| This interceptor binds a new JDO PersistenceManager to the thread before a method
call, closing and removing it afterwards in case of any method outcome.
If there already is a pre-bound PersistenceManager (e.g. from JdoTransactionManager,
or from a surrounding JDO-intercepted method), the interceptor simply participates in it.
Application code must retrieve a JDO PersistenceManager via the
PersistenceManagerFactoryUtils.getPersistenceManager method,
to be able to detect a thread-bound PersistenceManager. It is preferable to use
getPersistenceManager with allowCreate=false, if the code relies on
the interceptor to provide proper PersistenceManager handling. Typically, the code
will look like as follows:
public void doSomeDataAccessAction() {
PersistenceManager pm = PersistenceManagerFactoryUtils.getPersistenceManager(this.pmf, false);
...
}
Note that this interceptor automatically translates JDOExceptions, via
delegating to the PersistenceManagerFactoryUtils.convertJdoAccessException
method that converts them to exceptions that are compatible with the
org.springframework.dao exception hierarchy (like JdoTemplate does).
This can be turned off if the raw exceptions are preferred.
This class can be considered a declarative alternative to JdoTemplate's
callback approach. The advantages are:
- no anonymous classes necessary for callback implementations;
- the possibility to throw any application exceptions from within data access code.
The drawback is the dependency on interceptor configuration. However, note
that this interceptor is usually not necessary in scenarios where the
data access code always executes within transactions. A transaction will always
have a thread-bound PersistenceManager in the first place, so adding this interceptor
to the configuration just adds value when fine-tuning PersistenceManager settings
like the flush mode - or when relying on exception translation.
author:
Juergen Hoeller
since:
13.06.2003
See Also: PersistenceManagerFactoryUtils.getPersistenceManager
See Also: JdoTransactionManager
See Also: JdoTemplate | 