If standard class functionality does not fit your requirements there are two ways how you can adapt it to your needs:
- Use a local copy of the class /UI2/CL_JSON and modify logic directly by changing the original code.
- Inherit from class /UI2/CL_JSON and override methods where another logic is required.
The advantage of the first approach is that you are completely free in what you may change and have full control of the class lifecycle. The disadvantage is that you must merge your changes with /UI2/CL_JSON updates.
For the second approach, you can use /UI2/CL_JSON directly (the prerequisite is the latest version of note 2330592), you do not need to care about the merge but can override only some methods. The methods are:
IS_COMPRESSIBLE is called to check, if the given type output may be suppressed during ABAP to JSON serialization when a value is initial.
- > TYPE_DESCR (ref to CL_ABAP_TYPEDESCR) – value type
- < RV_COMPRESS (bool) – compress initial value The default implementation of the method allows compressing any initial value.
PRETTY_NAME – called to format ABAP field name written to JSON or deserialized from JSON to ABAP field, when the pretty_name parameter of SERIALIZE/DESERIALIZE method equal to PRETTY_MODE-CAMEL_CASE.
- > IN (CSEQUENCE) – Field name to pretty print.
- < OUT (STRING) – Pretty printed field name The default implementation applies camelCase formatting using the “” symbol. To output, the “” symbol, use the double “__” symbol in the field name.
PRETTY_NAME_EX – called to format ABAP field name written to JSON or deserialized from JSON to ABAP field, when the pretty_name parameter of SERIALIZE/DESERIALIZE method equal to PRETTY_MODE-EXTENDED.
- > IN (CSEQUENCE) – Field name to pretty print.
- < OUT (STRING) – Pretty printed field name The default implementation does the same as PRETTY_NAME, plus converting special characters "!#$%&*-~/:|@.".
DUMP_INT - called for recursive serialization of complex ABAP data objects (structure, class, table) into JSON string
- > DATA (DATA) – Any data to serialize.
- > TYPE_DESCR (ref to CL_ABAP_TYPEDESCR, optional) – Type of data provided
- < R_JSON (JSON) – serialized JSON value
DUMP_TYPE - called for serialization of elementary ABAP data type (string, boolean, timestamp, etc) into the JSON attribute value. Overwrite it if you, for example, want to apply data output data conversion of currency rounding
- > DATA (DATA) – Any data to serialize
- > TYPE_DESCR (ref to CL_ABAP_TYPEDESCR) – Type of data provided
- < R_JSON (JSON) – serialized JSON value
RESTORE - called for deserializing JSON objects into ABAP structures
- > JSON (JSON) – JSON string to deserialize
- > LENGTH (I) – Length of the JSON string
- > TYPE_DESCR (ref to CL_ABAP_TYPEDESCR, optional) – Type of changing data provided
- > FIELD_CACHE (type T_T_FIELD_CACHE, optional) – Cache of ABAP data fields with type information
- <> DATA (type DATA, optional) – ABAP data object to fill
- <> OFFSET (I) – parsing start point in JSON string
RESTORE_TYPE - called to deserialize simple JSON attributes and JSON arrays
- > JSON (JSON) – JSON string to deserialize
- > LENGTH (I) – Length of the JSON string
- > TYPE_DESCR (ref to CL_ABAP_TYPEDESCR, optional) – Type of changing data provided
- > FIELD_CACHE (type T_T_FIELD_CACHE, optional) – Cache of ABAP data fields with type information
- <> DATA (type DATA, optional) – ABAP data object to fill
- <> OFFSET (I) – parsing start point in JSON string
CLASS_CONSTRUCTOR - used to initialize static variables. You can not overwrite it but implement your class constructor that adapts default globals. For example, add boolean types to be recognized during serialization/deserialization.
SERIALIZE/DESERIALIZE - these methods are static and cannot be redefined. Methods are helpers for a consumption code, hiding the construction of the class instance and further *_INT calls. So, if you would like to use something similar, in your custom class, you need to copy the mentioned methods to new ones e,g *_EX and overwrite there /UI2/CL_JSON type to your custom class name. And use these methods instead of standard.
Extension using inheritance:
CLASS lc_json_custom DEFINITION FINAL INHERITING FROM /ui2/cl_json.
PUBLIC SECTION.
CLASS-METHODS:
class_constructor,
deserialize_ex IMPORTING json TYPE json OPTIONAL
pretty_name TYPE pretty_name_mode DEFAULT pretty_mode-none
CHANGING data TYPE data,
serialize_ex IMPORTING data TYPE data
compress TYPE bool DEFAULT c_bool-false
pretty_name TYPE pretty_name_mode DEFAULT pretty_mode-none
RETURNING value(r_json) TYPE json.
