SAP ABAP/4学习--学习使用OO在ABAP中.简单入门概念.用个例子来说明

REPORT ZHEF_ABAP_OBJECTS_EXAMPLE2.
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* Local classes Example 2
* Using enheritance
* Raising and handling events
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* Super class Empolyee
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*定义一个父类,只是定义里面的一些数据类型,
* 具体的方法和内容在下面实现.
CLASS Employee DEFINITION.
*定义公共部分的数据和方法
PUBLIC SECTION.
 DATA:
      nEmployeeNo(4)       type n,   “雇员员工号
      cEmployeeName(30)    type c,   “雇员姓名
      iNoOfUnits           type i,   “生产的的单元的数量
      iPayPerUnit          type i.   “每个单元的价格
 
*定义两个方法,一个是输出,一个是输入
 METHODS:
      CalculatePay RETURNING VALUE(iPay) TYPE i,
      WritePay     IMPORTING VALUE(iPay) TYPE i.
ENDCLASS.
 
 
*这里是具体的实现的
CLASS Employee IMPLEMENTATION.
*实现上面的方法
 METHOD CalculatePay.
 
    iPay = iNoOfUnits * iPayPerUnit.
 ENDMETHOD.
 
 METHOD WritePay.
 
    WRITE: / 'The pay for employee ',
             nEmployeeNo, cEmployeeName,
             ' is : ', iPay.
 ENDMETHOD.
 
ENDCLASS.
 
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* Subclass Factory Worker
*
* The class FactoryWorker is a subclass of the superclass Employee.
* Note that the attribute iExtraNoUnits have been added and the
* method CalculatePay has been redefined.
 
*
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*定义一个子类.从父类中继承过来
CLASS FactoryWorker DEFINITION INHERITING FROM Employee.
 PUBLIC SECTION.
*   定义个事件.  
EVENTS: LazyEmployee.  
 
* 增加一个属性
    DATA: iExtraNoUnits type i.
 
*覆盖父的方法,现在从新定义CalculatePay.
    METHODS:
*     Redefinition af the CalculatePay method from the Superclass
      CalculatePay REDEFINITION.
 
ENDCLASS.
 
*现在实现这个个子类.
CLASS FactoryWorker IMPLEMENTATION.
 METHOD CalculatePay.
* 从新定义方法
 
    iPay = ( iNoOfUnits * iPayPerUnit ) +
           ( iExtraNoUnits * iPayPerUnit * 2 ).
          
*   抛出处理
    IF iNoOfUnits < 100.
      raise event LazyEmployee.     
    ENDIF.
 ENDMETHOD.
 
ENDCLASS.
 
************************************************************************
* This class only to show how you can handle an event that have been
* raised in another class
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* 这个类只能处理一个在其他类中抛出的事件.
* 被开除的员工的类的定义
CLASS FireEmployee DEFINITION.
 
 PUBLIC SECTION.
*   Method for handling the event LazyEmployee in the FactoryWorker
*   subclass.
*   定义YOUAREFIRED方法为FACTORYWORKER类中的LAZYEMPLOYEE事件.  
    METHODS YouAreFired
            FOR EVENT LazyEmployee
            OF FactoryWorker.
ENDCLASS.
 
 
 
 
 
 
 
 
*来实现这个CLASS吧
* 然后实现具体的方法,就是输出一句话,具体处理.
CLASS FireEmployee IMPLEMENTATION.
 METHOD YouAreFired.   
    WRITE:/ 'You lazy worker, you have produced less than 100 units.'
           color col_heading,
           'YOU ARE FIRED !!!' color col_negative intensified.
 
 ENDMETHOD.
ENDCLASS.
 
 
*下面是使用CLASS
************************************************************************
* U S I N G   T H E   C L A S S E S
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DATA: MyPay TYPE i.
 
START-OF-SELECTION.
*-----------------------------------------------------------------------
* Using the superclass Employee
*-----------------------------------------------------------------------
 
* Declare new Employee from the EmployeeClass
 
 DATA: SamSmith TYPE REF TO Employee.
 
 CREATE OBJECT: SamSmith.
 SamSmith->nEmployeeNo = 433.
 SamSmith->cEmployeeName = 'Sam Smith'.
 SamSmith->iNoOfUnits = 150.
 SamSmith->iPayPerUnit = 3.
 MyPay = SamSmith->CalculatePay( ).
 CALL METHOD SamSmith->WritePay( MyPay ).
 SKIP.
 
*-----------------------------------------------------------------------
* Using the subclass FactoryWorker
*-----------------------------------------------------------------------
 
* Declare new FactoryWorker as subclass of the EmployeeClass
 DATA: JessicaJones TYPE REF TO FactoryWorker.
 
 CREATE OBJECT: JessicaJones.
 
 JessicaJones->nEmployeeNo = 1500.
 JessicaJones->cEmployeeName = 'Jessica Jones'.
 JessicaJones->iNoOfUnits = 300.
 JessicaJones->iExtraNoUnits = 500.      “子类中额外的一些单元
 JessicaJones->iPayPerUnit = 3.
 MyPay = JessicaJones->CalculatePay( ).
 CALL METHOD JessicaJones->WritePay( MyPay ).
 SKIP.
 
 
 
* 以下是处理一个事件所写的例子,上面的两个,一个用到父类,一个用到了子类.
* 现在是用到事件处理的例子.
 
 
*-----------------------------------------------------------------------
 
* Using the subclass FactoryWorker with event
*-----------------------------------------------------------------------
*定义个员工实例
*再定义个处理事件的对象
 
 DATA: LazyJohn TYPE REF TO FactoryWorker,
        FireHim TYPE REF TO FireEmployee.
 
 CREATE OBJECT: LazyJohn,
                  FireHim.
 
 
 
* The SET HANDLER statement, registers a runtime trigger.
* It links a list of handler methods to corresponding event triggers
* Each SET HANDLER statement creates an entry in an event handler table
 
* 为LAZYJOHN设置一个处理HANDLER ,具体的方法是
 SET HANDLER FireHim->YouAreFired FOR LazyJohn.
 
 LazyJohn->nEmployeeNo = 1500.
 LazyJohn->cEmployeeName = 'Lazy John'.
 LazyJohn->iNoOfUnits = 90.
 LazyJohn->iExtraNoUnits = 500.
 LazyJohn->iPayPerUnit = 3.
 WRITE: / 'Lazy John has produced less than 100 units'.
 MyPay = LazyJohn->CalculatePay( ).