnection</code> object. Components that |
| 154 | * wish to be notified when <code>PreparedStatement</code>s created by the |
| 155 | * connection are closed or are detected to be invalid may use this method |
| 156 | * to register a <code>StatementEventListener</code> with this <code>PooledConnection</code> object. |
| 157 | * <p> |
| 158 | * @param listener an component which implements the <code>StatementEventListener</code> |
| 159 | * interface that is to be registered with this <code>PooledConnection</code> object |
| 160 | * <p> |
| 161 | * @since 1.6 |
| 162 | */ |
| 163 | public void addStatementEventListener(StatementEventListener listener); |
| 164 | |
| 165 | /** |
| 166 | * Removes the specified <code>StatementEventListener</code> from the list of |
| 167 | * components that will be notified when the driver detects that a |
| 168 | * <code>PreparedStatement</code> has been closed or is invalid. |
| 169 | * <p> |
| 170 | * @param listener the component which implements the |
| 171 | * <code>StatementEventListener</code> interface that was previously |
| 172 | * registered with this <code>PooledConnection</code> object |
| 173 | * <p> |
| 174 | * @since 1.6 |
| 175 | */ |
| 176 | public void removeStatementEventListener(StatementEventListener listener); |
| 177 | |
| 178 | } |