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Re: Novice to Generics Trying to Implement a Generic Priority Queue

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On 4/7/2011 4:03 PM, KevinSimonson wrote:

> How would I implement a heap _without_ being able to declare an array
> of the
> type passed in?


This is a bit of a flaw in Java's generics.  The generic types aren't 
reifiable, so there's actually no type at run time for the JVM to use to 
create the array.  Sometimes you can go around this limitation. 
Sometimes you can't.  Here's the case for when you can't.

@SupressWarnings("unchecked")
   queue = (Da[]) new Object[size];

Don't use SupressWarnings unless you have to, but in this case you have to.


>
> The rest of the compilation errors seem to be referring to my use of
> method
> "compareTo<  Da>()".  Can anyone tell me what I'm doing wrong here?


Comparable is a bit of a weird one.  With out going into details, you 
need "Comparable<? super Da>" on the class declaration to get the type 
right.

I didn't read through the rest of your code, but hopefully this gets you 
pointed in the right direction.

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Novice to Generics Trying to Implement a Generic Priority Queue KevinSimonson <kvnsmnsn@hotmail.com> - 2011-04-07 16:03 -0700
  Re: Novice to Generics Trying to Implement a Generic Priority Queue markspace <-@.> - 2011-04-07 17:32 -0700
    Re: Novice to Generics Trying to Implement a Generic Priority Queue KevinSimonson <kvnsmnsn@hotmail.com> - 2011-04-08 14:55 -0700
      Re: Novice to Generics Trying to Implement a Generic Priority Queue markspace <-@.> - 2011-04-08 15:54 -0700
        Re: Novice to Generics Trying to Implement a Generic Priority Queue Lew <noone@lewscanon.com> - 2011-04-08 20:39 -0400
          Re: Novice to Generics Trying to Implement a Generic Priority Queue Tom Anderson <twic@urchin.earth.li> - 2011-04-09 10:36 +0100
  Re: Novice to Generics Trying to Implement a Generic Priority Queue Roedy Green <see_website@mindprod.com.invalid> - 2011-04-09 05:50 -0700
    Re: Novice to Generics Trying to Implement a Generic Priority Queue KevinSimonson <kvnsmnsn@hotmail.com> - 2011-04-11 08:08 -0700
      Re: Novice to Generics Trying to Implement a Generic Priority Queue markspace <-@.> - 2011-04-11 10:29 -0700
      Re: Novice to Generics Trying to Implement a Generic Priority Queue KevinSimonson <kvnsmnsn@hotmail.com> - 2011-04-11 12:10 -0700
        Re: Novice to Generics Trying to Implement a Generic Priority Queue Daniele Futtorovic <da.futt.news@laposte-dot-net.invalid> - 2011-04-11 21:42 +0200
          Re: Novice to Generics Trying to Implement a Generic Priority Queue Tom Anderson <twic@urchin.earth.li> - 2011-04-11 22:41 +0100
            Re: Novice to Generics Trying to Implement a Generic Priority Queue Daniele Futtorovic <da.futt.news@laposte-dot-net.invalid> - 2011-04-12 01:07 +0200

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