Design Patterns Java™ Workbook

Chapter 28. Iterator

Figure 28.1. The FireworkList class provides type-specific lists for Firework objects.

The Itr class is an inner class for FireworkList.

The FireworkList class stores its objects in a regular instance of ArrayList. The add()
method ensures that only Firework objects enter the list. For example, the Promo class
creates and returns a list of promotional fireworks, using a FireworkList object:

package com.oozinoz.fireworks;
import com.oozinoz.units.*;
public class Promo implements UnitConstants
{

public static FireworkList getPromotionalFireworks()
{
FireworkList fl = new FireworkList();
fl.add(new Sparkler("Brightful", .35));
fl.add(new Firecracker("Frightful", .19));
fl.add
(
new Rocket(
"Heightful",
33.95,
(Length) METER.times(300))
);