A factory for connections to the physical data source that this
DataSource object represents. An alternative to the
DriverManager facility, a DataSource object
is the preferred means of getting a connection. An object that implements
the DataSource interface will typically be
registered with a naming service based on the
JavaTM Naming and Directory (JNDI) API.
The DataSource interface is implemented by a driver vendor.
There are three types of implementations:
- Basic implementation -- produces a standard
Connection
object
- Connection pooling implementation -- produces a
Connection
object that will automatically participate in connection pooling. This
implementation works with a middle-tier connection pooling manager.
- Distributed transaction implementation -- produces a
Connection object that may be used for distributed
transactions and almost always participates in connection pooling.
This implementation works with a middle-tier
transaction manager and almost always with a connection
pooling manager.
A DataSource object has properties that can be modified
when necessary. For example, if the data source is moved to a different
server, the property for the server can be changed. The benefit is that
because the data source's properties can be changed, any code accessing
that data source does not need to be changed.
A driver that is accessed via a DataSource object does not
register itself with the DriverManager. Rather, a
DataSource object is retrieved though a lookup operation
and then used to create a Connection object. With a basic
implementation, the connection obtained through a DataSource
object is identical to a connection obtained through the
DriverManager facility. | 