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danrega
2023-12-01 12:03:04 +01:00
parent e47fb2a883
commit 2d3f6ac97b
15 changed files with 217 additions and 57 deletions
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src/zcl_demo_abap_xml_json.clas.abap
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@@ -4,12 +4,13 @@
*
* -------------------------- PURPOSE ----------------------------------
* - Example that demonstrates working with XML and JSON in ABAP.
* - The following topics are covered:
* - Converting string <-> xstring
* - The following topics are covered:*
* - Processing XML using class libraries (iXML, sXML)
* - XML Transformations using XSLT and Simple Transformations
* - CALL TRANSFORMATION syntax
* - Dealing with JSON data
* - Excursions: Converting string <-> xstring, compressing and
* decompressing binary data
*
* ----------------------- GETTING STARTED -----------------------------
* - Open the class with the ABAP development tools for Eclipse (ADT).
@@ -47,7 +48,10 @@ CLASS zcl_demo_abap_xml_json DEFINITION
CREATE PUBLIC .
PUBLIC SECTION.
INTERFACES if_oo_adt_classrun.
INTERFACES: if_oo_adt_classrun,
"This interface is implemented for serializing and
"deserialzing instances of classes (objects).
if_serializable_object.
CLASS-METHODS class_constructor.
PROTECTED SECTION.
@@ -59,6 +63,26 @@ CLASS zcl_demo_abap_xml_json DEFINITION
TYPES c50_tab_type TYPE TABLE OF c50 WITH EMPTY KEY.
TYPES x30 TYPE x LENGTH 30.
TYPES x30_tab_type TYPE TABLE OF x30 WITH EMPTY KEY.
"The following instance attribues and methods are used for serializing and
"deserialzing instances of classes (objects)
DATA: attr_string_a TYPE string,
attr_string_b TYPE string,
attr_concat_string TYPE string,
attr_lowercase_str TYPE string.
METHODS: concatenate_string,
lowercase_string,
"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.
serialize_helper EXPORTING attr_string_a TYPE string
attr_string_b TYPE string
attr_concat_string TYPE string,
"This method can only have input parameters.
deserialize_helper IMPORTING attr_string_a TYPE string
attr_string_b TYPE string
attr_concat_string TYPE string.
ENDCLASS.
@@ -67,7 +91,7 @@ CLASS zcl_demo_abap_xml_json IMPLEMENTATION.
METHOD if_oo_adt_classrun~main.
out->write( |ABAP Cheat Sheet Example: XML\n\n| ).
out->write( |ABAP Cheat Sheet Example: Working with XML and JSON in ABAP\n\n| ).
out->write( |1) Excursion: Converting string <-> xstring| ).
"In the following examples, many operations are performed using binary data.
"This excursion shows the conversion of string to xstring and the other way round
@@ -869,9 +893,7 @@ CLASS zcl_demo_abap_xml_json IMPLEMENTATION.
************************************************************************
out->write( zcl_demo_abap_aux=>heading( `17) References` ) ).
"The example demonstrates a data reference. For (serializable) object references,
"check the ABAP Keyword Documentation.
out->write( zcl_demo_abap_aux=>heading( `17) Data References` ) ).
DATA(dref_a) = NEW i( 123 ).
@@ -896,7 +918,75 @@ CLASS zcl_demo_abap_xml_json IMPLEMENTATION.
************************************************************************
out->write( zcl_demo_abap_aux=>heading( `18) CALL TRANSFORMATION Syntax: Specifying Transformations` ) ).
out->write( zcl_demo_abap_aux=>heading( `18) Object References` ) ).
"The following example demonstrates the serialization and deserialization of
"instances of classes (objects). For example, to serialize instance attributes,
"classes must implement the if_serializable_object interface. By default, all instance
"attributes of an object are serialized, regardless of their visibility section.
"However, you can change this behavior using the serialize_helper and deserialize_helper
"instance methods. As a result of the transformation, you get an asXML representation of
"the object.
"The example is implemented as follows:
"- The class implements the if_serializable_object interface.
"- There are 4 instance attributes of type string.
"- There are two instance methods:
" - One method concatenates two of the strings and assigns the resulting string to
" another string.
" - Another method concatenates two strings and converts the string to lowercase.
" The result is assigned to another string.
"- Serialization preserves instance attribute values in the asXML representation of the
" object.
"- During deserialization, the instance attribute values are transformed back and can
" be accessed.
"- The example includes the implementation of the serialize_helper and deserialize_helper
" instance methods. Without implementation, all instance attributes would be
" serialized/deserialized. The sample implementation limits serialization/deserialization.
" The fourth instance attribute, which is converted to a lowercase string when calling the
" method, is not part of the serialization/deserialization. See the implementation of the
" serialize_helper and deserialize_helper instance methods. They explicitly specify what
" to serialize and deserialize.
"- Note: For each output parameter of the serialize_helper method, you must specify an
" identically-named input parameter of the deserialize_helper method. The parameters must
" have the same type.
DATA(oref_a) = NEW zcl_demo_abap_xml_json( ).
oref_a->attr_string_a = `AB`.
oref_a->attr_string_b = `AP`.
oref_a->concatenate_string( ).
oref_a->lowercase_string( ).
out->write( `Value of instance attribute attr_lowercase_str for the created instance (before serialization/deserialization):` ).
out->write( oref_a->attr_lowercase_str ).
out->write( |\n| ).
"ABAP -> XML
DATA xml_oref_a TYPE xstring.
CALL TRANSFORMATION id SOURCE oref = oref_a
RESULT XML xml_oref_a.
