Re: Construct a superclass as itself

From:

=?ISO-8859-2?Q?Marcin_Rze=BCnicki?= <marcin.rzeznicki@gmail.com>

Newsgroups:

comp.lang.java.programmer

Date:

Sun, 15 Nov 2009 06:14:36 -0800 (PST)

Message-ID:

<27803914-6810-4f7c-9db4-f819564b2cda@d5g2000yqm.googlegroups.com>

On 15 Lis, 13:51, The87Boy <the87...@gmail.com> wrote:

I am trying to construct a superclass as itself like this:

    public Parent(Parent parent) {

        // Set this class as itself
        this = parent;
    }

But it is not allowed by the compiler, but do I have to set all
variables like this:

    public Parent(Parent parent) {

        // Set this class as itself
        this.id = parent.getID();
        this.cclass = parent.getCClass();
    }

Or are there any easier way?

Not really. Depending on your needs you might try to implement
Clonable and clone parent, but still you will have to decide how to
treat reference fields (clone is shallow). Probably, you will end up
cloning all references as well so no real savings in typing here.
Additional casts can also be cumbersome. Cloning is also incompatible
with final fields. Another trick is to serialize parent and recreate
(deserialize) your object from the resulting stream, but personally I
find that ugly. So I'd just leave it as you've done it.