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2024-07-19 14:41:34 +02:00
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21_XML_JSON.md
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@@ -11,7 +11,7 @@
- [CALL TRANSFORMATION Syntax](#call-transformation-syntax)
- [Working with JSON](#working-with-json)
- [Excursions](#excursions)
- [Serializing and Deserializing Instances of Classes](#serializing-and-deserializing-instances-of-classes)
- [Serializing and Deserializing Objects](#serializing-and-deserializing-objects)
- [Converting string \<-\> xstring](#converting-string---xstring)
- [Compressing and Decompressing Binary Data](#compressing-and-decompressing-binary-data)
- [More Information](#more-information)
@@ -676,19 +676,110 @@ xco_cp_json=>data->from_string( json_created_xco )->apply( VALUE #(
## Excursions
### Serializing and Deserializing Instances of Classes
### Serializing and Deserializing Objects
For serializing instances of classes, find more information [here](https://help.sap.com/doc/abapdocu_cp_index_htm/CLOUD/en-US/index.htm?file=abenasxml_class_instances.htm) in the ABAP Keyword Documentation. The classes must implement the `IF_SERIALIZABLE_OBJECT` interface.
- To serialize and deserialize objects (i.e. instances of classes), you can use `CALL TRANSFORMATION` statements. As a prerequisite, the classes must implement the `IF_SERIALIZABLE_OBJECT` interface.
- Find more information and examples [here](https://help.sap.com/doc/abapdocu_cp_index_htm/CLOUD/en-US/index.htm?file=abenasxml_class_instances.htm) in the ABAP Keyword Documentation.
Expand the following collapsible section to view the code of an example. To try it out, create a demo class named `zcl_some_class` and paste the code into it. After activation, choose *F9* in ADT to execute the class. This example is set up to display the results in the console.
Expand the following collapsible section to view the code of two simplified examples. To try them out, create a demo class named `zcl_some_class` and paste the code into it. After activation, choose *F9* in ADT to execute the class. The examples are set up to display output in the console.
<details>
<summary>Expand to view the details</summary>
<!-- -->
When running the class, three instances of this class are created, and two instance attributes are assigned values for output purposes. The current UTC timestamp
and a random number are retrieved and assigned. Then, the instances are serialized.
The instances are deserialized again, and the instance attributes are accessed. Their values are stored in an internal table, which is then displayed.
- When the class runs, it creates three instances, and three instance attributes are assigned values for each instance: the current UTC timestamp, a random number, and a UUID.
- These instances are then serialized and subsequently deserialized.
- The instance attributes are accessed, and their values are stored in an internal table and displayed.
**Example 1:**
- The example class implements the `IF_SERIALIZABLE_OBJECT` interface, using the standard behavior to serialize and deserialize all instance attributes (i.e. the helper methods mentioned below are not implemented).
- The values of of all deserialized instance attributes are displayed.
```abap
CLASS zcl_some_class DEFINITION
PUBLIC
FINAL
CREATE PUBLIC .
PUBLIC SECTION.
INTERFACES: if_oo_adt_classrun,
if_serializable_object.
PROTECTED SECTION.
PRIVATE SECTION.
DATA timestamp TYPE utclong.
DATA random_number TYPE i.
DATA uuid TYPE sysuuid_x16.
ENDCLASS.
CLASS zcl_some_class IMPLEMENTATION.
METHOD if_oo_adt_classrun~main.
DATA serialized_obj_tab TYPE string_table.
TYPES: BEGIN OF deserialized_obj_struc,
timestamp TYPE utclong,
random_number TYPE i,
uuid TYPE sysuuid_x16,
END OF deserialized_obj_struc.
DATA deserialized_obj_tab TYPE TABLE OF deserialized_obj_struc WITH EMPTY KEY.
"Creating objects, assigning values to instance attributes, and serializing objects
DO 3 TIMES.
DATA(oref) = NEW zcl_some_class( ).
oref->timestamp = utclong_current( ).
oref->random_number = cl_abap_random_int=>create( seed = cl_abap_random=>seed( )
min = 1
max = 100 )->get_next( ).
TRY.
oref->uuid = cl_system_uuid=>create_uuid_x16_static( ) .
CATCH cx_uuid_error.
ENDTRY.
DATA serialized_obj TYPE string.
CALL TRANSFORMATION id SOURCE obj = oref
RESULT XML serialized_obj.
APPEND serialized_obj TO serialized_obj_tab.
ENDDO.
"Deserializing objects
LOOP AT serialized_obj_tab INTO DATA(wa).
DATA deserialized_obj TYPE REF TO zcl_some_class.
CALL TRANSFORMATION id SOURCE XML wa
RESULT obj = deserialized_obj.
"Addressing instance attributes after deserialization
DATA(deserialized_timestamp) = deserialized_obj->timestamp.
DATA(deserialized_random_number) = deserialized_obj->random_number.
DATA(deserialized_uuid) = deserialized_obj->uuid.
"Adding deserialized instance attribute values to an internal table
APPEND VALUE #( timestamp = deserialized_timestamp
random_number = deserialized_random_number
uuid = deserialized_uuid
) TO deserialized_obj_tab.
ENDLOOP.
out->write( deserialized_obj_tab ).
ENDMETHOD.
ENDCLASS.
