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2
01_Internal_Tables.md
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@@ -470,7 +470,7 @@ APPEND INITIAL LINE TO itab.
INSERT INITIAL LINE INTO TABLE itab.
```
**Adding a line and assignin the added line to a field symbol or data reference variable**.
**Adding a line and assigning the added line to a field symbol or data reference variable**.
```abap
"When inserting single lines, you can specify the optional additions
"ASSIGNING and REFERENCE INTO. If the insertion is successful, the

134
04_ABAP_Object_Orientation.md
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@@ -14,13 +14,20 @@
- [Creating the Visibility Sections](#creating-the-visibility-sections)
- [Defining Components](#defining-components)
- [Working with Objects and Components](#working-with-objects-and-components)
- [Declaring Reference Variables](#declaring-reference-variables)
- [Creating Objects](#creating-objects)
- [Assigning Reference Variables](#assigning-reference-variables)
- [Accessing Attributes](#accessing-attributes)
- [Calling Methods](#calling-methods)
- [Method Chaining](#method-chaining)
- [Self-Reference me](#self-reference-me)
- [Notes on Inheritance](#notes-on-inheritance)
- [Notes on Polymorphism and Casting](#notes-on-polymorphism-and-casting)
- [Notes on Interfaces](#notes-on-interfaces)
- [Additional Notes](#additional-notes)
- [Excursions](#excursions)
- [Friendship](#friendship)
- [Events](#events)
- [Excursion: Factory Methods and Singletons as Design Patterns](#excursion-factory-methods-and-singletons-as-design-patterns)
- [Factory Methods and Singletons as Design Patterns](#factory-methods-and-singletons-as-design-patterns)
- [More Information](#more-information)
- [Executable Example](#executable-example)
@@ -293,7 +300,7 @@ ENDCLASS.
(also known as
[signature](https://help.sap.com/doc/abapdocu_cp_index_htm/CLOUD/en-US/index.htm?file=abensignature_glosry.htm "Glossary Entry"))
with which methods can get values to work with when being called and pass values
back to the caller.
back to the caller (see the notes on formal and actual parameters below).
- [Static
methods](https://help.sap.com/doc/abapdocu_cp_index_htm/CLOUD/en-US/index.htm?file=abenstatic_method_glosry.htm "Glossary Entry")
can only access static attributes of a class and trigger static
@@ -329,7 +336,10 @@ In the simplest form, methods can have no parameter at all. Apart from that, met
[generic](https://help.sap.com/doc/abapdocu_cp_index_htm/CLOUD/en-US/index.htm?file=abengeneric_data_type_glosry.htm "Glossary Entry")
or
[complete](https://help.sap.com/doc/abapdocu_cp_index_htm/CLOUD/en-US/index.htm?file=abencomplete_data_type_glosry.htm "Glossary Entry")
type.
type. Examples:
> - `fp` is the formal parameter that has a complete type: `... meth IMPORTING fp TYPE string ...`
> - `gen` is the formal parameter that has a generic type: `... meth IMPORTING gen TYPE any ...`
> - Find more information about generic types also in the [Data Types and Data Objects](16_Data_Types_and_Objects.md#generic-types) cheat sheet.
> - This formal parameter includes the specification of how the
value passing should happen. Parameters can be [passed by
reference](https://help.sap.com/doc/abapdocu_cp_index_htm/CLOUD/en-US/index.htm?file=abenpass_by_reference_glosry.htm "Glossary Entry")
@@ -420,11 +430,18 @@ CLASS local_class DEFINITION.
stat_meth3 IMPORTING VALUE(m) TYPE i, "pass by value
stat_meth4 IMPORTING REFERENCE(n) TYPE i, "pass by reference
stat_meth5 IMPORTING o TYPE i, "same as n; the specification of REFERENCE(...) is optional
stat_meth6 RETURNING VALUE(p) TYPE, "pass by value once more (note: it's the only option for returning parameters)
stat_meth6 RETURNING VALUE(p) TYPE i, "pass by value once more (note: it's the only option for returning parameters)
"OPTIONAL/DEFAULT additions
stat_meth7 IMPORTING q TYPE i DEFAULT 123
r TYPE i OPTIONAL.
r TYPE i OPTIONAL,
"The examples above use a complete type for
"the parameter specification. Generic types
"are possible.
stat_meth8 IMPORTING s TYPE any "Any data type
t TYPE any table "Any internal table type
u TYPE clike. "Character-like types (c, n, string, d, t and character-like flat structures)
ENDCLASS.
@@ -441,7 +458,7 @@ ENDCLASS.
