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 }