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Serializing Data References

This example demonstrates serializations of data references to asXML and to asJSON.

Other versions: 7.31 | 7.40 | 7.54

Source Code

    DATA(out) = cl_demo_output=>new(
      )->begin_section( `Serialization of Data References` ).
    DATA xml  TYPE xstring.
    DATA writer TYPE REF TO cl_sxml_string_writer.

    "Data reference with named type
    out->begin_section( `Data Reference with Named Type` ).
    TYPES:
      BEGIN OF struc,
        comp1 TYPE i,
        comp2 TYPE i,
      END OF struc.
    DATA dref1 TYPE REF TO struc.
    dref1 = NEW #( comp1 = 111 comp2 = 222 ).
    out->begin_section( `asXML for Heap Reference` ).
    CALL TRANSFORMATION id SOURCE dref = dref1
                           RESULT XML xml.
    out->write_xml( xml
      )->next_section( `asJSON for Heap Reference` ).
    writer = cl_sxml_string_writer=>create(
      type = if_sxml=>co_xt_json ).
    CALL TRANSFORMATION id SOURCE dref = dref1
                           RESULT XML writer.
    out->write_json( writer->get_output( )
      )->end_section( ).

    "Data reference with technical type
    out->next_section( `Data Reference with Technical Type` ).
    DATA:
      BEGIN OF struc,
        comp1  TYPE i,
        comp2  TYPE i,
      END OF struc,
      dref2 LIKE REF TO struc.
    dref2 = NEW #( comp1 = 111 comp2 = 222 ).
    out->begin_section( `asXML for Heap Reference`
      )->begin_section( `Without Transformation Option` ).
    TRY.
        CALL TRANSFORMATION id SOURCE dref = dref2
                               RESULT XML xml.
        out->write_xml( xml ).
      CATCH cx_xslt_serialization_error INTO DATA(xml_err).
        out->write( xml_err->previous->get_text( ) ).
    ENDTRY.
    out->next_section( `With Transformation Option` ).
    CALL TRANSFORMATION id SOURCE dref = dref2
                           RESULT XML xml
                           OPTIONS technical_types = 'ignore'.
    out->write_xml( xml
      )->end_section(
      )->next_section( `asJSON for Heap Reference`
      )->begin_section( `Without Transformation Option` ).
    TRY.
        writer = cl_sxml_string_writer=>create(
          type = if_sxml=>co_xt_json ).
        CALL TRANSFORMATION id SOURCE dref = dref2
                               RESULT XML writer.
        out->write_json( writer->get_output( ) ).
      CATCH cx_xslt_serialization_error INTO DATA(json_err).
        out->write( json_err->previous->get_text( ) ).
    ENDTRY.
    out->next_section( `With Transformation Option` ).
    writer = cl_sxml_string_writer=>create(
      type = if_sxml=>co_xt_json ).
    CALL TRANSFORMATION id SOURCE dref = dref2
                           RESULT XML writer
                           OPTIONS technical_types = 'ignore'.
    out->write_json( writer->get_output( )
      )->end_section(
      )->end_section( ).

    "Stack reference
    out->next_section( `Stack Reference` ).
    DATA dref3 TYPE REF TO i.
    dref3 = REF #( 333 ).
    out->begin_section( `asXML for Stack Reference`
      )->begin_section( `Without Transformation Option` ).
    CALL TRANSFORMATION id SOURCE dref = dref3
                           RESULT XML xml.
    out->write_xml( xml
      )->next_section( `With Transformation Option` ).
    CALL TRANSFORMATION id SOURCE dref = dref3
                           RESULT XML xml
                           OPTIONS data_refs = 'heap-or-create'.
    out->write_xml( xml
      )->end_section(
      )->next_section( `asJSON for Stack Reference`
      )->begin_section( `Without Transformation Option` ).
    writer = cl_sxml_string_writer=>create(
      type = if_sxml=>co_xt_json ).
    CALL TRANSFORMATION id SOURCE dref = dref3
                           RESULT XML writer.
    out->write_json( writer->get_output( )
      )->next_section( `With Transformation Option` ).
    writer = cl_sxml_string_writer=>create(
      type = if_sxml=>co_xt_json ).
    CALL TRANSFORMATION id SOURCE dref = dref3
                           RESULT XML writer
                           OPTIONS data_refs = 'heap-or-create'.
    out->write_json( writer->get_output( )
      )->display( ).

Description

This example demonstrates the serialization of data reference variables using the identity transformation ID to the canonical formats asXML and asJSON.

  • First a data reference is serialized that points to an anonymous data object in the heap and whose dynamic type struc was created in the same program using the TYPES statement. No problems should arise from this serialization.
  • Next, however, a data reference variable is serialized that points to an anonymous data object in the heap whose dynamic type does not have a name. This is the technical type of a structure and reference to this type is made using LIKE. A data reference variable of this type cannot be serialized without taking further actions. This exception can be prevented using the transformation option technical_types, however the data reference variable is ignored.
  • Finally, a data reference variable is serialized that points to a data object in the stack. The data reference variable is ignored by default, but can be serialized using the transformation option data_refs.