状态模式就是将状态的条件判断语句转化成其函数重写形式，利用了面向对象语言的多态性，本文根据https://blog.csdn.net/lm324114/article/details/78819602的情景将状态模式用matlab语言实现。
根据上图情景，用传统的方法实现如下：
roomstate.m
我要评论classdef roomstate < handle
enumeration
free
booked
checkin
end
end
ifroom.m
classdef ifroom < handle
properties
state;
end
methods
function obj = ifroom()
obj.state = roomstate.free;
end
function bookroom(obj)
switch obj.state
case roomstate.free
disp('完成预订...');
obj.state = roomstate.booked;
case roomstate.booked
disp('该房间已经被预订了...');
case roomstate.checkin
disp('该房间已经有人入住了...');
end
end
function checkinroom(obj)
switch obj.state
case roomstate.free
disp('空闲房间，入住..');
obj.state = roomstate.checkin;
case roomstate.booked
disp('入住房间....');
obj.state = roomstate.checkin;
case roomstate.checkin
disp('该房间已经有人入住了...');
end
end
function unsubscriberoom(obj)
switch obj.state
case roomstate.free
disp('该房间尚未预订');
case roomstate.booked
disp('已退订房间...');
obj.state = roomstate.free;
case roomstate.checkin
disp('该房间已入住，不能退订');
end
end
function checkoutroom(obj)
switch obj.state
case {roomstate.free, roomstate.booked}
disp('该房间尚未入住');
case roomstate.checkin
disp('已退房');
obj.state = roomstate.free;
end
end
end
end
测试代码：
ri = ifroom();
ri.bookroom();
ri.checkoutroom();
ri.unsubscriberoom();
ri.checkinroom();
ri.checkoutroom();
用状态模式实现如下：
state.m
classdef state < handle
properties
state;
end
methods(abstract)
bookroom(obj);
checkinroom(obj)
unsubscriberoom(obj)
checkoutroom(obj)
end
end
freestate.m
classdef freestate < state
properties
room
end
methods
function obj = freestate(room)
obj.room = room;
end
function bookroom(obj)
disp('完成预订...');
obj.room.state = obj.room.booked_state;
end
function checkinroom(obj)
disp('空闲房间，入住..');
obj.room.state = obj.room.checkin_state;
end
function unsubscriberoom(~)
disp('该房间尚未预订');
end
function checkoutroom(~)
disp('该房间尚未入住');
end
end
end
bookedstate.m
classdef bookedstate < state
properties
room
end
methods
function obj = bookedstate(room)
obj.room = room;
end
function bookroom(~)
disp('该房间已经被预订了...');
end
function checkinroom(obj)
disp('入住房间....');
obj.room.state = obj.room.checkin_state;
end
function unsubscriberoom(obj)
disp('已退订房间...');
obj.room.state = obj.room.free_state;
end
function checkoutroom(~)
disp('该房间尚未入住');
end
end
end
checkinstate.m
classdef checkinstate < state
properties
room
end
methods
function obj = checkinstate(room)
obj.room = room;
end
function bookroom(~)
disp('该房间已经有人入住了...');
end
function checkinroom(~)
disp('该房间已经有人入住了...');
end
function unsubscriberoom(~)
disp('该房间已入住，不能退订');
end
function checkoutroom(obj)
disp('已退房');
obj.room.state = obj.room.free_state;
end
end
end
room.m
classdef room < handle
properties
free_state;
booked_state;
checkin_state;
end
properties
state;
end
methods
function obj = room()
obj.free_state = freestate(obj);
obj.booked_state = bookedstate(obj);
obj.checkin_state = checkinstate(obj);
obj.state = obj.free_state;
end
function bookroom(obj)
obj.state.bookroom();
end
function checkinroom(obj)
obj.state.checkinroom();
end
function unsubscriberoom(obj)
obj.state.unsubscriberoom();
end
function checkoutroom(obj)
obj.state.checkoutroom();
end
end
end
测试代码
r = room();
r.bookroom();
r.checkoutroom();
r.unsubscriberoom();
r.checkinroom();
r.checkoutroom();
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