question: public static ObservableStringValue decision ( ObservableBooleanValue condition , ObservableStringValue ifTrue , ObservableStringValue ifFalse ) { StringProperty ret = new SimpleStringProperty ( ) ; condition . addListener ( null ) ; ifTrue . addListener ( null ) ; ifFalse . addListener ( null ) ; ret . set ( condition . get ( ) ? ifTrue . get ( ) : ifFalse . get ( ) ) ; return ret ; }
target:  Returns a new observable string which contains either the contents of ifTrue, or ifFalse, depending on the condition