Re: JDO 2.1 specification draft can be reviewed...

[Craig L Russell]

I've added this to the latest draft of the specification dated 2007-09-28.

8.6 State Interrogation
public static ObjectState getObjectState(Object pc);

8.6.1 enum ObjectState
public enum ObjectState {
        TRANSIENT("transient"),
        TRANSIENT_CLEAN("transient-clean"),
        TRANSIENT_DIRTY("transient-dirty"),
        PERSISTENT_NEW("persistent-new"),

        PERSISTENT_NONTRANSACTIONAL_DIRTY("persistent-nontransactional-dirty"),
        PERSISTENT_CLEAN("persistent-clean"),
        PERSISTENT_DIRTY("persistent-dirty"),
        PERSISTENT_DELETED("persistent-deleted"),
        PERSISTENT_NEW_DELETED("persistent-new-deleted"),
        DETACHED_CLEAN("detached-clean"),
        DETACHED_DIRTY("detached-dirty");
}

Craig

On Aug 4, 2007, at 6:14 PM, cbeams wrote:

This method returns an enum representing the life cycle state of the parameter instance. The enum has an overloaded toString method that returns the life cycle state as discussed in section 5.5. HOLLOW_PERSISTENT_NONTRANSACTIONAL("hollow/persistent- nontransactional"),

Craig, all,





        String getObjectState(Object pc)



        assert pc.isDetached() && pc.isDirty();





or, just as easily:

        assert "detached-dirty".equals(JPOXJDOHelper.getObjectState(pc));





        package javax.jdo;
        public interface JDOHelper {
                // ...
                ObjectState getObjectState(Object pc);
        }

Where ObjectState is defined as:

        package javax.jdo;
        public enum ObjectState {
                TRANSIENT,
                TRANSIENT_CLEAN,
                TRANSIENT_DIRTY,
                PERSISTENT_NEW,
                PERSISTENT_NONTRANSACTIONAL,
                PERSISTENT_NONTRANSACTIONAL_DIRTY,
                PERSISTENT_CLEAN,
                PERSISTENT_DIRTY,
                HOLLOW,
                PERSISTENT_DELETED,
                PERSISTENT_NEW_DELETED,
                DETACHED_CLEAN,
                DETACHED_DIRTY;
        }



        assert JDOHelper.getObjectState(pc) == ObjectState.DETACHED_DIRTY;








Thanks for considering,

- Chris Beams

This isn't so much a comment on the 2.1 spec changes, but rather a suggestion for an addition to the JDOHelper interface in the 2.1 timeline (I don't know if it's too late for this sort of thing)... JPOX's JPOXJDOHelper implementation exposes a very useful method with the following signature: I would love to see this method exposed by the standard JDOHelper interface. The spec currently provides status interrogation methods (per section 8.5), but they're primarily useful assuming one is testing for a particular state. For example, I might care to assert that a pc is 'detached-dirty': That's not so bad; it's even elegant. But if I'm debugging my way through an application, there's no standardized way (that I know of) to simply print out the state of the pc object. Using JPOX internals, I can do the following: logger.debug(JPOXJDOHelper.getObjectState(pc)); // prints out 'detached-dirty', 'transient-clean', or whatever the state actually is. This method is most useful from a practical point of view: debugging. One might argue that such code need not be portable and thus standardized, but I'd counter with "why not"? State transitions in JDO are complex enough; if we can make the standard interface for interrogation of those states friendlier, all the better. IMHO, the only problem with the current JPOX getObjectState() implementation is that it's string-based. If this method were to be considered for the 2.1 JDOHelper interface, I would suggest that the return type be an enumeration that contains identifiers for all the object states, optional and required: With this addition in place, the user gets the best of both worlds. Asserting for a given state is trivially easy: And determining object state with no a priori knowledge is simple, too: logger.debug(JDOHelper.getObjectState(pc)); // prints out "DETACHED_DIRTY" The ObjectState enum could also override toString() such that it transforms the all-caps-and-underscores identifier to the lower- case-and-dashes format used within the spec, e.g.: DETACHED_DIRTY.toString() returns "detached-dirty"

From: Craig L Russell <[EMAIL PROTECTED]>
Date: August 3, 2007 7:04:52 PM PDT

Subject: JDO 2.1 specification draft can be reviewed...


at http://db.apache.org/jdo/documentation.html

Check it out, and send comments...

Craig Russell

To: Apache JDO project <jdo-dev@db.apache.org>, JDO Expert Group <[EMAIL PROTECTED]> Architect, Sun Java Enterprise System http://java.sun.com/products/ jdo

408 276-5638 mailto:[EMAIL PROTECTED]
P.S. A good JDO? O, Gasp!

Craig Russell
Architect, Sun Java Enterprise System http://java.sun.com/products/jdo
408 276-5638 mailto:[EMAIL PROTECTED]
P.S. A good JDO? O, Gasp!

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