Re: Casting a Generic List

From:
"Ingo R. Homann" <ihomann_spam@web.de>
Newsgroups:
comp.lang.java.programmer
Date:
Thu, 26 Apr 2007 17:24:43 +0200
Message-ID:
<4630c43b$0$20293$9b4e6d93@newsspool3.arcor-online.net>
HI,

Bryan wrote:

Hello all,

Is it possible to cast an entire Generic List somehow? For example,
say I have the following:

public interface Foo {
    .....
}

public class Bar implements Foo {
    ....
}

public class Test {
    public List<Foo> getFooList() { .... }

    public static void main(String[] args) {
        Test test = new Test();

        List<Bar> bars = test.getFooList(); // illegal
    }
}

Now assume that all the objects in the FooList were indeed
instantiated as Bar objects.

I get a compile error saying it can't convert from List<Foo> to
List<Bar>. I could always just get a list of Foo objects and cast
them to Bars myself, but I'm just wondering if it can be done for me
all at once.

Any suggestions?


Not every Foo is a Bar, so of course such an assignment (or even a cast)
is impossible. (Note that for a similar (but slightly more difficult)
reason the opposite cast is impossible as well.)

Ciao,
Ingo

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