Re: Instantiate an abstract class

From:
Rob McDonald <rob.a.mcdonald@gmail.com>
Newsgroups:
comp.lang.java.help
Date:
Tue, 5 Apr 2011 14:54:04 -0700 (PDT)
Message-ID:
<edce4c55-5560-4718-b3b2-d9797dff79fc@l39g2000yqh.googlegroups.com>
On Apr 5, 5:48 pm, Joshua Cranmer <Pidgeo...@verizon.invalid> wrote:

On 04/05/2011 05:14 PM, Rob McDonald wrote:

Now, we all know that you can't instantiate an abstract class -- but I
want to anyway... Actually, I would like my abstract class to be abl=

e

to instantiate another instance of whatever concrete class it is at
the time.


Your class is abstract, so you can easily have:

abstract class AFoo {
   public abstract AFoo makeInstance();

}

Or, as Patricia mentions:

abstract class AFoo {
   public abstract AFoo clone(); // Legal only in Java 5+

}

Each subclass would then implement this method as appropriate.

I can answer your question more directly with reflection, but it's a
method I wouldn't recommend without a very compelling reason why this
approach wouldn't work for you.


Joshua,

That worked great. I don't know why I hadn't come up with that
solution myself.

Most of my online searches had lead down the reflection path and I
quickly got myself wrapped around the axle. I'm going to go with the
above implementation, but I am curious about how it could be made to
work the other way.

Thanks for the help,

Rob

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