Error handling by Add_from_instance method

[Former Member]

Hello,

I would like to know how can we handle errors in ABAP OO by the add_from_instance method.

Kindly suggest your answers.

Regards,

Prerna.

[uwe_schieferstein]

Hello Perna

I assume that you mean the instance method from interface <b>IF_RECA_MESSAGE_LIST</b>.

The logic is quite simple. Let's assume a scenario where you have a <b>model instance</b> (containing the business logic -> <b>MVC </b>model). This model instance creates instance of others classes (e.g. for sales orders, etc.). Thus, we have a <b>composition </b>of classes.

Both the model instance and the others instances (which are customer classes) have a message handler (of TYPE REF TO if_reca_message_list). The message handler is defines as <b>public </b>and <b>read-only</b> instance attribute.

Following is some sample coding which demonstates the logic:

" We are here in a method of the model instance. We access the message handler
" using me->msg_msglist.

" The model instance has a list of object instance (e.g. me->mt_orders).
" Before processing these orders the model instance has already added
" several messages (e.g. for validation) to its message handler.

" Now the model instance processes the order instances:

  LOOP AT me->mt_orders INTO ls_order.
"   While creating the order instance they have done themselves some validation
"   an added the message to their own message handler,
"   e.g. ls_order-instance->mo_msglist.

"   Now we add the messages from the order instances to the message handler
"   of the model instance.
    CALL METHOD me->mo_msglist->add_from_instance( ls_order-instance->mo_msglist).
"   NOTE: this method has an IMPORTING parameter which allows to add
"              the messages as subnode

  ENDLOOP.

Regards

Uwe

[Former Member]

Hello,

I have a validation class which validates the data.

In the asmple logic, you have said that we have to collect these messages.

Kindly guide me as to how do I collect them.

Thanks,

Prerna

[uwe_schieferstein]

Hello Prerna

Assuming that the methods of your validation class return the message by raising an exception you can collect the messages as following:

" 1st validation

CALL METHOD mo_myclass->validate_input1

EXPORTING

...

EXCEPTIONS

error = 1

others = 2.

IF sy-subrc <> 0.

• MESSAGE ID SY-MSGID TYPE SY-MSGTY NUMBER SY-MSGNO

• WITH SY-MSGV1 SY-MSGV2 SY-MSGV3 SY-MSGV4.

" Here we collect the message that is returned in SYST

me->mo_msglist->add_from_symsg( ).

ENDIF.

" 2nd validation

CALL METHOD mo_myclass->validate_input2

EXPORTING

...

EXCEPTIONS

error = 1

others = 2.

IF sy-subrc <> 0.

• MESSAGE ID SY-MSGID TYPE SY-MSGTY NUMBER SY-MSGNO

• WITH SY-MSGV1 SY-MSGV2 SY-MSGV3 SY-MSGV4.

" Here we collect the message that is returned in SYST

me->mo_msglist->add_from_symsg( ).

ENDIF.

Regards

Uwe