class Client public void Main Aggregate new ConcreteAggregate Iterator

 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
class Client
{
public void Main()
{
Aggregate a = new ConcreteAggregate();
Iterator i = a.CreateIterator();
object item = i.First();
while (!i.IsDone())
{
item = i.Next();
}
}
}
abstract class Aggregate
{
public abstract Iterator CreateIterator();
public abstract int Count { get; protected set; }
public abstract object this[int index] { get; set; }
}
class ConcreteAggregate : Aggregate
{
private readonly ArrayList _items = new ArrayList();
public override Iterator CreateIterator()
{
return new ConcreteIterator(this);
}
public override int Count
{
get { return _items.Count; }
protected set { }
}
public override object this[int index]
{
get { return _items[index]; }
set { _items.Insert(index, value); }
}
}
abstract class Iterator
{
public abstract object First();
public abstract object Next();
public abstract bool IsDone();
public abstract object CurrentItem();
}
class ConcreteIterator : Iterator
{
private readonly Aggregate _aggregate;
private int _current;
public ConcreteIterator(Aggregate aggregate)
{
this._aggregate = aggregate;
}
public override object First()
{
return _aggregate[0];
}
public override object Next()
{
object ret = null;
_current++;
if (_current < _aggregate.Count)
{
ret = _aggregate[_current];
}
return ret;
}
public override object CurrentItem()
{
return _aggregate[_current];
}
public override bool IsDone()
{
return _current >= _aggregate.Count;
}
}