## Working with Objects and Components
**Declaring reference variables**:
### Declaring Reference Variables
- To create an object, a [reference variable](https://help.sap.com/doc/abapdocu_cp_index_htm/CLOUD/en-US/index.htm?file=abenreference_variable_glosry.htm "Glossary Entry")
must be declared.
- Such an [object reference
@@ -455,7 +472,9 @@ DATA: ref1 TYPE REF TO local_class,
ref3 LIKE ref1.
```
**Creating objects**:
<p align="right"><a href="#top">⬆️ back to top</a></p>
### Creating Objects
- Using the instance operator
[`NEW`](https://help.sap.com/doc/abapdocu_cp_index_htm/CLOUD/en-US/index.htm?file=abenconstructor_expression_new.htm),
@@ -494,7 +513,10 @@ DATA(ref2) = NEW some_class( ). "Reference variable declared inline, explic
"CREATE OBJECT ref4 TYPE some_class. "Corresponds to the result of the expression above
```
**Assigning reference variables**: To assign or copy
<p align="right"><a href="#top">⬆️ back to top</a></p>
### Assigning Reference Variables
To assign or copy
reference variables, use the [assignment
operator](https://help.sap.com/doc/abapdocu_cp_index_htm/CLOUD/en-US/index.htm?file=abenassignment_operator_glosry.htm "Glossary Entry")
`=`. In the example below, both object reference variables have the same
@@ -510,6 +532,8 @@ ref1 = NEW #( ).
ref2 = ref1.
```
More examples for dealing with object reference variables:
**Overwriting reference variables**: An [object
reference](https://help.sap.com/doc/abapdocu_cp_index_htm/CLOUD/en-US/index.htm?file=abenobject_reference_glosry.htm "Glossary Entry")
is overwritten when a new object is created with a reference variable
@@ -545,7 +569,9 @@ CLEAR ref.
> Objects use up space in the memory and should therefore be
cleared if they are no longer needed. However, the [garbage collector](https://help.sap.com/doc/abapdocu_cp_index_htm/CLOUD/en-US/index.htm?file=abengarbage_collector_glosry.htm "Glossary Entry") is called periodically and automatically by the [ABAP runtime framework](https://help.sap.com/doc/abapdocu_cp_index_htm/CLOUD/en-US/index.htm?file=abenabap_runtime_frmwk_glosry.htm "Glossary Entry") and clears all objects without any reference.
**Accessing attributes**:
<p align="right"><a href="#top">⬆️ back to top</a></p>
### Accessing Attributes
- Instance attributes: Accessed using
the [object component selector](https://help.sap.com/doc/abapdocu_cp_index_htm/CLOUD/en-US/index.htm?file=abenobject_component_select_glosry.htm "Glossary Entry")
`->` via a reference variable.
@@ -572,7 +598,9 @@ DATA dobj1 TYPE some_class=>some_type.
DATA dobj2 LIKE some_class=>some_static_attribute.
```
**Calling methods**:
<p align="right"><a href="#top">⬆️ back to top</a></p>
### Calling Methods
- Similar to accessing attributes, instance
methods are called using `->` via a reference variable.
- Static
@@ -580,11 +608,8 @@ methods are called using `=>` via the class name. When used
within the class in which it is declared, the static method can also be
called without `class_name=>...`.
- When methods are called, the (non-optional) parameters must be specified within parentheses.
- You might also stumble on method
calls with [`CALL METHOD`](https://help.sap.com/doc/abapdocu_cp_index_htm/CLOUD/en-US/index.htm?file=abapcall_method_static.htm)
statements in older programs. It should no longer be used, however, `CALL METHOD` statements are the
only option in the context of dynamic programming.
- You might also stumble on method calls with [`CALL METHOD`](https://help.sap.com/doc/abapdocu_cp_index_htm/CLOUD/en-US/index.htm?file=abapcall_method_static.htm)
statements. These statements should no longer be used. Note that `CALL METHOD` statements are the only option in the context of [dynamic programming](06_Dynamic_Programming.md). Therefore, `CALL METHOD` statements should be reserved for dynamic method calls.
Examples for instance method calls and static method calls:
@@ -642,13 +667,13 @@ class_name=>meth( CHANGING g = h ).
"Calling (static) methods having a returning parameter.
"Basically, they do the same as methods with exporting parameters
"but they are way more versatile and you save lines of code.
"but they are way more versatile, and you can save lines of code.
"They do not need temporary variables.
"In the example, the return value is stored in a variable declared inline.
"i and k are importing parameters
DATA(result) = class_name=>meth( i = j k = l )
DATA(result) = class_name=>meth( i = j k = l ).
"They can be used with other statements, e. g. logical expressions.
