ABAP中的指针（如Java中的指针）

Question

Could anyone tell me how to define a pointer in ABAP OO? In Java I have no problems with it, eg. this.name or this.SomeMethod() .

Answer 1

Probably you are asking about so called self reference.

In ABAP it is available by using keyword me .

Example in Java: this.someMethod();
Example in ABAP: me->someMethod( ).

Answer 2

ABAP uses field symbols. They are defined like: FIELD-SYMBOLS: , " TYPE any. TYPE file_table. If you want to dereference it, you need to do it using another field symbol like this:

ASSIGN str_mfrnr TO <str1>. 

This Stores the value of str_mfrnr into the field symbol. If this is formatted as a work area like 'wa_itab-my_column', will now contain this string. Next, assign the location to another FS:

ASSIGN (<str1>) TO <tmfrnr>.

now points to wa_itab-my_column. If you perform:

<tmfrnr> = some_value.

the location pointed to by now contains the value in some_value. ABAP pointers are more like C pointers, you have to know whether you are referenceing the value or the location.

Answer 3

Here's a small report I wrote a while ago to wrap my head around it. I think this is how it works:

REPORT  zpointers.

* Similar to C:
***************
*  int *pointer;
*  int value = 1.
*  pointer = &value
*  int deref = *pointer

*this is the variable
DATA int TYPE i VALUE 10.
*this is the pointer, or the reference to a memory address
DATA pointer_i TYPE REF TO i.
*this is the dereferenced value, or the var that points to the
*value stored in a particular memory address
FIELD-SYMBOLS <int> TYPE i.

*the memory address of variable 'int' is now assigned to
*variable 'pointer_i'.
GET REFERENCE OF int INTO pointer_i.

*you can access the pointer by dereferencing it to a field symbol.
ASSIGN pointer_i->* TO <int>.