Design Patterns Java™ Workbook

Appendix B. Solutions

Strategy (Chapter 23)................................................................................................................................

SOLUTION 23.1....................................................................................................................................

The GroupAdvisor and ItemAdvisor classes are instances of ADAPTER, providing
the interface a client expects, using the services of a class with a different interface.

SOLUTION 23.2....................................................................................................................................

Figure B.26 shows one solution.

Figure B.26. The advertising policy at Oozinoz includes four strategies that appear as four

implementations of the Advisor interface.

SOLUTION 23.3....................................................................................................................................

The code for ItemAdvisor.java should look something like:

package com.oozinoz.recommend;
import com.oozinoz.fireworks.*;
public class ItemAdvisor implements Advisor
{
public static final ItemAdvisor singleton =
new ItemAdvisor();
private ItemAdvisor() {}