[
http://issues.apache.org/jira/browse/COLLECTIONS-110?page=comments#action_12425847
]
Dusan Chromy commented on COLLECTIONS-110:
------------------------------------------
My another argument for generics - and also an idea for improvement in
collections.sf.net - would be to make
the functors work with checked exceptions.
Without generics, you have to wrap any checked exception in a FunctorException
and unwrap it later, which sort of steals all the benefits of an algorithm over
a loop.
Consider this example:
<code>
public deleteBulk(List l) throws AppException {
try {
CollectionUtils.forAllDo(l, new Closure() {
public void execute(Object arg) {
try {
deleteAppObj((AppType)arg); //can throw
AppException
} catch (AppException e) {
throw new FunctorException(e);
}
}
});
} catch (FunctorException fe) {
throw (AppException)fe.getCause();
}
}
</code>
Now in Java 5 we can make our functors exception-savvy:
<code>
interface ThrowingClosure<T,E extends Exception> {
void execute(T arg) throws E;
}
interface Closure<T> extends ThrowingClosure<T,RuntimeException> {}
</code>
With such functors you can rewrite the code from the above example so:
<code>
public deleteBulk(List l) throws AppException {
CollectionUtils.forAllDo(l, new ThrowingClosure<AppType,AppException>()
{
public void execute(AppType arg) throws AppException {
deleteAppObj(arg); //can throw AppException
}
});
}
</code>
As you can see, the latter code is not cluttered with exception handling. Thats
Apache Collections I'd like to have for my Java 5 projects!
> Support parametized classes with commons.collections.
> -----------------------------------------------------
>
> Key: COLLECTIONS-110
> URL: http://issues.apache.org/jira/browse/COLLECTIONS-110
> Project: Commons Collections
> Issue Type: Wish
> Environment: Operating System: other
> Platform: Other
> Reporter: Colbert Philippe
>
> It's time to create a parallel version of commons.collections to support
> parametized classes of each container class and abstract class. It's not
> that
> hard. There is a 23 PDF document on Sun Java website describing in detail
> how
> it should be done and what to watch out for.
> I already converted a few classes from commons.collection privately for my
> own
> needs. Once you get the hang of it, it's a rather quick process.
> I am even willing to volunteer my time to do some more but I need the
> collaboration of some of the original programmers to watch over things.
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