来自于《大话设计模式》
状态模式（State）：当一个对象的内在状态改变时允许改变其行为，这个对象看起来像是改变了其类。
UML 类图：
代码实现 C++：
1 #include <iostream>
2 using namespace std;
3
4 class Work;
5 class State;
6 double getHour(Work* w);
7 void setState(Work * w, State * s);
8 bool getFinish(Work* w);
9 void WriteProgramOutside(Work * w);
10
11 class State
12 {
13 public:
14 virtual void WriteProgram(Work * w) = 0;
15 };
16
17 class RestState : public State
18 {
19 public:
20 virtual void WriteProgram(Work * w)
21 {
22 cout << "当前时间：" << getHour(w) << " 点下班回家了。" << endl;
23 }
24 };
25
26 class SleepingState : public State
27 {
28 public:
29 virtual void WriteProgram(Work * w)
30 {
31 cout << "当前时间：" << getHour(w) << " 点不行了，睡着了。" << endl;
32 }
33 };
34
35 class EveningState : public State
36 {
37 public:
38 virtual void WriteProgram(Work * w)
39 {
40 if (getFinish(w))
41 {
42 setState(w, static_cast<State*>(new RestState));
43 WriteProgramOutside(w);
44 }
45 else
46 {
47 if (getHour(w) < 21.0)
48 {
49 cout << "当前时间：" << getHour(w) << " 点 加班哦，疲惫之极。" << endl;
50 }
51 else
52 {
53 setState(w, new SleepingState);
54 WriteProgramOutside(w);
55 }
56 }
57 }
58 };
59
60 class AfternoonState : public State
61 {
62 public:
63 virtual void WriteProgram(Work * w)
64 {
65 if (getHour(w) < 17.0)
66 {
67 cout << "当前时间：" << getHour(w) << " 点 下午状态还不错，继续努力。" << endl;
68 }
69 else
70 {
71 setState(w, new EveningState);
72 WriteProgramOutside(w);
73 }
74 }
75 };
76
77 class NoonState : public State
78 {
79 public:
80 virtual void WriteProgram(Work * w)
81 {
82 if (getHour(w) < 13.0)
83 {
84 cout << "当前时间：" << getHour(w) << " 点 饿了，午饭；犯困，午休。" << endl;
85 }
86 else
87 {
88 setState(w, new AfternoonState);
89 WriteProgramOutside(w);
90 }
91 }
92 };
93
94 class ForenoonState : public State
95 {
96 public:
97 virtual void WriteProgram(Work* w)
98 {
99 if (getHour(w) < 12.0)
100 {
101 cout << "当前时间：" << getHour(w) << " 点 上午工作，精神百倍！" << endl;
102 }
103 else
104 {
105 setState(w, new NoonState);
106 WriteProgramOutside(w);
107 }
108 }
109 };
110
111 class Work
112 {
113 private:
114 State * current;
115 double hour;
116 bool finish;
117 public:
118 double getHour()
119 {
120 return hour;
121 }
122 void setHour(double h)
123 {
124 hour = h;
125 }
126 bool getFinish()
127 {
128 return finish;
129 }
130 void setFinsh(bool f)
131 {
132 finish = f;
133 }
134 void setState(State * w)
135 {
136 delete current;
137 current = w;
138 }
139 void WriteProgram()
140 {
141 current->WriteProgram(this);
142 }
143 Work()
144 {
145 current = new ForenoonState;
146 finish = false;
147 }
148 ~Work()
149 {
150 delete current;
151 }
152 };
153
154 double getHour(Work * w)
155 {
156 return w->getHour();
157 }
158 void setHour(Work * w, double h)
159 {
160 w->setHour(h);
161 }
162 bool getFinish(Work * w)
163 {
164 return w->getFinish();
165 }
166 void setFinish(Work * w, bool f)
167 {
168 w->setFinsh(f);
169 }
170 void setState(Work * w, State * s)
171 {
172 w->setState(s);
173 }
174
175 void WriteProgramOutside(Work * w)
176 {
177 w->WriteProgram();
178 }
179
180 int main()
181 {
182 Work* emergencyProjects = new Work;
183 emergencyProjects->setHour(9.0);
184 emergencyProjects->WriteProgram();
185 emergencyProjects->setHour(10.0);
186 emergencyProjects->WriteProgram();
187 emergencyProjects->setHour(12.0);
188 emergencyProjects->WriteProgram();
189 emergencyProjects->setHour(13.0);
190 emergencyProjects->WriteProgram();
191 emergencyProjects->setHour(14.0);
192 emergencyProjects->WriteProgram();
193 emergencyProjects->setHour(17.0);
194 emergencyProjects->WriteProgram();
195
196 // emergencyProjects->setFinsh(true);
197 emergencyProjects->setFinsh(false);
198
199 emergencyProjects->WriteProgram();
200 emergencyProjects->setHour(19.0);
201 emergencyProjects->WriteProgram();
202 emergencyProjects->setHour(22.0);
203 emergencyProjects->WriteProgram();
204
205 delete emergencyProjects;
206 return 0;
207 }
posted on 2011-04-27 16:39
unixfy 阅读(204)
评论(0) 编辑 收藏 引用