"In the example below, the assumption is that the returning parameter is of type i.
@@ -659,17 +684,78 @@ ENDIF.
"They enable method chaining.
"The example shows a method to create random integer values.
"The methods have a returning parameter.
DATA(random_no) = cl_abap_random_int=>create( )->get_next( ).
"Receiving parameter: Available in methods defined with a returning parameter;
"RECEIVING parameter: Available in methods defined with a returning parameter;
"used in standalone method calls only.
"In the snippet, m is the returning parameter; n stores the result.
class_name=>meth( EXPORTING i = j k = l RECEIVING m = DATA(n) ).
```
**Self-Reference me**
<p align="right"><a href="#top">⬆️ back to top</a></p>
### Method Chaining
As shown in the previous example, method chaining is possible for functional method calls (i.e. methods that have exactly one return value declared with `RETURNING`) at appropriate read positions. In this case, the method's return value is used as an ABAP operand.
A chained method call can consist of multipled functional methods that are linked using component selectors `->`. The return values of each method are references to the next method.
```abap
"The following example demonstrates method chaining
"The following class creates random integers. Find more information in the
"class documentation.
"Both methods have returning parameters specified.
DATA(some_int1) = cl_abap_random_int=>create( seed = cl_abap_random=>seed( )
min = 1
max = 10 )->get_next( ).
"Getting to the result as above - not using method chaining and inline declarations.
DATA some_int2 TYPE i.
DATA dref TYPE REF TO cl_abap_random_int.
dref = cl_abap_random_int=>create( seed = cl_abap_random=>seed( )
min = 1
max = 10 ).
some_int2 = dref->get_next( ).
"Using the RECEIVING parameter in a standalone method call
DATA some_int3 TYPE i.
dref->get_next( RECEIVING value = some_int3 ).
"IF statement that uses the return value in a read position
IF cl_abap_random_int=>create( seed = cl_abap_random=>seed( )
min = 1
max = 10 )->get_next( ) < 5.
... "The random number is lower than 5.
ELSE.
... "The random number is greater than 5.
ENDIF.
"Examples using classes of the XCO library (see more information in the
"ABAP for Cloud Development and Misc ABAP Classes cheat sheets), in which
"multiple chained method calls can be specified. Each of the methods
"has a returning parameter specified.
"In the following example, 1 hour is added to the current time.
DATA(add1hour) = xco_cp=>sy->time( xco_cp_time=>time_zone->user )->add( iv_hour = 1 )->as( xco_cp_time=>format->iso_8601_extended )->value.
"In the following example, a string is converted to xstring using a codepage
DATA(xstr) = xco_cp=>string( `Some string` )->as_xstring( xco_cp_character=>code_page->utf_8 )->value.
"In the following example, JSON data is created. First, a JSON data builder
"is created. Then, using different methods, JSON data is added. Finally,
"the JSON data is turned to a string.
DATA(json) = xco_cp_json=>data->builder( )->begin_object(
)->add_member( 'CarrierId' )->add_string( 'DL'
)->add_member( 'ConnectionId' )->add_string( '1984'
)->add_member( 'CityFrom' )->add_string( 'San Francisco'
)->add_member( 'CityTo' )->add_string( 'New York'
)->end_object( )->get_data( )->to_string( ).
```
<p align="right"><a href="#top">⬆️ back to top</a></p>
### Self-Reference me
When implementing instance methods, you can optionally make use of the implicitly available object reference variable [`me`](https://help.sap.com/doc/abapdocu_cp_index_htm/CLOUD/en-US/index.htm?file=abenme.htm) which is always available at runtime and points to the respective object itself. You can use it to refer to components of the instance of a particular class:
``` abap
@@ -1066,7 +1152,7 @@ i_ref = NEW class( ).
<p align="right"><a href="#top">⬆️ back to top</a></p>
## Additional Notes
## Excursions
### Friendship
@@ -1154,7 +1240,7 @@ SET HANDLER handler3.
<p align="right"><a href="#top">⬆️ back to top</a></p>
### Excursion: Factory Methods and Singletons as Design Patterns
### Factory Methods and Singletons as Design Patterns
In object-oriented programming, there a plenty of design patterns. Covering these ones here to get a rough idea: factory methods and singletons. Both are relevant if you want to restrict or control the instantiation of a class by external users of this class.

