Java example source code file (PooledConnection.java)

This example Java source code file (PooledConnection.java) is included in the alvinalexander.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Learn more about this Java project at its project page.

Java - Java tags/keywords

connection, jdbc, pooledconnection, sql, sqlexception

The PooledConnection.java Java example source code

/*
 * Copyright (c) 2000, 2013, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */

package javax.sql;

import java.sql.Connection;
import java.sql.SQLException;

/**
 * An object that provides hooks for connection pool management.
 * A <code>PooledConnection object
 * represents a physical connection to a data source.  The connection
 * can be recycled rather than being closed when an application is
 * finished with it, thus reducing the number of connections that
 * need to be made.
 * <P>
 * An application programmer does not use the <code>PooledConnection
 * interface directly; rather, it is used by a middle tier infrastructure
 * that manages the pooling of connections.
 * <P>
 * When an application calls the method <code>DataSource.getConnection,
 * it gets back a <code>Connection object.  If connection pooling is
 * being done, that <code>Connection object is actually a handle to
 * a <code>PooledConnection object, which is a physical connection.
 * <P>
 * The connection pool manager, typically the application server, maintains
 * a pool of <code>PooledConnection objects.  If there is a
 * <code>PooledConnection object available in the pool, the
 * connection pool manager returns a <code>Connection object that
 * is a handle to that physical connection.
 * If no <code>PooledConnection object is available, the
 * connection pool manager calls the <code>ConnectionPoolDataSource
 * method <code>getPoolConnection to create a new physical connection.  The
 *  JDBC driver implementing <code>ConnectionPoolDataSource creates a
 *  new <code>PooledConnection object and returns a handle to it.
 * <P>
 * When an application closes a connection, it calls the <code>Connection
 * method <code>close. When connection pooling is being done,
 * the connection pool manager is notified because it has registered itself as
 * a <code>ConnectionEventListener object using the
 * <code>ConnectionPool method addConnectionEventListener.
 * The connection pool manager deactivates the handle to
 * the <code>PooledConnection object and  returns the
 * <code>PooledConnection object to the pool of connections so that
 * it can be used again.  Thus, when an application closes its connection,
 * the underlying physical connection is recycled rather than being closed.
 * <P>
 * The physical connection is not closed until the connection pool manager
 * calls the <code>PooledConnection method close.
 * This method is generally called to have an orderly shutdown of the server or
 * if a fatal error has made the connection unusable.
 *
 * <p>
 * A connection pool manager is often also a statement pool manager, maintaining
 *  a pool of <code>PreparedStatement objects.
 *  When an application closes a prepared statement, it calls the
 *  <code>PreparedStatement
 * method <code>close. When Statement pooling is being done,
 * the pool manager is notified because it has registered itself as
 * a <code>StatementEventListener object using the
 * <code>ConnectionPool method addStatementEventListener.
 *  Thus, when an application closes its  <code>PreparedStatement,
 * the underlying prepared statement is recycled rather than being closed.
 * <P>
 *
 * @since 1.4
 */

public interface PooledConnection {

  /**
   * Creates and returns a <code>Connection object that is a handle
   * for the physical connection that
   * this <code>PooledConnection object represents.
   * The connection pool manager calls this method when an application has
   * called the method <code>DataSource.getConnection and there are
   * no <code>PooledConnection objects available. See the
   * {@link PooledConnection interface description} for more information.
   *
   * @return  a <code>Connection object that is a handle to
   *          this <code>PooledConnection object
   * @exception SQLException if a database access error occurs
   * @exception java.sql.SQLFeatureNotSupportedException if the JDBC driver does not support
   * this method
   * @since 1.4
   */
  Connection getConnection() throws SQLException;

  /**
   * Closes the physical connection that this <code>PooledConnection
   * object represents.  An application never calls this method directly;
   * it is called by the connection pool module, or manager.
   * <P>
   * See the {@link PooledConnection interface description} for more
   * information.
   *
   * @exception SQLException if a database access error occurs
   * @exception java.sql.SQLFeatureNotSupportedException if the JDBC driver does not support
   * this method
   * @since 1.4
   */
  void close() throws SQLException;

  /**
   * Registers the given event listener so that it will be notified
   * when an event occurs on this <code>PooledConnection object.
   *
   * @param listener a component, usually the connection pool manager,
   *        that has implemented the
   *        <code>ConnectionEventListener interface and wants to be
   *        notified when the connection is closed or has an error
   * @see #removeConnectionEventListener
   */
  void addConnectionEventListener(ConnectionEventListener listener);

  /**
   * Removes the given event listener from the list of components that
   * will be notified when an event occurs on this
   * <code>PooledConnection object.
   *
   * @param listener a component, usually the connection pool manager,
   *        that has implemented the
   *        <code>ConnectionEventListener interface and
   *        been registered with this <code>PooledConnection object as
   *        a listener
   * @see #addConnectionEventListener
   */
  void removeConnectionEventListener(ConnectionEventListener listener);

        /**
         * Registers a <code>StatementEventListener with this PooledConnection object.  Components that
         * wish to be notified when  <code>PreparedStatements created by the
         * connection are closed or are detected to be invalid may use this method
         * to register a <code>StatementEventListener with this PooledConnection object.
         * <p>
         * @param listener      an component which implements the <code>StatementEventListener
         *                                      interface that is to be registered with this <code>PooledConnection object
         * <p>
         * @since 1.6
         */
        public void addStatementEventListener(StatementEventListener listener);

        /**
         * Removes the specified <code>StatementEventListener from the list of
         * components that will be notified when the driver detects that a
         * <code>PreparedStatement has been closed or is invalid.
         * <p>
         * @param listener      the component which implements the
         *                                      <code>StatementEventListener interface that was previously
         *                                      registered with this <code>PooledConnection object
         * <p>
         * @since 1.6
         */
        public void removeStatementEventListener(StatementEventListener listener);

 }