Re: forEach and Casting

From:

Piotr Kobzda <pikob@gazeta.pl>

Newsgroups:

comp.lang.java.programmer

Date:

Sun, 22 Apr 2007 21:16:07 +0200

Message-ID:

<f0gca1$lo9$1@inews.gazeta.pl>

Jason Cavett wrote:

I decided to go with something like this:

ArrayList<Specific> var = (ArrayList<Specific>)
getDirectDescendentsOfType(Class classType)

And my getDirectDescendentsOfType is defined as...

public ArrayList<? extends Generic> getDirectDescendentsOfType(Class
classType) {
// stuff
}

It works well. The only downside is I get a warning every time I
perform the cast above. So, I have to add @SuppressWarnings statement
to methods that have this within them. Not a major thing, just
somewhat of a pain.

(I'm going to stick with this method unless anybody has any other
suggestions.)

See my previous post in this thread. Generic method declared as there
will prevent you from suppressing this warning.

It also allows for a type-safe implementation of that method itself:

     List<E> list = new ArrayList<E>();
     // traverse tree descendants, and for each do that...
     if (type.isInstance(element)) {
         list.add(type.cast(entry));
     }
     ...
     return list;

piotr