Seems reasonable to me. Especially since commitChanges is a no-op in that
situation.
Also, that's how property change listeners in java beans work... only fire if
the old and new values are different (see
http://download.oracle.com/javase/7/docs/api/java/beans/PropertyChangeSupport.html#firePropertyChange(java.beans.PropertyChangeEvent).
Not that these are property change listeners... but it meets prior
expectation.
Robert
On Mar 11, 2011, at 3/112:22 PM , Michael Gentry wrote:
> I just did a quick test using:
>
> DataContext dataContext = DataContext.createDataContext();
>
> User user = dataContext.newObject(User.class);
>
> user.setFirstName("System");
> user.setLastName("Administrator");
> user.setUsername("admin");
>
> dataContext.commitChanges();
>
> user.setFirstName("System"); // This isn't a real change
>
> System.out.println(dataContext.hasChanges());
>
> dataContext.commitChanges();
>
> In a nutshell, create a user, commit it, set a value to the same
> value, then check hasChanges(). The output is:
>
>
> INFO: INSERT INTO Users (first_name, id, last_name, password,
> username) VALUES (?, ?, ?, ?, ?)
> INFO: [bind: 1->first_name:'System', 2->id:200,
> 3->last_name:'Administrator', 4->password:NULL, 5->username:'admin']
> true
>
> The "true" is that the dataContext has changes, even though the second
> commitChanges() doesn't do anything (there are no real changes).
> Should we modify CayenneDataObject's writeProperty() to check if the
> old value and new value are equal before calling propertyChanged()? I
> was also noticing Embeddables doing something similar.
>
> Thanks,
>
> mrg
