Re: Simple question about Java Methods

From:
Daniel Pitts <newsgroup.spamfilter@virtualinfinity.net>
Newsgroups:
comp.lang.java.programmer
Date:
Mon, 18 Aug 2008 08:43:19 -0700
Message-ID:
<48a9a017$0$32294$7836cce5@newsrazor.net>
Danger_Duck wrote:

In paramaters, can I specify what type of String I want? For example,
can I do something like:

public void method1(static final String s) {
  //do something
}

I suppose my bigger question is how you specify a fixed value without
resorting to Java's ugly implementation of enumarations.

For instance, I want to have a class that will graph functions based
on type, but one of the parameters is "sin, square, sawtooth" etc.

Right now, I have declarators like 'public static final String sin =
"SinWave"; ' at the top of my class, and would like it so that the
constructor only accepts static final strings. Of course, he might use
such strings from different classes to my dismay, but at least I will
filter it out a bit.

So am I able to get more specific about the parameters I want to take
in? My gut feeling is no since the above code looks atrocious, but I
would like to hear how one goes about such things in a simple manner
(again, without enumerations).

You've just said something akin to "I want to pound nails into a board,
but I don't want to use an ugly hammer."

enumerations are not ugly:

public class Grapher {
    public enum WaveType {
       sine, square, sawtooth
    }

    public void graph(WaveType type) { ... }
}

This is faster than dealing with String, and more type-safe as well.
Even better, add a method to each:

public class Grapher {
     public enum WaveType {
       sine {
          public void graph(Grapher target) { target.drawSine(); }
       },
       square {
          public void graph(Grapher target) { target.drawSquare(); }
       },
       sawtooth {
          public void graph(Grapher target) { target.drawSawtooth(); }
       }
       ;
         public abstract void graph(Grapher target);
     }

     public void graph(WaveType type) { type.graph(this); }
}

Now, if you really don't want to use enum (I can't imagine why), you
*can* create your own class WaveType, which emulates enums, but thats
just silly unless you want to give your clients the ability to extend them.

So, now having given you what I think is best, can you tell me why you
want to avoid enums? What about this is ugly to you?

Good luck,
Daniel.

--
Daniel Pitts' Tech Blog: <http://virtualinfinity.net/wordpress/>

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