Custom getter & setter methods in Webdynpro ABAP - Part 1

[ramakrishnappa]

Hello... Welcome :smile:

While developing complex WDA applications, we may have to have many context nodes defined and its very much required to get and set data from/to these context nodes.

For getting and setting data from/to a context node, we need to follow the below process

• Define data of type node ( element/elements )
• Get the node reference by using node names
• Get the elements using node reference
• Get data / set data using element reference or node reference based on cardinality i.e. if cardinality is 0...1, 1..1 ( structure ) 0..n, 1...n ( table )

If we have many nodes in our application, say around 10-15 context nodes, we have to repeat above steps for each read/write data access

So, its better idea to have a common method for getting data from context node / for setting data to context node.

HELPER CLASS:

You would be wondering why this HELPER CLASS is needed ?,

It very much helpful to have all common methods in a class and it can be called from any view/ controller method.Hence,it is named as helper class to my application.

I have created the below 2 static methods in class ZCL_WD_HELPER_CLASS

• GET_CTX_STAT_ATTR(  ) - Get static attributes / table data of context node
• SET_CTX_STAT_ATTR(  ) - Set static attributes / table to context node

Now, let us look at these methods signature & logic :smile:

Method: GET_CTX_STAT_ATTR(  ).

Signature:

Logic:

GET_CTX_STAT_ATTR

METHOD get_ctx_stat_attr.   DATA lo_nd                TYPE REF TO if_wd_context_node.   DATA lo_nd_struct_descr   TYPE REF TO cl_abap_structdescr.   DATA lo_nd_info           TYPE REF TO if_wd_context_node_info.   DATA lo_stat_data         TYPE REF TO data.   DATA lv_node_name         TYPE string.   DATA lv_type_name         TYPE string.   DATA lv_index             TYPE i.   DATA lo_typedescr_target  TYPE REF TO cl_abap_typedescr.   FIELD-SYMBOLS: <lt_stat_attr>     TYPE STANDARD TABLE,                  <ls_stat_attr>     TYPE any.   "----------------------------------------------------   "Purpose: Get data from context node of given controller context   "----------------------------------------------------   CLEAR: ed_error_message,           ed_stat_attr.   "===================================   "check if type of target is table   lo_typedescr_target =   cl_abap_typedescr=>describe_by_data( p_data = ed_stat_attr ).   IF lo_typedescr_target IS NOT BOUND.     RETURN.   ENDIF.   "check if context is supplied   IF io_context IS  BOUND.     lv_node_name = id_node_name.     TRANSLATE lv_node_name TO UPPER CASE.     TRY.         "read node         lo_nd = io_context->get_child_node( name = lv_node_name ).         IF lo_nd IS BOUND.           " Return if node is not dirty, and caller wants values only if dirty           IF ib_only_if_dirty = abap_true AND              lo_nd->is_changed_by_client( ) = abap_false.             RETURN.           ENDIF.           "get node info           lo_nd_info = lo_nd->get_node_info( ).           IF lo_nd_info IS BOUND.             "get the type descriptor of node             lo_nd_struct_descr =             lo_nd_info->get_static_attributes_type( ).             "check if type name is DDtype             IF lo_nd_struct_descr IS BOUND AND                lo_nd_struct_descr->is_ddic_type( ) EQ abap_true.               lv_type_name = lo_nd_struct_descr->get_relative_name( ).               "============================================               "based on node cardinality & supplied index,               " create data type & get data from context               IF lo_nd_info->is_multiple( ) EQ abap_true AND                  id_index = 0.                 "============================================                 "return if target data type is not of kind - table                 IF  lo_typedescr_target->kind NE                     lo_typedescr_target->kind_table.                   ed_error_message = 'Data mismatch against context node'.                   RETURN.                 ENDIF.                 "create data object based cardinality                 CREATE DATA lo_stat_data TYPE TABLE OF (lv_type_name).                 ASSIGN lo_stat_data->* TO <lt_stat_attr>.                 IF <lt_stat_attr> IS ASSIGNED.                   lo_nd->get_static_attributes_table(                    IMPORTING table = <lt_stat_attr> ).                   ed_stat_attr = <lt_stat_attr>.                 ENDIF.               ELSE.                 "============================================                 "return if target data type is not of kind - Structure                 IF  lo_typedescr_target->kind NE                     lo_typedescr_target->kind_struct.                   ed_error_message = 'Data mismatch against context node'.                   RETURN.                 ENDIF.                 "Prepare lv_index, based on id_index                 IF id_index EQ 0.                   lv_index = 1.                 ELSE.                   lv_index = id_index.                 ENDIF.                 "create data object based cardinality                 CREATE DATA lo_stat_data TYPE (lv_type_name).                 ASSIGN lo_stat_data->* TO <ls_stat_attr>.                 IF <ls_stat_attr> IS ASSIGNED.                   lo_nd->get_static_attributes(                    EXPORTING index = lv_index                    IMPORTING static_attributes = <ls_stat_attr> ).                   ed_stat_attr = <ls_stat_attr>.                 ENDIF.               ENDIF.             ENDIF.           ENDIF.         ELSE.           ed_error_message = 'Node does not exist in the provided context'.         ENDIF.       CATCH cx_root.                                     "#EC CATCH_ALL         ##no_handler         ed_error_message = 'Error occured during context node read'.     ENDTRY.   ELSE.     ed_error_message = 'Context is not supplied'.     RETURN.   ENDIF. ENDMETHOD.

Okay, now let us see how to use the method GET_CTX_STAT_ATTR( ) to get data from context node

Example:

Get data : Let us say we have a context node MY_NODE_T in component controller context with cardinality 0....n /1..n

DATA lt_my_node_t     TYPE wd_this->elements_my_node_t.

  DATA lv_error_message TYPE string.

  CALL METHOD zcl_wd_helper_class=>get_ctx_stat_attr

    EXPORTING

      io_context       = wd_context

      id_node_name     = 'MY_NODE_T'

*     id_index         = 0

*     ib_only_if_dirty = ABAP_FALSE

    IMPORTING

      ed_stat_attr     = lt_my_node_t

      ed_error_message = lv_error_message.

Get data : Let us say we have a context node MY_NODE_S in component controller context with cardinality 0....1 / 1...1

DATA ls_my_node_s     TYPE wd_this->element_my_node_s.

  DATA lv_error_message TYPE string.

  CALL METHOD zcl_wd_helper_class=>get_ctx_stat_attr

    EXPORTING

      io_context       = wd_context

      id_node_name     = 'MY_NODE_S'

*     id_index         = 0

*     ib_only_if_dirty = ABAP_FALSE

    IMPORTING

      ed_stat_attr     = ls_my_node_s

      ed_error_message = lv_error_message.

Continued.......

Custom getter & setter methods in Webdynpro ABAP - Part 2