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.
*
* An application programmer does not use the PooledConnection
* interface directly; rather, it is used by a middle tier infrastructure
* that manages the pooling of connections.
*
* When an application calls the method DataSource.getConnection,
* it gets back a Connection object. If connection pooling is
* being done, that Connection object is actually a handle to
* a PooledConnection object, which is a physical connection.
*
* The connection pool manager, typically the application server, maintains
* a pool of PooledConnection objects. If there is a
* PooledConnection object available in the pool, the
* connection pool manager returns a Connection object that
* is a handle to that physical connection.
* If no PooledConnection object is available, the
* connection pool manager calls the ConnectionPoolDataSource
* method getPoolConnection to create a new physical connection. The
* JDBC driver implementing ConnectionPoolDataSource creates a
* new PooledConnection object and returns a handle to it.
*
* When an application closes a connection, it calls the Connection
* method close. When connection pooling is being done,
* the connection pool manager is notified because it has registered itself as
* a ConnectionEventListener object using the
* ConnectionPool method addConnectionEventListener.
* The connection pool manager deactivates the handle to
* the PooledConnection object and returns the
* 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.
*
* The physical connection is not closed until the connection pool manager
* calls the 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.
*
*
* A connection pool manager is often also a statement pool manager, maintining
* a pool of PreparedStatement objects.
* When an application closes a prepared statement, it calls the
* PreparedStatement
* method close. When Statement pooling is being done,
* the pool manager is notified because it has registered itself as
* a StatementEventListener object using the
* ConnectionPool method addStatementEventListener.
* Thus, when an application closes its PreparedStatement,
* the underlying prepared statement is recycled rather than being closed.
*
*
* @since 1.4
*/
public interface PooledConnection {
/**
* Creates and returns a Connection object that is a handle
* for the physical connection that
* this PooledConnection object represents.
* The connection pool manager calls this method when an application has
* called the method DataSource.getConnection and there are
* no PooledConnection objects available. See the
* {@link PooledConnection interface description} for more information.
*
* @return a Connection object that is a handle to
* this 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 PooledConnection
* object represents. An application never calls this method directly;
* it is called by the connection pool module, or manager.
*
* 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 PooledConnection object.
*
* @param listener a component, usually the connection pool manager,
* that has implemented the
* 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
* PooledConnection object.
*
* @param listener a component, usually the connection pool manager,
* that has implemented the
* ConnectionEventListener interface and
* been registered with this PooledConnection object as
* a listener
* @see #addConnectionEventListener
*/
void removeConnectionEventListener(ConnectionEventListener listener);
/**
* Registers a StatementEventListener with this PooledConnection object. Components that
* wish to be notified when PreparedStatements created by the
* connection are closed or are detected to be invalid may use this method
* to register a StatementEventListener with this PooledConnection object.
*
* @param listener an component which implements the StatementEventListener
* interface that is to be registered with this PooledConnection object
*
* @since 1.6
*/
public void addStatementEventListener(StatementEventListener listener);
/**
* Removes the specified StatementEventListener from the list of
* components that will be notified when the driver detects that a
* PreparedStatement has been closed or is invalid.
*
* @param listener the component which implements the
* StatementEventListener interface that was previously
* registered with this PooledConnection object
*
* @since 1.6 */ public void removeStatementEventListener(StatementEventListener listener); }