63
05_Constructor_Expressions.md
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@@ -1507,25 +1507,68 @@ DATA(it11) = VALUE itab_type( FOR wa IN itab USING KEY primary_key ( col1 = wa-c
*ccct 9 13
"---------- Conditional iterations ----------
"Notes:
"- When used with VALUE/NEW for internal tables: New table lines are created in
" iteration steps and added to result
"- When used with REDUCE (as shown below): Reduction result is created in iteration steps
"- Regarding the THEN addition:
" - Must be specified if the iteration variable specified after FOR is not a numeric data
" type and not of type d/t
" - If the iteration variable is a numeric type/type d or t, THEN is optional. If THEN
" is not specified, the iteration variable is implicitly incremented by 1.
"FOR ... WHILE ...
"FOR ... WHILE ...
"Implicit incrementing of the iteration variable
DATA(it12) = VALUE itab_type( FOR x = 1 WHILE x < 4
( col1 = x col2 = x + 1 col3 = x + 2 ) ).
*COL1 COL2 COL3
* 1 2 3
* 2 3 4
* 3 4 5
* 1 2 3
* 2 3 4
* 3 4 5
"The following example corresponds to the previous one. Here, THEN
"is explicitly specified.
DATA(it13) = VALUE itab_type( FOR x = 1 THEN x + 1 WHILE x < 4
( col1 = x col2 = x + 1 col3 = x + 2 ) ).
"THEN explicitly specified
DATA(it14) = VALUE itab_type( FOR x = 1 THEN x + 2 WHILE x < 8
( col1 = x col2 = x + 1 col3 = x + 2 ) ).
*COL1 COL2 COL3
* 1 2 3
* 3 4 5
* 5 6 7
* 7 8 9
"THEN addition is required for non-numeric data types of the iteration
"variable
DATA(it15) = VALUE itab_type( FOR str = `x` THEN str && str WHILE strlen( str ) < 5
( col1 = str col2 = strlen( str ) + 1 col3 = strlen( str ) + 2 ) ).
*COL1 COL2 COL3
*x 2 3
*xx 3 4
*xxxx 5 6
"FOR ... UNTIL ...
"The THEN addition is also possible for ... WHILE ...
DATA(it13) = VALUE itab_type( FOR y = 31 THEN y - 10 UNTIL y < 10
DATA(it16) = VALUE itab_type( FOR y = 10 UNTIL y > 12
( col1 = y col2 = y + 1 col3 = y + 2 ) ).
*COL1 COL2 COL3
* 31 32 33
* 21 22 23
* 11 12 13
* 10 11 12
* 11 12 13
* 12 13 14
"THEN explicitly specified
DATA(it17) = VALUE itab_type( FOR y = 31 THEN y - 10 UNTIL y < 10
( col1 = y col2 = y + 1 col3 = y + 2 ) ).
*COL1 COL2 COL3
* 31 32 33
* 21 22 23
* 11 12 13
```
<p align="right"><a href="#top">⬆️ back to top</a></p>
@@ -1689,7 +1732,7 @@ DATA(it_val_2) = VALUE string_table(
*b: 7, 8 / 9, 10
*c: 11, 12
"Constucting a result using REDUCE
"Constructing a result using REDUCE
"The example is similar to the previous one by filling a string table.
"The example uses a group key expression specified after GROUP BY.
"In the group key expression, additional components of a structured

2
08_EML_ABAP_for_RAP.md
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@@ -746,7 +746,7 @@ DATA rep TYPE RESPONSE FOR REPORTED entity.
### Components of BDEF Derived Types
Many of the BDEF derived types contain components of CDS entities like
key and data fields that retain their original line type, for example, a
key and data fields that retain their original data type, for example, a
messenger table typed with `TYPE TABLE FOR CREATE`. Certainly,
if an instance is to be created, key and field values of a RAP BO
instance are of relevance.

7
16_Data_Types_and_Objects.md
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@@ -336,7 +336,7 @@ FIELD-SYMBOLS:
<xsequence> TYPE xsequence, "Byte-like (x, xstring)
"Numeric types
<decfloat> TYPE decfloat, "decfloat16, decfloat34)
<decfloat> TYPE decfloat, "decfloat16, decfloat34
<numeric> TYPE numeric, "Numeric ((b, s), i, int8, p, decfloat16, decfloat34, f)
<p> TYPE p, "Packed number (generic length and number of decimal places)
@@ -461,8 +461,11 @@ ASSIGN s-structure TO <simple>.
ASSIGN s-xl1 TO <simple>.
"ASSIGN s-tab_ha TO <simple>.
ASSIGN s-oref TO <object>.
s-oref = NEW zcl_demo_abap_objects( ).
ASSIGN s-oref TO <object>.
"Accessing class attributes using casting
DATA(publ_str) = CAST zcl_demo_abap_objects( <object> )->public_string.
CAST zcl_demo_abap_objects( <object> )->another_string = `ABAP`.
