Re: Customize toString() for arrays...?

From:
Tom Anderson <twic@urchin.earth.li>
Newsgroups:
comp.lang.java.programmer
Date:
Sun, 25 Jul 2010 17:09:02 +0100
Message-ID:
<alpine.DEB.1.10.1007251634150.18933@urchin.earth.li>
On Fri, 23 Jul 2010, markspace wrote:

Tom Anderson wrote:

Yes, in this case, you are largely stuffed. UNLESS you pay heed to my
super-wily suggestion:

...

This only works with arrays of objects, but you could write a family of
specialised versions for arrays of primitives, and create the appropriate
one in the getter.


I thought my autoBox() method was more wily, because it dealt with
primitives.


You deal with primitives, but not nested lists, which is where i was
applying wiliness. We are disjointly wily. But we can unionise: in my
wrapper, change the type of the array instance variable to Object, and
rewrite the getter to use your reflective approach:

Object object = Array.get(array, index);
if (obj.getClass().isArray()) object = new ArrayWrapper(object);
return object;

Now we have something that handles primitives and nested lists, and does
so with minimal allocation (just small wrapper objects, never arrays), and
doesn't require a type parameter to be passed in.

It's not as generally useful as your unbox method could be, because it
isn't typesafe, but it will do for toString.

tom

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