定义装饰者抽象类，注意，他只不过继承了drink类，并没有作什么，我们需要的只不过是一个接口，一个装饰者和被装饰者的交互接口。
*Decorator definition, which will decorate the raw material
*The decorator should be as abstract class
*It is just for supply an interface, it won't implement
*any method of super class
*Or you could define new method here so that the subclass
*of decorator should have new method in it
class decorator definition abstract
inheriting from drink.
endclass.
class decorator implementation.
endclass.
*The decorator should be as abstract class
*It is just for supply an interface, it won't implement
*any method of super class
*Or you could define new method here so that the subclass
*of decorator should have new method in it
class decorator definition abstract
inheriting from drink.
endclass.
class decorator implementation.
endclass.
定义具体的装饰者
*Define the concrete decorator which will used to decorate
* the concrete drink object, for exp: darkroast
class mocha definition inheriting from decorator.
public section.
* Define the interface which will point to super class drink
data:
drink type ref to drink.
methods:
* Ininitialization
constructor
importing dr type ref to drink,
* Redifine the getdesc method so that we can get the right name
* of the decorated drink
getdesc redefinition,
* Redifine the cost method so that we can get the right price
* of the decorated drink
cost redefinition.
endclass.
class mocha implementation.
method constructor.
call method super->constructor.
* Make drink instance variant point to decorator
* For example, if darkroast decorated with mocha
* the reference drink shoul be pointed to darkroast
drink = dr.
endmethod.
method getdesc.
* This method will show how many decorate material we used
data: ls_mocha type string.
ls_mocha = drink->getdesc( ).
concatenate ls_mocha ',Mocha' into de.
endmethod.
method cost.
* Calculate the total price of the new drink which be decorated
* by the decorator
data: lf_mocha type f.
lf_mocha = drink->cost( ).
co = lf_mocha + '0.20'.
endmethod.
endclass.
* the concrete drink object, for exp: darkroast
class mocha definition inheriting from decorator.
public section.
* Define the interface which will point to super class drink
data:
drink type ref to drink.
methods:
* Ininitialization
constructor
importing dr type ref to drink,
* Redifine the getdesc method so that we can get the right name
* of the decorated drink
getdesc redefinition,
* Redifine the cost method so that we can get the right price
* of the decorated drink
cost redefinition.
endclass.
class mocha implementation.
method constructor.
call method super->constructor.
* Make drink instance variant point to decorator
* For example, if darkroast decorated with mocha
* the reference drink shoul be pointed to darkroast
drink = dr.
endmethod.
method getdesc.
* This method will show how many decorate material we used
data: ls_mocha type string.
ls_mocha = drink->getdesc( ).
concatenate ls_mocha ',Mocha' into de.
endmethod.
method cost.
* Calculate the total price of the new drink which be decorated
* by the decorator
data: lf_mocha type f.
lf_mocha = drink->cost( ).
co = lf_mocha + '0.20'.
endmethod.
endclass.
