ABAP-CL_ OBJECT_ Collection tool class

Title

ABAP-CL_OBJECT_COLLECTION

In this paper, the reference Jerry Wang The program learned to use abap To achieve java in ArrayList The function of , Reference article SAP ABAP In existence Java List This kind of tool class ？CL_OBJECT_COLLECTION Get to know

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Code

I wrote the code locally , To make it easier to understand , It mainly uses the idea of class interface and polymorphism , To avoid repeating the wheel .

REPORT ztest_polymorphism.

" Defining interfaces

INTERFACE zif_shape. METHODS get_area RETURNING VALUE(rv_result) TYPE float. ENDINTERFACE. " Define calculation circle area CLASS zcl_circle DEFINITION. PUBLIC SECTION. INTERFACES zif_shape. METHODS constructor IMPORTING !iv_radius TYPE float ." Constructors , Enter the radius PROTECTED SECTION. PRIVATE SECTION. DATA radius TYPE float . ENDCLASS. CLASS zcl_circle IMPLEMENTATION. METHOD constructor. me->radius = iv_radius. ENDMETHOD. METHOD zif_shape~get_area. CONSTANTS: pai TYPE float VALUE '3.14'. rv_result = pai * radius * radius. ENDMETHOD. ENDCLASS. " Define calculation rectangle area CLASS zcl_rectangle DEFINITION. PUBLIC SECTION. INTERFACES zif_shape. METHODS constructor IMPORTING !iv_height TYPE float !iv_width TYPE float . PROTECTED SECTION. PRIVATE SECTION. DATA height TYPE float . DATA width TYPE float . ENDCLASS. CLASS zcl_rectangle IMPLEMENTATION. METHOD constructor. height = iv_height. width = iv_width. ENDMETHOD. METHOD zif_shape~get_area. rv_result = width * height. ENDMETHOD. ENDCLASS. " Define calculation triangle area CLASS zcl_triangle DEFINITION. PUBLIC SECTION. INTERFACES zif_shape. METHODS constructor IMPORTING !iv_side TYPE float !iv_height TYPE float . PROTECTED SECTION. PRIVATE SECTION. DATA side TYPE float . DATA height TYPE float . ENDCLASS. CLASS zcl_triangle IMPLEMENTATION. METHOD constructor. side = iv_side. height = iv_height. ENDMETHOD. METHOD zif_shape~get_area. rv_result = ( 1 / 2 ) * side * height. ENDMETHOD. ENDCLASS.

TYPES: BEGIN OF ty_shape, shape TYPE REF TO object, END OF ty_shape. TYPES: tt_shape TYPE STANDARD TABLE OF ty_shape. DATA: lt_shape TYPE tt_shape," Define an inner table to store different instances lv_result TYPE float.

START-OF-SELECTION. " With the help of CL_OBJECT_COLLECTION, Adopt polymorphism in object-oriented programming (Polymorphism) The idea of DATA(lo_container) = NEW cl_object_collection( ). DATA(lo_circle) = NEW zcl_circle( 1 ). lo_container->add( lo_circle )." DATA(lo_rectangle) = NEW zcl_rectangle( iv_width = 1 iv_height = 2 ). lo_container->add( lo_rectangle ). DATA(lo_triangle) = NEW zcl_triangle( iv_height = 2 iv_side = 3 ). lo_container->add( lo_triangle ). DATA(lo_iterator) = lo_container->get_iterator( )." Got an iterator WHILE lo_iterator->has_next( )."CL_OBJECT_COLLECTION_ITERATOR DATA(lo_shape) = CAST zif_shape( lo_iterator->get_next( ) )." According to different classes , Return value lv_result = lv_result + lo_shape->get_area( ). ENDWHILE. WRITE:/ lv_result." round , triangle , Total value of rectangle " Here you can add different instances to LT_SHAPE In the inner table ,

DATA(entry) = VALUE ty_shape( shape = lo_circle ). APPEND entry TO lt_shape. entry = VALUE ty_shape( shape = lo_rectangle ). APPEND entry TO lt_shape. entry = VALUE ty_shape( shape = lo_iterator ). APPEND entry TO lt_shape. CLEAR lv_result.

LOOP AT lt_shape REFERENCE INTO DATA(lr_shape). lo_shape = CAST zif_shape( lr_shape->shape ). lv_result = lv_result + lo_shape->get_area( ). ENDLOOP. WRITE:/ lv_result." round , triangle , Total value of rectangle