Re: cast to sub-class or extending instance of super or a.n.other

From:
"Richard Maher" <maher_rj@hotspamnotmail.com>
Newsgroups:
comp.lang.java.programmer
Date:
Mon, 13 Apr 2009 08:21:21 +0800
Message-ID:
<gru0gj$fi4$1@news-01.bur.connect.com.au>
Hi Mike,

"Mike Schilling" <mscottschilling@hotmail.com> wrote in message
news:kDhEl.26829$YU2.25763@nlpi066.nbdc.sbc.com...

Richard Maher wrote:

Hi Peter,

Thanks for the reply.

"Peter Duniho" <NpOeStPeAdM@nnowslpianmk.com> wrote in message
news:op.ur83gavi8jd0ej@macbook-pro.local...

On Sat, 11 Apr 2009 18:10:45 -0700, Richard Maher
<maher_rj@hotspamnotmail.com> wrote:

[...]
As I said this has gotta be easier than this so please put me out
of my misery. What's the best way of "new O = instance of A +
stuff. Then still behave like A in Arrays/Collections) Or is there
something more appropriate
than ArrayList?


Hard to say without knowing exactly what you're trying to do.


Ok, cards on the table: - I have an instance of JSObject; I want to
attach an integer to it (oh, but we must know exactly what that
integer does!) Alright, it's a MinimumMessageNumber; any messages
less than this will be ignored. I want to reference the resultant
object/structure by "index" for performance. The ArrayList (I'm
happy
for alternatives and I'm looking at your hashCode) will normally
contain 1 element, and max-out at about10. The minMsgNum is an
appendage/baggage something that I'm sure there's a flash OO term
for
like "orthogonal" that'll give everyone a boner (see, I've been
drinking :-)


Turn things around: create a MessageObject that contains two fields:

1. You minimum message number
2. A reference to your JSObject
MessageObject can also delegate some methods to the JSObject, if
that's convenient.

Make your ArrayList a List or MessageObjects.

If you need them sorted, use a TreeSet instead of an ArrayList and
define MessageObject.compareTo() appopriately.


That's where I got to so far (See below). I'm not totally happy with it for
reasons discussed previously with Peter.

Cheers Richard Maher

    public class WindowSlot
    {
       public JSObject window;
       public int minMsgNum;

       WindowSlot(JSObject window)
       {
           this.window = window;
           this.minMsgNum = getMsgSeqNum();
       }

       public JSObject getWindow() {
           return this.window;
       }

       public int getMinMsg() {
           return this.minMsgNum;
       }

       public boolean equals(Object o) {
           if (o instanceof WindowSlot)
                return window.equals(((WindowSlot)o).getWindow());
           else
               if (o instanceof JSObject)
                   return window.equals((JSObject)o);
               else
                   return false;
       }

       public int hashCode() {
           return window.hashCode();
       }
    }

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