Design Patterns Java™ Workbook

Visitor (Chapter 29)

SOLUTION 29.1

The difference is in the type of the this object. The accept() method calls the visit() method of a MachineVisitor object. The accept() method in the Machine class will look up a visit() method with the signature visit(Machine), whereas the accept() method in the MachineComposite class will look up a method with the signature visit(MachineComposite).

SOLUTION 29.2

One solution is: package com.oozinoz.applications; import com.oozinoz.machine.*; import com.oozinoz.dublin.*; public class ShowFind { public static void main(String[] args) { MachineComponent f = OozinozFactory.dublin(); System.out.println(new FindVisitor().find(f, 3404)); } } This program successfully prints out: StarPress3404

SOLUTION 29.3

A solution ...