ABAPCL_OBJECT_COLLECTION 工具类
原创 Tab Zhu [ SAP TAB ](javascript:void\(0\);)
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**_Title_ **
**ABAP-** **CL_OBJECT_COLLECTION**
本文参考Jerry Wang的程序学习了使用abap来实现java中ArrayList的功能，参考文章 [ SAP ABAP里存在Java
List这种集合工具类么？CL_OBJECT_COLLECTION了解一下
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**一**
**代码**
代码我是写在了本地，以便更容易看懂，主要用到了类接口和多态的思想，来避免重复造轮子。
REPORT ztest_polymorphism ."定义接口
INTERFACE zif_shape .
METHODS get_areaRETURNING
VALUE ( rv_result ) TYPE float .
ENDINTERFACE ."定义计算圆面积
CLASS zcl_circle DEFINITION .PUBLIC SECTION .
INTERFACES zif_shape .
METHODS constructorIMPORTING
!iv_radius TYPE float . "构造器，输入半径
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 ."定义计算矩形面积
CLASS zcl_rectangle DEFINITION .PUBLIC SECTION .
INTERFACES zif_shape .
METHODS constructorIMPORTING
!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 ."定义计算三角形面积
CLASS zcl_triangle DEFINITION .PUBLIC SECTION .
INTERFACES zif_shape .
METHODS constructorIMPORTING
!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 ,"定义一个内表来存放不同的实例
lv_result TYPE float .
START-OF-SELECTION .
"借助CL_OBJECT_COLLECTION, 采取面向对象编程里多态(Polymorphism)的思路
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 ( ) . "获取了一个迭代器WHILE lo_iterator -> has_next ( ) . "CL_OBJECT_COLLECTION_ITERATOR
DATA ( lo_shape ) = CAST zif_shape ( lo_iterator -> get_next ( ) ). "根据不同的类，返回值
lv_result = lv_result + lo_shape -> get_area ( ) .
ENDWHILE .WRITE : / lv_result . "圆，三角形，长方形的合计值
"这里可以实现将不同的实例加入到LT_SHAPE内表中，
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 . "圆，三角形，长方形的合计值
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