/*
* @(#)PooledConnection.java 1.16 06/04/16
*
* Copyright 2006 Sun Microsystems, Inc. All rights reserved.
* SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
*/
package javax.sql;
import java.sql.Connection;
import java.sql.SQLException;
/**
* An object that provides hooks for connection pool management.
* A <code>PooledConnection</code> 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</code>
* 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</code>,
* it gets back a <code>Connection</code> object. If connection pooling is
* being done, that <code>Connection</code> object is actually a handle to
* a <code>PooledConnection</code> object, which is a physical connection.
* <P>
* The connection pool manager, typically the application server, maintains
* a pool of <code>PooledConnection</code> objects. If there is a
* <code>PooledConnection</code> object available in the pool, the
* connection pool manager returns a <code>Connection</code> object that
* is a handle to that physical connection.
* If no <code>PooledConnection</code> object is available, the
* connection pool manager calls the <code>ConnectionPoolDataSource</code>
* method <code>getPoolConnection</code> to create a new physical connection. The
* JDBC driver implementing <code>ConnectionPoolDataSource</code> creates a
* new <code>PooledConnection</code> object and returns a handle to it.
* <P>
* When an application closes a connection, it calls the <code>Connection</code>
* method <code>close</code>. When connection pooling is being done,
* the connection pool manager is notified because it has registered itself as
* a <code>ConnectionEventListener</code> object using the
* <code>ConnectionPool</code> method <code>addConnectionEventListener</code>.
* The connection pool manager deactivates the handle to
* the <code>PooledConnection</code> object and returns the
* <code>PooledConnection</code> 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</code> method <code>close</code>.
* 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, maintining
* a pool of <code>PreparedStatement</code> objects.
* When an application closes a prepared statement, it calls the
* <code>PreparedStatement</code>
* method <code>close</code>. When <code>Statement</code> pooling is being done,
* the pool manager is notified because it has registered itself as
* a <code>StatementEventListener</code> object using the
* <code>ConnectionPool</code> method <code>addStatementEventListener</code>.
* Thus, when an application closes its <code>PreparedStatement</code>,
* the underlying prepared statement is recycled rather than being closed.
* <P>
*
* @since 1.4
*/
public interface PooledConnection {
/**
* Creates and returns a <code>Connection</code> object that is a handle
* for the physical connection that
* this <code>PooledConnection</code> object represents.
* The connection pool manager calls this method when an application has
* called the method <code>DataSource.getConnection</code> and there are
* no <code>PooledConnection</code> objects available. See the
* {@link PooledConnection interface description} for more information.
*
* @return a <code>Connection</code> object that is a handle to
* this <code>PooledConnection</code> object
* @exception SQLException if a database access error occurs
* @exception 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</code>
* 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 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</code> object.
*
* @param listener a component, usually the connection pool manager,
* that has implemented the
* <code>ConnectionEventListener</code> 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</code> object.
*
* @param listener a component, usually the connection pool manager,
* that has implemented the
* <code>ConnectionEventListener</code> interface and
* been registered with this <code>PooledConnection</code> object as
* a listener
* @see #addConnectionEventListener
*/
void removeConnectionEventListener(ConnectionEventListener listener);
/**
* Registers a <code>StatementEventListener</code> with this <code>PooledConnection</code> object. Components that
* wish to be notified when <code>PreparedStatement</code>s created by the
* connection are closed or are detected to be invalid may use this method
* to register a <code>StatementEventListener</code> with this <code>PooledConnection</code> object.
* <p>
* @param listener an component which implements the <code>StatementEventListener</code>
* interface that is to be registered with this <code>PooledConnection</code> object
* <p>
* @since 1.6
*/
public void addStatementEventListener(StatementEventListener listener);
/**
* Removes the specified <code>StatementEventListener</code> from the list of
* components that will be notified when the driver detects that a
* <code>PreparedStatement</code> has been closed or is invalid.
* <p>
* @param listener the component which implements the
* <code>StatementEventListener</code> interface that was previously
* registered with this <code>PooledConnection</code> object
* <p>
* @since 1.6
*/
public void removeStatementEventListener(StatementEventListener listener);
}
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