blob: 861362151877f47dce6de68e23be8864afdd5a26 (
plain)
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
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
|
/* Listing1018.java */
interface MenuVisitor
{
abstract void visitMenuEntry(MenuEntry2 entry);
abstract void visitMenuStarted(Menu2 menu);
abstract void visitMenuEnded(Menu2 menu);
}
class MenuEntry2
{
protected String name;
public MenuEntry2(String name)
{
this.name = name;
}
public String toString()
{
return name;
}
public void accept(MenuVisitor visitor)
{
visitor.visitMenuEntry(this);
}
}
class Menu2
extends MenuEntry2
{
MenuEntry2[] entries;
int entryCnt;
public Menu2(String name, int maxElements)
{
super(name);
this.entries = new MenuEntry2[maxElements];
entryCnt = 0;
}
public void add(MenuEntry2 entry)
{
entries[entryCnt++] = entry;
}
public String toString()
{
String ret = "(";
for (int i = 0; i < entryCnt; ++i) {
ret += (i != 0 ? "," : "") + entries[i].toString();
}
return ret + ")";
}
public void accept(MenuVisitor visitor)
{
visitor.visitMenuStarted(this);
for (int i = 0; i < entryCnt; ++i) {
entries[i].accept(visitor);
}
visitor.visitMenuEnded(this);
}
}
class MenuPrintVisitor
implements MenuVisitor
{
String indent = "";
public void visitMenuEntry(MenuEntry2 entry)
{
System.out.println(indent + entry.name);
}
public void visitMenuStarted(Menu2 menu)
{
System.out.println(indent + menu.name);
indent += " ";
}
public void visitMenuEnded(Menu2 menu)
{
indent = indent.substring(1);
}
}
public class Listing1018
{
public static void main(String[] args)
{
Menu2 filemenu = new Menu2("Datei", 5);
filemenu.add(new MenuEntry2("Neu"));
filemenu.add(new MenuEntry2("Laden"));
filemenu.add(new MenuEntry2("Speichern"));
Menu2 confmenu = new Menu2("Konfiguration", 3);
confmenu.add(new MenuEntry2("Farben"));
confmenu.add(new MenuEntry2("Fenster"));
confmenu.add(new MenuEntry2("Pfade"));
filemenu.add(confmenu);
filemenu.add(new MenuEntry2("Beenden"));
filemenu.accept(new MenuPrintVisitor());
}
}
|
