🚀 go-pugleaf

On Wed, 27 Jan 1999 22:44:07 GMT, info@nbinc.com (info@nbinc.com)
wrote:

>1. When looking at java code, one sees many statements like:
>	xclass xobject=new xclass()
>isnt this use of the first "xclass" redundant? the new object HAS to
>be of the type xclass, so why were the purposes of instantiation &
>declaration separated?

This is a combination of two separate things, a declaration:

 xclass xobject; // declares xobject to be a variable of type xclass

and an initialization:

 xobject = new xclass(); // creates a new instance of xclass

This example shows why it's not redundant:

 Window w = new Dialog(parent);

That is, a variable of type X can point to an instance of class X, but
it can alternatively point to an instance of a descendant class.

>2. why cant properties of components be accessed directly eg cant say:
>	buttonControl1.Label="some text"
>have to say:
>	buttonControl1.setLabel("some text")

Because Java isn't Delphi. :) In languages like Delphi and Visual
Basic, an attempt to set a property:

 MyButton.Caption := 'Some text';

actually causes the invocation of a method (SetCaption in this case).
The only difference with Java is that this method invocation is
explicit, and doesn't happen magically behind the scenes.

-Steve