PooledConnection (Java 2 Platform SE 5.0) (original) (raw)

javax.sql

Interface PooledConnection

All Known Subinterfaces:

public interface PooledConnection

An object that provides hooks for connection pool management. A 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 aPooledConnection 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 PooledConnection method getConnection to create a new physical connection 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.

Since:

1.4

Method Summary
void	addConnectionEventListener(ConnectionEventListener listener) Registers the given event listener so that it will be notified when an event occurs on this PooledConnection object.
void	close() Closes the physical connection that this PooledConnection object represents.
Connection	getConnection() Creates and returns a Connection object that is a handle for the physical connection that this PooledConnection object represents.
void	removeConnectionEventListener(ConnectionEventListener listener) Removes the given event listener from the list of components that will be notified when an event occurs on thisPooledConnection object.

Method Detail

getConnection

Connection getConnection() throws SQLException

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 theinterface description for more information.

Returns:

a Connection object that is a handle to this PooledConnection object

Throws:

[SQLException](../../java/sql/SQLException.html "class in java.sql") - if a database access error occurs

close

void close() 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 interface description for more information.

Throws:

[SQLException](../../java/sql/SQLException.html "class in java.sql") - if a database access error occurs

addConnectionEventListener

void addConnectionEventListener(ConnectionEventListener listener)

Registers the given event listener so that it will be notified when an event occurs on this PooledConnection object.

Parameters:

listener - a component, usually the connection pool manager, that has implemented theConnectionEventListener interface and wants to be notified when the connection is closed or has an error

removeConnectionEventListener

void removeConnectionEventListener(ConnectionEventListener listener)

Removes the given event listener from the list of components that will be notified when an event occurs on thisPooledConnection object.

Parameters:

listener - a component, usually the connection pool manager, that has implemented theConnectionEventListener interface and been registered with this PooledConnection object as a listener

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For further API reference and developer documentation, see Java 2 SDK SE Developer Documentation. That documentation contains more detailed, developer-targeted descriptions, with conceptual overviews, definitions of terms, workarounds, and working code examples.