PROTECTED SECTION.
METHODS:
is_compressable REDEFINITION,
pretty_name REDEFINITION,
dump_type REDEFINITION.
ENDCLASS. "lc_json_custom DEFINITION
CLASS lc_json_custom IMPLEMENTATION.
METHOD class_constructor.
CONCATENATE mc_bool_types `\TYPE=/UI2/BOOLEAN` INTO mc_bool_types.
ENDMETHOD. "class_constructor
METHOD is_compressable.
IF type_descr->absolute_name EQ `\TYPE=STRING` OR name EQ `INITIAL`.
rv_compress = abap_false.
ELSE.
rv_compress = abap_true.
ENDIF.
ENDMETHOD. "is_compressable
METHOD pretty_name.
out = super->pretty_name( in ).
CONCATENATE out 'Xxx' INTO out.
ENDMETHOD. "pretty_name
METHOD dump_type.
DATA: is_ddic TYPE abap_bool,
ddic_field TYPE dfies.
is_ddic = type_descr->is_ddic_type( ).
IF is_ddic EQ abap_true.
ddic_field = type_descr->get_ddic_field( ).
IF mv_ts_as_iso8601 EQ c_bool-true AND ddic_field-domname EQ `TZNTSTMPL`.
r_json = data.
CONCATENATE `"` r_json(4) `-` r_json+4(2) `-` r_json+6(2) `T` r_json+8(2) `:` r_json+10(2) `:` r_json+12(2) `.` r_json+15(7) `Z"` INTO r_json.
RETURN.
ENDIF.
ENDIF.
IF mv_ts_as_iso8601 EQ c_bool-true AND type_descr->absolute_name EQ `\TYPE=LCM_CHANGED_ON`.
r_json = data.
CONCATENATE `"` r_json(4) `-` r_json+4(2) `-` r_json+6(2) `T` r_json+8(2) `:` r_json+10(2) `:` r_json+12(2) `.` r_json+15(7) `Z"` INTO r_json.
RETURN.
ENDIF.
r_json = super->dump_type( data = data type_descr = type_descr convexit = convexit ).
ENDMETHOD. "dump_type
METHOD serialize_ex.
DATA: lo_json TYPE REF TO lc_json_custom.
CREATE OBJECT lo_json
EXPORTING
compress = compress
pretty_name = pretty_name
assoc_arrays = abap_true
assoc_arrays_opt = abap_true
expand_includes = abap_true
numc_as_string = abap_true
ts_as_iso8601 = abap_true.
r_json = lo_json->serialize_int( data = data ).
ENDMETHOD. "serialize_ex
METHOD deserialize_ex.
DATA: lo_json TYPE REF TO lc_json_custom.
IF json IS NOT INITIAL.
CREATE OBJECT lo_json
EXPORTING
pretty_name = pretty_name
assoc_arrays = abap_true
assoc_arrays_opt = abap_true.
TRY .
lo_json->deserialize_int( EXPORTING json = json CHANGING data = data ).
CATCH cx_sy_move_cast_error.
ENDTRY.
ENDIF.
ENDMETHOD. "deserialize_ex
ENDCLASS. "lc_json_custom IMPLEMENTATION
TYPES:
BEGIN OF tp_s_data,
tribool TYPE lc_json_custom=>tribool,
bool TYPE lc_json_custom=>bool,
str1 TYPE string,
str2 TYPE string,
initial TYPE i,
END OF tp_s_data.
DATA: ls_exp TYPE tp_s_data,
ls_act LIKE ls_exp,
lo_json_custom TYPE REF TO lc_json_custom,
lv_json_custom TYPE lc_json_custom=>json.
ls_exp-tribool = lc_json_custom=>c_tribool-false.
ls_exp-bool = lc_json_custom=>c_bool-false.
ls_exp-str1 = ''.
ls_exp-str2 = 'ABC'.
ls_exp-initial = 0.
CREATE OBJECT lo_json_custom
EXPORTING
compress = abap_true
pretty_name = lc_json_custom=>pretty_mode-camel_case.
lv_json_custom = lo_json_custom->serialize_int( data = ls_exp ).
lo_json_custom->deserialize_int( EXPORTING json = lv_json_custom CHANGING data = ls_act ).
" alternative way
lc_json_custom=>deserialize_ex( EXPORTING json = lv_json_custom CHANGING data = ls_act ).
cl_aunit_assert=>assert_equals( act = ls_act exp = ls_exp msg = 'Custom pretty name fails!' ).
WRITE / lv_json_custom.Results in the following JSON:
{
"triboolXxx": false,
"str1Xxx": "",
"str2Xxx": "ABC",
"initialXxx": 0
}