negated boolean

[Peter Gragert]

Nitpicking myself page http://www.javaranch.com/CodeBarn/BarnLoadGifMsg.jsp

<snip>
    public void paint( Graphics g ) 
    {
        // test a boolean to if the "loading" message should be displayed
        if ( !showWaitMsg )
//Peter: switch the if else part no ! needed
        {
            g.drawImage( theHorse , 25 , 25 , this );
            g.drawImage( theMoose , 25 , 130 , this );
        }
        else
        {
            g.drawString( "Please wait... loading..." , 20 , 20 );
            loadGraphics(); // call the method that actually loads the graphics
        } 
    } // close paint
<snip>

;-)
[Marilyn added code tags]

[This message has been edited by Marilyn deQueiroz (edited February 23, 2001).]

[Johannes de Jong]

Why would (should) you avoid using the ! (not)

[Peter Gragert]

I used this construction in one of my solutions and
was advised to not use !boolean.
Peter

[Joe Von]

I believe that the motivation behind avoiding the negated boolean is simply readablity.
It is simpler and more understandable to reverse the if / else statement. A future reader will have an easier time with an
"if TRUE" than with an "if not TRUE" construction.
Of course, the functionality is the same both ways, but you always want to assume that sometime in the future some drooling moron will need to understand and modify your code. And you should try and help the poor benighted sod.

[paul wheaton]

We will make the change to the code. Good catch!

[Marilyn de Queiroz]

Thanks, Peter. It's changed.

[Peter Gragert]

Suggestion of my son:
If the then part is very long and the else part is short
it may be meaningful to use a negated boolean, because
one can see this 'easy' agaist 'difficult' part with just
opening your eyes.
Comments?

[paul wheaton]

Then the if part needs to be in a seperate method.