今日学习ABAP面向对象里面的类，关于构造，继承，实现。

踩坑点：类有抽象的方法，类本身也需要是抽象的，故需要在类申明里面加上ABSTRACT关键字

学习资料为B站翱翔云天老师的

 1 CLASS zcl_employee DEFINITION
 2   PUBLIC
 3   ABSTRACT
 4   CREATE PUBLIC .
 5 
 6   PUBLIC SECTION.
 7     METHODS:
 8         constructor IMPORTING firstname TYPE string
 9                               lastname TYPE string,
10         get_printname RETURNING VALUE(fullname) TYPE string,
11         earnings  ABSTRACT RETURNING VALUE(earn) TYPE f,
12         print ABSTRACT.
13   PROTECTED SECTION.
14      data:first_name TYPE string,
15           last_name TYPE string.
16 
17   PRIVATE SECTION.
18 ENDCLASS.

练习类的结构

父类：Employee 子类：Boss，PieceWorker，SalesPerson

Employee类

boss类

CLASS zcl_boss IMPLEMENTATION.
    METHOD constructor.
        CALL method super->constructor
            EXPORTING
                firstname = fn
                lastname = ln.
                weekly_salary = wl.
    ENDMETHOD.

     METHOD set_weekly_salary.
        weekly_salary = ws.
    ENDMETHOD.

    METHOD earnings.
        earn = weekly_salary * 4.
    ENDMETHOD.



    METHOD print.
        write:/,'My name is:',  get_printname( ).
        write:/,'My salary is:',  me->earnings( )  DECIMALS 2 EXPONENT 0.
    ENDMETHOD.


ENDCLASS.

CLASS zcl_piece_worker DEFINITION
  PUBLIC
  INHERITING FROM zcl_employee
  FINAL
  CREATE PUBLIC .

  PUBLIC SECTION.
    METHODS:
      constructor IMPORTING fn       TYPE string
                            ln       TYPE string
                            wage     TYPE f
                            quantity TYPE i,

      setwage IMPORTING wage TYPE f,
      setquantity IMPORTING quantity TYPE i,
      earnings REDEFINITION,
      print REDEFINITION.
  PROTECTED SECTION.
  PRIVATE SECTION.
    DATA: wagevalue     TYPE f,
          quantityValue TYPE i.

ENDCLASS.


PieceWorker类
CLASS zcl_piece_worker IMPLEMENTATION.
  METHOD constructor.
    CALL METHOD super->constructor
      EXPORTING
        firstname = fn
        lastname  = ln.
    wagevalue = wage.
    quantityValue = quantity.
  ENDMETHOD.

  METHOD setwage.
    wagevalue = wage.
  ENDMETHOD.

  METHOD setquantity.
    quantityValue = quantity.
  ENDMETHOD.

  METHOD earnings.
    earn = wagevalue * quantityValue.
  ENDMETHOD.

  METHOD print.
    WRITE:/,'my name is:', get_printname( ).
    WRITE:/,'我的收入是：',me->earnings( )  DECIMALS 2 EXPONENT 0.

  ENDMETHOD.




ENDCLASS.

CLASS zcl_sales DEFINITION
  PUBLIC
  INHERITING FROM zcl_employee
  FINAL
  CREATE PUBLIC .

  PUBLIC SECTION.
    METHODS:
      constructor IMPORTING
                    fn   TYPE string
                    ln   TYPE string
                    sal  TYPE f
                    comm TYPE float
                    quan TYPE i,
      setSalary  IMPORTING sal TYPE f,
      setComm IMPORTING comm TYPE f,
      setQuantity IMPORTING qu    TYPE i,
      earnings   REDEFINITION,
      print  REDEFINITION.


  PROTECTED SECTION.
  PRIVATE SECTION.
    DATA:salary     TYPE f,
         commission TYPE f,
         quantity   TYPE i.
ENDCLASS.



SalesMan类
CLASS zcl_sales IMPLEMENTATION.
  METHOD constructor.
    CALL METHOD super->constructor
      EXPORTING
        firstname = fn
        lastname  = ln.
    salary = sal.
    commission = comm.
    quantity = quan.
  ENDMETHOD.


  METHOD  setSalary.
    salary = sal.
  ENDMETHOD.


  METHOD  setComm.
    commission = comm.
  ENDMETHOD.


  METHOD  setQuantity.
    quantity = qu.
  ENDMETHOD.


  METHOD  earnings.
    earn = salary + commission * quantity.
  ENDMETHOD.


  METHOD print.
    WRITE:/,'my name is:', get_printname( ).
    WRITE:/,'我的收入是：',me->earnings( )  DECIMALS 2 EXPONENT 0.

  ENDMETHOD.

ENDCLASS.

*&---------------------------------------------------------------------*
*& Report zaxyt_employee_demo
*&---------------------------------------------------------------------*
*& 员工类的测试程序
*&---------------------------------------------------------------------*
REPORT zaxyt_employee_demo.



主程序
DATA: o_sales TYPE REF TO zcl_sales,
      o_boss  TYPE REF TO zcl_boss,
      o_emp   TYPE REF TO zcl_employee.

CREATE OBJECT o_sales
  EXPORTING
    fn   = 'David'
    ln   = 'Go'
    sal  = '1222.88'
    comm = '0.5'
    quan = 15000.

o_emp = o_sales.
o_sales->print( ).

CREATE OBJECT o_boss
  EXPORTING
    fn = '王麻子'
    ln = '尼古拉斯'
    wl = '1000'.

o_emp = o_boss.
o_boss->print( ).