【IT168 技术文章】
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.
