方法参数传递: REPORT z_mehtod_para. *---------------------------------------------------------------------* * CLASS vehicle DEFINITION *---------------------------------------------------------------------* * ........ * *---------------------------------------------------------------------* CLASS vehicle DEFINITION. PUBLIC SECTION. METHODS: accelerate IMPORTING rate TYPE i, show_speed. PRIVATE SECTION. DATA speed TYPE i VALUE 0. ENDCLASS. *---------------------------------------------------------------------* * CLASS vehicle IMPLEMENTATION *---------------------------------------------------------------------* * ........ * *---------------------------------------------------------------------* CLASS vehicle IMPLEMENTATION. METHOD accelerate. speed = speed + rate. ENDMETHOD. METHOD show_speed. WRITE: / 'Speed:',speed. ENDMETHOD. ENDCLASS.
DATA o_vehicle TYPE REF TO vehicle.
START-OF-SELECTION. CREATE OBJECT o_vehicle. CALL METHOD o_vehicle->accelerate EXPORTING rate = 2. CALL METHOD o_vehicle->accelerate EXPORTING rate = 2. CALL METHOD o_vehicle->show_speed. 该示例输出如下: 4 方法还可以进行动态调用,即通过变量对方法进行指定,例如下列语句 meth = acclerate. call method o_vehicle->(meth).
函数方法: REPORT z_funtional_method.
*---------------------------------------------------------------------* * CLASS circle DEFINITION *---------------------------------------------------------------------* * ........ * *---------------------------------------------------------------------* CLASS circle DEFINITION. PUBLIC SECTION. METHODS get_area IMPORTING value(i_radius) TYPE i RETURNING value(r_size) TYPE f. PRIVATE SECTION. CONSTANTS pi TYPE f VALUE '3.14159265'. ENDCLASS. *---------------------------------------------------------------------* * CLASS circle IMPLEMENTATION *---------------------------------------------------------------------* * ........ * *---------------------------------------------------------------------* CLASS circle IMPLEMENTATION. METHOD get_area. r_size = i_radius ** 2 * pi. ENDMETHOD. ENDCLASS.
PARAMETERS radius TYPE i. DATA: o_circle TYPE REF TO circle, area TYPE f.
START-OF-SELECTION. CREATE OBJECT o_circle. CALL METHOD o_circle->get_area EXPORTING i_radius = radius RECEIVING r_size = area. WRITE: / area. area = o_circle->get_area( radius ). WRITE: / area.
构造方法和析构方法 1. 构造方法 构造方法是运行时环境自动调用的一种方法,用于为对象设定一个初始化状态,不能在程序运行过程中由程序代码调用.与其他方法类似构造方法也存在静态和实例两种形式.构造方法不一定需要在类中定
义,系统通常会自动生成一个默认的构造方法,将对象状态设置为初始值. 构造方法中不包含任何形式的输出参数,其功能只是定义对象状态,而不是对其进行改变.构造方法在create object语句中被调用,因此根据实例构造方法的定义,该语句本身也可以包含输出参数exporting和
返回值exception选项.如果在对象创建过程中出现异常,则对象被删除,引用变量设为初始值. 类构造方法属于静态方法,只能在程序中被调用一次,即第一次使用该类时调用,该方法也必须在公有部分声明,其名称必须为class_constructor. class-methods class_constructor. 类构造方法不包含接口,而且在其中只能访问类的静态属性. 构造方法: REPORT z_method_constructor. *---------------------------------------------------------------------* * CLASS vehicle DEFINITION *---------------------------------------------------------------------* * ........ * *---------------------------------------------------------------------* CLASS vehicle DEFINITION. PUBLIC SECTION. METHODS: accelerate IMPORTING rate TYPE i, constructor IMPORTING i_speed TYPE i, show_speed. PRIVATE SECTION. DATA speed TYPE i VALUE 0. ENDCLASS. *---------------------------------------------------------------------* * CLASS vehicle IMPLEMENTATION *---------------------------------------------------------------------* * ........ * *---------------------------------------------------------------------* CLASS vehicle IMPLEMENTATION. METHOD accelerate. speed = speed + rate. ENDMETHOD. METHOD show_speed. WRITE speed. ENDMETHOD. METHOD constructor. speed = i_speed. ENDMETHOD. ENDCLASS.
DATA o_vehicle TYPE REF TO vehicle.
START-OF-SELECTION. CREATE OBJECT o_vehicle EXPORTING i_speed = 4. CALL METHOD o_vehicle->accelerate EXPORTING rate = 2. CALL METHOD o_vehicle->accelerate EXPORTING rate = 2. CALL METHOD o_vehicle->show_speed. 该示例输出如下: 8 在对象创建过程中,通过构造方法传递了一个速度初始值作为其初始状态. 2. 析构方法 在某些面向对象语言中还存在析构方法的概念,该方法在对象删除过程中被调用,目前ABAP对象中尚未提供该方法的实现形式.
