Table type with reference type - how to sort?

Question

I have an internal table lt_refs of the type ZXX_TT_REFS.
The table type ZXX_TT_REFS is a table of references ("ref. type") to the class ZCL_C.
The class C has an attribute attr1.
Now I would like to sort that table. Is there an easy (built-in) way to do this?
DATA lt_refs TYPE ZXX_TT_REFS.
DATA lr_ref  TYPE REF TO ZCL_C.
LOOP AT lt_refs INTO lr_ref.
  "Sort based on lr_ref->attr1. ?
ENDLOOP.
"or can I
SORT lt_refs BY attr1.
"directly?

Answer 1

Danial, please see the following.  In the case where you want to sort your reference by an attribute within the object, you can do something like this.
report zrich_0001.
*       CLASS lcl_tab DEFINITION
class lcl_app definition.
  public section.
    data: attri type i.
    methods: constructor importing im_attri type i.
endclass.
*       CLASS lcl_tab IMPLEMENTATION
class lcl_app implementation.
  method constructor.
    attri = im_attri.
  endmethod.
endclass.
data: a_app type ref to lcl_app.
data: a_app_list type table of ref to lcl_app.
start-of-selection.
  create object a_app exporting im_attri =  3 .
  append a_app to a_app_list.
  create object a_app exporting im_attri =  2 .
  append a_app to a_app_list.
  create object a_app exporting im_attri =  1 .
  append a_app to a_app_list.
  sort a_app_list by <b>table_line->attri</b> ascending .
  check sy-subrc = 0.
Here is the documentation.
<i>
<b>
Access to Attributes with References in Internal Tables</b>
If the line type of internal tables includes reference variables as components comp, the attributes attr of the object to which the reference in a line points can be used as key values for reading, sorting and changing table rows. This is possible in the following statements:
,,LOOP AT itab ... WHERE comp->attr ...
,,READ TABLE itab ... WITH [TABLE] KEY comp->attr = ...
<b>,,SORT itab BY comp->attr ...</b>
,,DELETE itab WHERE comp->attr ...
,,MODIFY itab ... TRANSPORTING ... WHERE comp->attr ...
<b>If a table contains unstructured lines with the type of a reference variable, the attributes of the object to which a line points can be addressed using TABLE_LINE->attr.</b>
</i>
Regards,
RIch Heilman