Re: errors in Hashtable to HashMap

On May 2, 12:58=A0pm, "Matt Humphrey" <ma...@[EMAIL PROTECTED]
> wrote:
> "bH" <bherbs...@[EMAIL PROTECTED]
> wrote in message
>
>
news:2a2e1dbf-fcdc-49ed-88c0-ec7025e07ca4@[EMAIL PROTECTED]
> On May 2, 10:33 am, Roedy Green <see_webs...@[EMAIL PROTECTED]
>
> wrote:
>
> > On Fri, 2 May 2008 05:34:40 -0700 (PDT), bH <bherbs...@[EMAIL PROTECTED]
>
> > wrote, quoted or indirectly quoted someone who said :
>
> > >Exception in thread "AWT-EventQueue-2" java.lang.NullPointerException
> > > at TestPhneDialer.action(TestPhneDialer.java:30)
>
> > Since the listing you post has no line numbers, we can't easily tell
> > what that is pointing to. Add a comment to point it out.
> > --
>
> > Roedy Green Canadian Mind Products
> > The Java Glossaryhttp://mindprod.com
> > Hi Matt,
> > The suggestions that you made do not fix the situation :(
>
> Perhaps you have more than one error. =A0Exactly what did you do and
what
> error is it producing? =A0Are you sure the browser isn't caching your
appl=
et?
> You are definately declaring the variable twice.
>
> > This is the line 30 that is in error:
> > String name =3D new
> > String((String)buttonSoundNames.get((Button)e.target));
>
> > P.S. I think that this error happens because the buttonSoundNames is
> > .not
> > available at this line(not readable at this point in the program).
> > But that is just my dumb guess.
>
> You know (and can test) that buttonSoundNames is null at this point.
=A0No=
w
> work backwards and ask yourself what conditions are needed in order for
it=

> to be null. Perhaps init() is not called, the initialization is
shadowed,
> the applet has been cached, etc. =A0Then test each of these hypotheses.
>
> Also, it's not meaningful for the HashMap loadfactor to be > 1.
> Essentially, you're saying that when a table of size 3 contains more
than =
9
> elements it should be resized.
>
> Matt Humphreyhttp://www.iviz.com/

Hi Matt,

Thanks for your response. Your suggestions are really
appreciated. I have corrected the code so that errors
re****ted earlier no longer exist.

The major correction happened in the declaration
early in the program.

The following is offered as a solution.

im****t java.applet.*;
im****t java.awt.*;
im****t java.util.HashMap;

@[EMAIL PROTECTED]
( "unchecked" )

public class HMapTestPhneDialer extends Applet {

  boolean DEBUG =3D false;
  HashMap buttonSoundNames;
  KeyPad keyPad;

  public void init() {
    keyPad =3D new KeyPad();
    buttonSoundNames =3D new HashMap<Button,String>();
    // changed this

    buttonSoundNames.put(keyPad.b1, "1.au");
    buttonSoundNames.put(keyPad.b2, "2.au");
    buttonSoundNames.put(keyPad.b3, "3.au");
    setLayout(new FlowLayout());
    add(keyPad);
    validate();
    System.out.println(keyPad.b3);
  }

  public boolean action(Event e, Object arg) {
            //System.out.println("Here");
        if (e.target instanceof Button) {
            String name =3D
new String((String)buttonSoundNames.get((Button)e.target));
            System.out.println(name);
            //results should show "1.au" or"2.au" or "3.au"
            //depending which button press
      return true;
    }
    return false;
  }
}
class KeyPad extends Panel {
  Button b1,b2,b3;
  KeyPad() {
    b1 =3D new Button("1");
    b2 =3D new Button("2");
    b3 =3D new Button("3");
    setLayout(new GridLayout(4,3,10,10));
    add(b1);
    add(b2);
    add(b3);
  }
}
Thanks again,

bH