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From: James Kuyper <jameskuyper@verizon.net>
Newsgroups: comp.lang.c,comp.lang.java.programmer
Subject: Re: Self-updating relationship
Date: Wed, 02 Sep 2015 17:14:37 -0400
Organization: Self
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On 09/02/2015 04:18 PM, Stefan Ram wrote:
> Newsgroups: comp.lang.c,comp.lang.java.programmer
> 
> Richard Heathfield <rjh@cpax.org.uk> writes:
>> the programmer. In this case, it was this comment that led me to realise 
>> that the OP was interpreting his "spaces = height - number;" statement 
>> as defining some kind of self-updating relationship (like a spreadsheet 
>> formula).
> 
>   FWIW, in Java, one /can/ program in this way.
> 
> public final class Main
> { public static void main( final java.lang.String[] args )
>   {
> 
>     final javafx.beans.property.IntegerProperty height
>     = new javafx.beans.property.SimpleIntegerProperty( 10 );
> 
>     final javafx.beans.property.IntegerProperty number
>     = new javafx.beans.property.SimpleIntegerProperty(  2 );
> 
>     final javafx.beans.binding.NumberBinding spaces =
>     height.subtract( number );
> 
>     java.lang.System.out.println( spaces.getValue() );
> 
>     height.set( 20 );
> 
>     java.lang.System.out.println( spaces.getValue() ); }} /* prints:
> 
> 8
> 18                                                         */

What's the java feature that makes "spaces" above update automatically?
To put it another way - if I didn't want such updates, what should I
write differently?