An adapter for a target DataSource, applying the current
Spring transaction's isolation level (and potentially specified user credentials)
to every getConnection call. Also applies the read-only flag,
Can be used to proxy a target JNDI DataSource that does not have the
desired isolation level (and user credentials) configured. Client code
can work with this DataSource as usual, not worrying about such settings.
WARNING: This adapter simply calls
Connection.setReadOnly(boolean) for every Connection obtained from it.
It does, however, not reset those settings; it rather expects the target
DataSource to perform such resetting as part of its connection pool handling.
Make sure that the target DataSource properly cleans up such transaction state.