Solutions - Design Patterns Java - page 354

Iterator (Chapter 28)
SOLUTION 28.1
A working program is:
package com.oozinoz.applications;
import com.oozinoz.fireworks.*;
public class ShowFireworkList
{
public static void main(String[] args)
{
FireworkList flist =
Promo.getPromotionalFireworks();
FireworkList.Itr i = flist.iterator();
while (i.hasNext())
{
Firework f = i.next();
System.out.println(
f.getName()
+ ", $" + f.getPrice()
+ ", " + f.getType());
}
}
}
SOLUTION 28.2
As Chapter 16, Factory Method, describes, iterators provide a classic example of
the F ACTORY M ETHOD pattern. A client that wants an iterator for an instance of
a ProcessComponent knows when to create the iterator, but the receiving class knows
which class to instantiate.
SOLUTION 28.3
You need to change the next() code to not return the node of a composite that you're
iterating over. You also need to pass along the value of the showInterior Boolean to
subiterators you create:
public Object next()
{
if (peek != null)
{
Object o = peek;
peek = null;
return o;
}
if (!visited.contains(node))
{
visited.add(node);