```
**Example 2:**
- The example class implements the `IF_SERIALIZABLE_OBJECT` interface, along with the `SERIALIZE_HELPER` and `DESERIALIZE_HELPER` methods.
- These methods allow you to modify the standard behavior. Both methods must be implemented together, or not at all. If neither is implemented, the standard behavior applies.
- The methods must be declared as private instance methods. The `SERIALIZE_HELPER` method only has output parameters, while `DESERIALIZE_HELPER` only has input parameters. Any parameter specified for the `SERIALIZE_HELPER` method must have an identically named and typed parameter in the `DESERIALIZE_HELPER` method.
- For example, you can implement these methods if you want to exclude certain attributes from (de)serialization.
- In the given example, one of the instance attributes is excluded from (de)serialization. As a result, the output only includes initial values for one of the attributes.
```abap
@@ -699,32 +790,19 @@ CLASS zcl_some_class DEFINITION
PUBLIC SECTION.
INTERFACES: if_oo_adt_classrun,
if_serializable_object.
if_serializable_object.
PROTECTED SECTION.
PRIVATE SECTION.
DATA timestamp TYPE utclong.
DATA random_number TYPE i.
DATA serialized_obj_tab TYPE TABLE OF xstring WITH EMPTY KEY.
TYPES: BEGIN OF deserialized_obj_struc,
timestamp TYPE utclong,
random_number TYPE i,
END OF deserialized_obj_struc.
DATA deserialized_obj_tab TYPE TABLE OF deserialized_obj_struc WITH EMPTY KEY.
DATA uuid TYPE sysuuid_x16.
METHODS:
"The following method can only have output parameters.
"For each output parameter of the serialize_helper method, you must specify
"an identically named input parameter of the deserialize_helper method
"with the same type.
"The example uses two instance attributes that are specified in the private
"visibility section.
serialize_helper EXPORTING timestamp TYPE utclong
random_number TYPE i,
"This method can only have input parameters.
deserialize_helper IMPORTING timestamp TYPE utclong
random_number TYPE i.
ENDCLASS.
@@ -733,11 +811,15 @@ CLASS zcl_some_class IMPLEMENTATION.
METHOD if_oo_adt_classrun~main.
"For demonstration purposes, 3 instances of the class are created and serialized.
"Two instance attributes are assigned values for output purposes (the current UTC timestamp
"and a random number are retrieved and assigned). The assigned values are also serialized and
"can be addressed after deserialization. The serialized instances of the class are added to an
"internal table which is processed below.
DATA serialized_obj_tab TYPE string_table.
TYPES: BEGIN OF deserialized_obj_struc,
timestamp TYPE utclong,
random_number TYPE i,
uuid TYPE sysuuid_x16,
END OF deserialized_obj_struc.
DATA deserialized_obj_tab TYPE TABLE OF deserialized_obj_struc WITH EMPTY KEY.
"Creating objects, assigning values to instance attributes, and serializing objects
DO 3 TIMES.
DATA(oref) = NEW zcl_some_class( ).
oref->timestamp = utclong_current( ).
@@ -745,47 +827,51 @@ CLASS zcl_some_class IMPLEMENTATION.
min = 1
max = 100 )->get_next( ).
DATA serialized_obj TYPE xstring.
TRY.
oref->uuid = cl_system_uuid=>create_uuid_x16_static( ) .
CATCH cx_uuid_error.
ENDTRY.
DATA serialized_obj TYPE string.
CALL TRANSFORMATION id SOURCE obj = oref
RESULT XML serialized_obj.
APPEND serialized_obj TO serialized_obj_tab.
ENDDO.
"Deserializing instances of classes from above
"For output purposes, the values of the instance attributes are added to an
"internal table.
"Deserializing objects
LOOP AT serialized_obj_tab INTO DATA(wa).
DATA deserialized_oref TYPE REF TO zcl_some_class.
DATA deserialized_obj TYPE REF TO zcl_some_class.
CALL TRANSFORMATION id SOURCE XML wa
RESULT obj = deserialized_oref.
RESULT obj = deserialized_obj.
"Addressing instance attributes after deserialization
DATA(deserialized_timestamp) = deserialized_oref->timestamp.
DATA(deserialized_random_number) = deserialized_oref->random_number.
DATA(deserialized_timestamp) = deserialized_obj->timestamp.
DATA(deserialized_random_number) = deserialized_obj->random_number.
DATA(deserialized_uuid) = deserialized_obj->uuid.
"Adding deserialized instance attribute values to an internal table
APPEND VALUE #( timestamp = deserialized_timestamp
random_number = deserialized_random_number
uuid = deserialized_uuid
) TO deserialized_obj_tab.
ENDLOOP.
"The output is intended to visualize the deserialized instance of a class
"and the values of its instance attributes that should differ from line to
"line.
out->write( deserialized_obj_tab ).
ENDMETHOD.
METHOD serialize_helper.
timestamp = me->timestamp.
random_number = me->random_number.
ENDMETHOD.
METHOD deserialize_helper.
me->timestamp = timestamp.
me->random_number = random_number.
ENDMETHOD.
METHOD serialize_helper.
timestamp = me->timestamp.
random_number = me->random_number.
ENDMETHOD.
ENDCLASS.
```
```
</details>