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Message:

Various questions about the JFC

Posted by Nigel Sandever on May 24, 2001 at 8:46 AM

Hi,

Im a long time (20+ yrs) professional prog., but a neophite at java and there are various things regarding the JFC that strick me as suboptimal:)

Maybe there are some opinions out there that will clarify things for me.

1) Why do we have a xxxx = getXxxx(), and a setXxxx( xxxx ) calls...
not xxxx = xxxx() and xxxx( xxxx );

eg. to clarify

class DecimalFormat {
...
void setMultiplier( int newValue ) {...}
int getMultiplier() {...}
}

Why not

class DecimalFormat {
...
int multiplier( int newValue ) {...} // (1)
int multiplier() {...}
}

Note: That the "set" method also returns the value set. This has the effect of allow one to "chain" method calls.
----------------------------------------------------------------

2) Why dont methods that modify the state of an object also return the modified object (reference)???

So that instead of coding...

void paint( Graphics g ) {
Graphics2D g2 = (Graphics2D)g;
AffineTransform tx = g2.getTransform().translate( w/2, h/2 );
g2.setTransform( tx );
...
)

you could code:

void paint( Graphics g ) {
Graphics2D g2 = (Graphics2D)g;
g2.setTransform( g2.getTransform().translate( w/2, h/2 ) );
...
)

Which (to me) clarifies the code and "saves" and intermediate variable.

Is there some OO reason for not doing this....I notice that it does happen some places like

Color color2 = color.darker();

though in this instance I'd prefer it if the darker() method returned a darker version of the color WITHOUT modifying the original... Or change the method name to darken() to indicate that it is modifying THIS color not just returning a darker one.

I end up coding stuff like:

...
Color sunlite = somecolor;
Color shade = new Color( sunlite.getRGB() ).darker();
...

When I want to derive another shade of a color and retain the original.

3) Why do they (SUN?) not use more method overiding?

eg.

Class Graphics {
void drawRect( ...); NOT draw( Rectangle );
void drawImage( Image i ....); NOT draw( Image i ... );
void drawString( String s ... ); NOT draw( String s ... );
etc.
}

Sorry for the rambling, Nigel Sandever.

PS. If this system doesn't automatically forward replies to my email, I'd appreciate it if any responders did.... it much easier (for me:) if I dont have to keep coming back and checking...