On 8/31/2010 10:03 AM, a wrote:
The point for doing this is to limit the options for the user to input
when
calling the method.
It is very similiar to HasHorizontalAlignment and
HasHorizontalAlignment.HorizontalAlignment, but I dont understand how it
works.
They really don't work.
SwingConstants just holds a bunch of ints. You example just uses
Strings. Neither one of these by their nature actually limits the
options for user of the method. It was a dumb idea for Swing to do
things this way.
It's better to use a specific type that you created to limit the options
for the user of the method.
public class MyOptions {
public static final MyOption OPTION1 = new MyOption( "Option 1" );
public static final MyOption OPTION2 = new MyOption( "Option 2" );
private final String option;
private MyOption( String s ) {
option = s;
}
public String toString() {
return option;
}
}
is the basic pattern. Note the public (but final) static fields and the
private constructor. Those are key. Enums will do some of this
auto-magically for you.
Now you can restrict a method parameter to just OPTION1 or OPTION2.
public void someMethod( MyOptions opt ) {
...
}
Since only you have control of your type MyOptions class, only you can
add more fields for a user to pass to someMethod().
//...