```
<p align="right"><a href="#top">⬆️ back to top</a></p>

10
22_Misc_ABAP_Classes.md
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@@ -93,7 +93,7 @@ ENDTRY.
<td>
As an alternative to using the <code>IF_OO_ADT_CLASSRUN</code> interface for displaying output in the console, you can also use the <code>CL_DEMO_CLASSRUN</code> class, which offers more methods.
For more information, refer to <a href="https://blogs.sap.com/2023/10/24/abap-console-reloaded/">this blog</a>.
The following example makes use of <code>CL_DEMO_CLASSRUN</code> class for output purposes. A structure and an internal table are displayed in the console. Note the automatic dereferencing of the component. Plus, the <code>write_xml</code> method is shown, which displays XML data.
The following example makes use of the <code>CL_DEMO_CLASSRUN</code>. A structure and an internal table are displayed in the console. A structure component is a reference variable, which is automatically dereferenced. Plus, the <code>write_xml</code> method is shown, which displays XML data.
<br><br>
``` abap
@@ -604,7 +604,7 @@ DATA(str_no_blanks) = CONV string( chars ).
</td>
</tr>
<tr>
<td> <code>CL_ABAP_CONV_CODEPAGE</code><br><code>XCO_CP</code> </td>
<td> <code>CL_ABAP_CONV_CODEPAGE</code> </td>
<td>
For handling code pages, converting strings to the binary representation of different code pages and vice versa.
<br><br>
@@ -2181,7 +2181,7 @@ It only explores method calls and is intended to give a rough idea of the functi
<li>Third, a public API provided by GitHub is used to render markdown text to HTML. This is done by creating another client object. HTTP POST requests are sent, and the responses are retrieved. The responses should contain the code snippets converted to HTML in a string. The code snippets are added to HTML expandable sections.</li>
<li>Finally, the expandable sections containing the code snippets per cheat sheet are added to a simple HTML page. The code of the assembled HTML page is displayed in the ADT console.</li>
<li>For example and for demonstration purposes, if the HTML code is displayed in the ADT console, you can create a file named <em>ABAP_cheat_sheet_code.html</em> on your local machine. Open the file in an editor, copy and paste the entire ADT console content (it is recommended that you clear the ADT console before running the class to avoid copying and pasting unwanted output), and save the local file. Open the saved file in a web browser. You will now have several code snippets from the cheat sheets available offline.
In fact, the output (plain html with a lot of code) of this example is not a meaningful reference artifact and may not be of much use.
In fact, the output (plain html with a lot of code) of this example may not be a meaningful reference artifact.
Nevertheless, the example may give you an idea of how to use the ABAP classes, GET and POST requests, and so on (and you may also be interested in the various options for string processing as used in the example and described in the respective cheat sheet). Follow the links for more information. </li>
<li>Before using the GitHub APIs, make sure that you have consulted the following documentation: <a href="https://docs.github.com/en">GitHub Docs</a>, <a href="https://docs.github.com/en/enterprise-cloud@latest/rest/markdown/markdown?apiVersion=2022-11-28#render-a-markdown-document">Render a Markdown document</a>, <a href="https://docs.github.com/en/rest/using-the-rest-api/rate-limits-for-the-rest-api?apiVersion=2022-11-28">Rate limits for the REST API</a> </li>
</ul>
@@ -2245,7 +2245,7 @@ CLASS zcl_some_class IMPLEMENTATION.
"In the following loop, the raw markdown content is retrieved using an HTTP GET request, also
"by creating a client object and using a destination (another plain URL). The URL is constructed
"using the constant value plus the markdown file that was retreived before.
"using the constant value plus the markdown file that was retrieved before.
LOOP AT tab REFERENCE INTO DATA(cs).
url = url_gh && cs->file_name.
TRY.
@@ -2259,7 +2259,7 @@ CLASS zcl_some_class IMPLEMENTATION.
"snippet (indicated by the triple ```) is deleted.
"The replacements with dummy content in the loop are only done so that
"the POST request further down can work with the provided content
"(i.e. avoiding issues characters such as "; they are inserted later again).
"(i.e. avoiding issues with characters such as "; they are inserted later again).
LOOP AT snippets REFERENCE INTO DATA(line).
DATA(tabix) = sy-tabix.
FIND PCRE '^\s*```' IN line->*.

2
src/zcl_demo_abap_objects.clas.abap
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@@ -12,7 +12,7 @@
* classes to support the example.
* - Artifacts related to this example:
* - zdemo_abap_objects_interface: Separate global interface to demonstrate
* working with
* working with interfaces
* - zcl_demo_abap_objects_friend: Another global class used to demonstrate
* the concept of friendship
*