Dear Derby users,
Please read this message if you work on an application server or in an
application layer which cares about distributed transactions and/or
pooled connections.
Right now the inheritance graph for Derby's DataSources does not mirror
the corresponding graph of interfaces in javax.sql. Derby's DataSources
are classes which you will find in Derby's published javadoc for the
package org.apache.derby.jdbc. In particular, Derby's XADataSources and
ConnectionPoolDataSources implement the DataSource interface. This is so
even though the javax.sql.XADataSource and
javax.sql.ConnectionPoolDataSource interfaces themselves do not extend
javax.sql.DataSource.
We believe this is confusing, particularly to developers who are trying
to build applications which easily port across different vendors' JDBC
implementations. We propose to rework the hierarchy of classes in
org.apache.derby.jdbc so that our XADataSources and
ConnectionPoolDataSources no longer implement javax.sql.DataSource. We
propose to expose this change in Derby 10.2.
However, we do not want to make this change if it will break existing
applications. Please let us know if you think this will break your app
server or other Derby-powered application.
Thanks,
-Rick
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Here is a bit more detail on the problem. This is the inheritance graph
from javax.sql:
CommonDataSource
/ | \
XADataSource DataSource ConnectionPoolDataSource
Here is the corresponding 10.1 graph from org.apache.derby.jdbc:
ClientDataSource
/ \
ClientXADataSource ClientConnectionPoolDataSource
We propose the following 10.2 graph for org.apache.derby.jdbc
ClientBaseDataSource
/ | \
ClientXADataSource ClientDataSource ClientConnectionPoolDataSource
