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  • ABAPOBJECTS ABAP的类的基础知识

    一、Class Define
    1) Basis Structure of Class
    CLASS c1 DEFINITION.
      PUBLIC SECTION.
        DATA: a1 …
        METHODS: m1 …
        EVENTS: e1 …
      PROTECTED SECTION.
        DATA: a2 …
        METHODS: m2 …
        EVENTS: e2 …
      PRIVATE SECTION.
        DATA: a3 …
        METHODS: m3 …
        EVENTS: e3 …
    ENDCLASS.

    CLASS c1 IMPLEMENTATION.
      METHOD m1. …
      ENDMETHOD.
      METHOD m2. …
      ENDMETHOD.
      METHOD m3. …
      ENDMETHOD.
    ENCLASS.

    2) Components of Classes: Attributes' Type
    CLASS ... DEFINITION
      ....
      ...SECTION.
        DATA... TYPE ... [READ-ONLY] ...
        CLASS-DATA... TYPE ... [READ-ONLY] ...
        CONSTANTS... TYPE ... VALUE ...
        ...
    ENDCLASS.
    DATA:                   Instance attributes
    CLASS-DATA:    Staticattributes
    CONSTANTS:    Constants


    3)Components of Classes:Methods' type
    CLASS ... DEFINITION
      ....
      ...SECTION.
        METHODS... IMPORTING [VALUE] ... TYPE ... [OPTIONAL]
          EXPORTING [VALUE] ... TYPE ...
          CHANGING [VALUE] ... TYPE ... [OPTIONAL]
          RETURNING VALUE(...) TYPE ...
          EXCEPTIONS ...
        CLASS-METHODS...
        ...
    ENDCLASS.
    METHODS:                Instance methods
    CLASS-METHODS: Staticmethods

    4)Constructors' type
    CLASS ... DEFINITION
      ....
        PUBLIC SECTION.
          METHODS CONSTRUCTOR
            [IMPORTING arg1 TYPEtype... ].
          CLASS-METHODS CLASS_CONSTRUCTOR.
        ...
    ENDCLASS.

    二、Using Object Step
    1)Declaring referencevariables

    DATA: ref1 TYPE REF TO class,
                ref2 TYPE REFTO  class.

    2)Creating objects
    DATA: CREATE OBJECT: ref1,

    3)Accessing attributes and methods
    ref2.x = ref1->attr+ ref2->attr.
    CALL METHOD ref1->methodEXPORTING ...

    三、Accessing the components of classes
    1)Instance components:           ref–>comp
    Instance attribute:                   ref->attr
    Instance method:                   call method ref->meth

    2)Static components                 class=>comp
    Static attribute:                        class=>attr
    Static method:                         call method class=>meth

    3)Special references in methods
    Self reference:               ME->comp
    Pseudo reference         SUPER->comp 

    四、Class Inhireritance(abap只支持单继承)
    1)Inheritance-Overview
    CLASS c1 DEFINITION INHERITING FROM ...
       ...
    ENDCLASS.

    2)Redefining Methods
    CLASS ... DEFINITION INHERITING FROM ...
       ... SECTION.
           METHODS ... REDEFINITON ...
       ......
    ENDCLASS.

    五) Interface(待续)

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  • 原文地址:https://www.cnblogs.com/xiaomaohai/p/6157161.html
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