DATA(conv_xml_oref_a) = cl_abap_conv_codepage=>create_in( )->convert( xml_oref_a ).
out->write( `ABAP -> XML` ).
out->write( format( conv_xml_oref_a ) ).
out->write( |\n| ).
"XML -> ABAP
DATA oref_b LIKE oref_a.
CALL TRANSFORMATION id SOURCE XML xml_oref_a
RESULT oref = oref_b.
out->write( `XML -> ABAP` ).
out->write( oref_b->attr_string_a ).
out->write( oref_b->attr_string_b ).
out->write( oref_b->attr_concat_string ).
out->write( |\n| ).
IF oref_b->attr_lowercase_str IS INITIAL.
out->write( `The instance attribute attr_lowercase_str is initial. The serialization/deserialization is restricted.` ).
ENDIF.
************************************************************************
out->write( zcl_demo_abap_aux=>heading( `19) CALL TRANSFORMATION Syntax: Specifying Transformations` ) ).
"As already covered in the examples above, transformations are specified after
"CALL TRANSFORMATION. They are either ...
@@ -931,7 +1021,7 @@ CLASS zcl_demo_abap_xml_json IMPLEMENTATION.
************************************************************************
out->write( zcl_demo_abap_aux=>heading( `19) CALL TRANSFORMATION Syntax: Sources of Transformations` ) ).
out->write( zcl_demo_abap_aux=>heading( `20) CALL TRANSFORMATION Syntax: Sources of Transformations` ) ).
"The following examples use the predefined identity transformation ID.
"The result is asXML data and stored in a variable of type xstring.
"Multiple options and variants are possible. The examples cover a selection.
@@ -1060,7 +1150,7 @@ CLASS zcl_demo_abap_xml_json IMPLEMENTATION.
*************************************************************************
out->write( zcl_demo_abap_aux=>heading( `20) CALL TRANSFORMATION Syntax: Results of Transformations` ) ).
out->write( zcl_demo_abap_aux=>heading( `21) CALL TRANSFORMATION Syntax: Results of Transformations` ) ).
"As in the examples above, the predefined identity transformation is used here.
"Creating demo XML data to be used in the example as the source.
@@ -1171,7 +1261,7 @@ CLASS zcl_demo_abap_xml_json IMPLEMENTATION.
************************************************************************
out->write( zcl_demo_abap_aux=>heading( `21) Dealing with JSON Data` ) ).
out->write( zcl_demo_abap_aux=>heading( `22) Dealing with JSON Data` ) ).
"Note: When the identity transformation ID is used, the format is asJSON.
"Elementary type
@@ -1336,6 +1426,45 @@ CLASS zcl_demo_abap_xml_json IMPLEMENTATION.
DATA(xml2json_sxml) = cl_abap_conv_codepage=>create_in( )->convert( json_wr->get_output( ) ).
out->write( `XML -> JSON using sXML` ).
out->write( xml2json_sxml ).
************************************************************************
out->write( zcl_demo_abap_aux=>heading( `23) Excursion: Compressing and Decompressing Binary Data` ) ).
"You may want to process or store binary data. The data can be very large.
"You can compress the data in gzip format and decompress it for further processing using
"the cl_abap_gzip class. Check out appropriate exceptions to be caught. The simple example
"just specifies cx_root. See the class documentation for more information.
"This example uses a data object of type xstring from a previous example.
"Compressing binary data
DATA xstr_comp TYPE xstring.
TRY.
cl_abap_gzip=>compress_binary( EXPORTING raw_in = xml_oref_a
IMPORTING gzip_out = xstr_comp ).
CATCH cx_root INTO DATA(error_comp).
out->write( error_comp->get_text( ) ).
ENDTRY.
"Decompressing binary data
DATA xstr_decomp TYPE xstring.
TRY.
cl_abap_gzip=>decompress_binary( EXPORTING gzip_in = xstr_comp
IMPORTING raw_out = xstr_decomp ).
CATCH cx_root INTO DATA(error_decomp).
out->write( error_decomp->get_text( ) ).
ENDTRY.
"Checking the xstring length of the variables used and comparing result
DATA(strlen_original_xstring) = xstrlen( xml_oref_a ).
out->write( |Length of original binary data object: { strlen_original_xstring }| ).
DATA(strlen_comp) = xstrlen( xstr_comp ).
out->write( |Length of compressed binary data object: { strlen_comp }| ).
DATA(strlen_decomp) = xstrlen( xstr_decomp ).
out->write( |Length of decompressed binary data object: { strlen_decomp }| ).
IF xml_oref_a = xstr_decomp.
out->write( `The decompressed binary data object has the same value as the original binary data object.` ).
ENDIF.
ENDMETHOD.
METHOD format.
TRY.
@@ -1359,4 +1488,24 @@ CLASS zcl_demo_abap_xml_json IMPLEMENTATION.
zcl_demo_abap_aux=>fill_dbtabs( ).
ENDMETHOD.
ENDCLASS.
METHOD concatenate_string.
attr_concat_string = attr_string_a && attr_string_b.
ENDMETHOD.
METHOD deserialize_helper.
me->attr_string_a = attr_string_a.
me->attr_string_b = attr_string_b.
me->attr_concat_string = attr_concat_string.
ENDMETHOD.
METHOD serialize_helper.
attr_string_a = me->attr_string_a.
attr_string_b = me->attr_string_b.
attr_concat_string = me->attr_concat_string.
ENDMETHOD.
METHOD lowercase_string.
attr_lowercase_str = to_lower( attr_string_a && attr_string_b ).
ENDMETHOD.
ENDCLASS.