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AbstractValueModel
Hi,
today i run in following problem with the AbstractValueModel:
Code:
ValueHolder valueHolder = new ValueHolder(new Object());
valueHolder.set( new Object());
this code will throw a NullPointerException because the method set(Object o) calls fireValueChanged() and the used listeners List is not instanciated. The List member is only instanciated if a ValueListener is registered.
Code:
[ERROR] ApplicationAdvisor - null <java.lang.NullPointerException>java.lang.NullPointerException
at org.springframework.rules.values.AbstractValueModel.fireValueChanged(AbstractValueModel.java:63)
at org.springframework.rules.values.ValueHolder.set(ValueHolder.java:40)
For the listeners i would sugest an eager instanciation, but I checked the CVS History and it was eager until the check in on 18.08.04!
Now, why it was changes to "lazy"? And what is the best solution to this problem?
- Back to eager instanciation?
- Check if not null on fireValueChanged?
- ...
siu
Claudio
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Indeed a bug. I still think lazy is what we want, as there can be a lot of these value model objects, and potentially some without value listeners. Will fix promptly.
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Well, maybe that case isn't so common after all, as otherwise my tests would've caught it. Hmm... I guess in generally I've been favoring lazy instantiation where possible in a Swing environment to help get the best possible performance.
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Keith,
in general i like the eager instanciation, because it is more "bug-save".
But in this case, i'm with you as there can be alot of ValueModel without listeners!
Thanks for the quick reply
Claudio