1 /* 2 * Copyright (c) 2000, 2006, Oracle and/or its affiliates. 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. Oracle designates this 8 * particular file as subject to the "Classpath" exception as provided 9 * by Oracle 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 22 * or visit www.oracle.com if you need additional information or have any 23 * 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 } 179
