Java 5 rules: Unnecessary casts/Iterators

[dexter riley]

Hello! I was wondering if anyone has been writing rules to take advantage of the new Java 5 types and loop syntaxes? For example, I would like a rule to test for unnecessary casts when using typed collections:
List<Double> list = new ArrayList<Double>();
...
Double d = (Double) list.get(0); //The cast is unnecessary on this typed array.

Similarly, I'd like to find Iterators that are only used to iterate through a collection, so I can replace them with the simpler Java 5 syntax:

List<Double> list = new ArrayList<Double>();
double sum;
...
Iterator<Double> iter = list.iterator();
while (iter.hasNext()){
Double d = iter.next();
sum += d;
}

//could be replaced with:
for (Double d: list)
sum += d;

I've downloaded the Eclipse PMD plugin, and will try my hand at making rules, but if anyone has made these rules already, it would be a big time saver for me.
Thanks for all your help!
-Ed

[Allan Caplan]

After toying with this rule I found it's too simplistic.

It doesn't see the difference between (Double)list.get and (List)list.clone() (for example)

I think I'll have to expand it a bit to map classes to method names. Does that make sense?

[Tom Copeland]

Hi Ed -

Hm, nope, we don't have those rules yet, although they certainly do sound useful. We do have some rules in the "migrating" rulesets, e.g.:

http://pmd.sourceforge.net/rules/migrating.html

But it'd be great to have more rules specifically for JDK 1.5!

Yours,

Tom
Using PMD? Get the book - http://pmdapplied.com/

[Allan Caplan]

Dexter

I'd started a rule like this - but since we have 0 Java 5 code at work, 0 Java 5 code in PMD I've been procrastinating in checking the code in.

I just checked the rule in as net.sourceforge.pmd.rules.migration.UnnecessaryCast. It's not in any ruleset or anything, if you want, give it a go and let me know how it fares.

I'll try and test it a bit more the next few days and see if I can't fully commit it to cvs by the weekend.