https://github.com/furkancosgun/either-for-abap
`EITHER FOR ABAP` is a design pattern used in ABAP programming to standardize the management of results and errors. This pattern helps in handling operations that can either succeed with a result or fail with an error, which can be of various types.
https://github.com/furkancosgun/either-for-abap
abap abapgit either result
Last synced: 14 days ago
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`EITHER FOR ABAP` is a design pattern used in ABAP programming to standardize the management of results and errors. This pattern helps in handling operations that can either succeed with a result or fail with an error, which can be of various types.
- Host: GitHub
- URL: https://github.com/furkancosgun/either-for-abap
- Owner: furkancosgun
- License: mit
- Created: 2024-08-28T08:22:52.000Z (8 months ago)
- Default Branch: main
- Last Pushed: 2024-08-28T08:49:56.000Z (8 months ago)
- Last Synced: 2025-04-07T02:47:26.941Z (14 days ago)
- Topics: abap, abapgit, either, result
- Language: ABAP
- Homepage:
- Size: 16.6 KB
- Stars: 6
- Watchers: 1
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: LICENSE
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README
# EITHER FOR ABAP
`EITHER FOR ABAP` is a design pattern used in ABAP programming to standardize the management of results and errors. This pattern helps in handling operations that can either succeed with a result or fail with an error, which can be of various types.
## License
This project is licensed under the [MIT License](LICENSE). See the LICENSE file for details.
## Contents
- [Overview](#overview)
- [Pattern Definition](#pattern-definition)
- [Method Examples](#method-examples)
- [Usage Example](#usage-example)
### Overview
The `Either` pattern represents the outcome of an operation with two possible results: a successful result (`right`) or an error message (`left`). This pattern enhances code readability and error handling by encapsulating results and errors in a consistent manner.
### Pattern Definition
The `Either` pattern provides a structure that can carry two types of values:
1. **Left**: Represents error messages or failure results.
2. **Right**: Represents successful results.
Below is a simplified definition of the `zcl_either` class:
```abap
CLASS zcl_either DEFINITION.
PUBLIC SECTION.
" Creates an instance based on a condition
CLASS-METHODS cond
IMPORTING
!condition TYPE boolean " Condition to determine result
!left_value TYPE any " Value for the left (error)
!right_value TYPE any " Value for the right (success)
RETURNING
VALUE(ro_either) TYPE REF TO zcl_either
RAISING
zcx_either_invalid_type. " Exception for invalid types
" Creates an instance with a left value (error)
CLASS-METHODS left
IMPORTING
!value TYPE any " Error result
RETURNING
VALUE(ro_either) TYPE REF TO zcl_either
RAISING
zcx_either_invalid_type. " Exception for invalid types
" Creates an instance with a right value (success)
CLASS-METHODS right
IMPORTING
!value TYPE any " Success result
RETURNING
VALUE(ro_either) TYPE REF TO zcl_either
RAISING
zcx_either_invalid_type. " Exception for invalid types
" Checks if the instance is a left value
METHODS is_left
RETURNING
VALUE(r_boolean) TYPE boolean. " Returns TRUE if left value
" Checks if the instance is a right value
METHODS is_right
RETURNING
VALUE(r_boolean) TYPE boolean. " Returns TRUE if right value
" Retrieves the left value
METHODS get_left
EXPORTING
VALUE(value) TYPE any " Retrieves left value
RAISING
zcx_either_invalid_access. " Exception for invalid access
" Retrieves the right value
METHODS get_right
EXPORTING
VALUE(value) TYPE any " Retrieves right value
RAISING
zcx_either_invalid_access. " Exception for invalid access
ENDCLASS.
```
### Method Examples
Here are some examples of how the `zcl_either` class can be used:
1. **`divide_numbers` Method**: Divides two numbers and returns the result or an error message if division by zero is attempted.
```abap
METHOD divide_numbers.
IF iv_denominator = 0.
ro_result = zcl_either=>left( 'Division by zero error' ).
ELSE.
DATA(lv_result) = iv_numerator / iv_denominator.
ro_result = zcl_either=>right( lv_result ).
ENDIF.
ENDMETHOD.
```
2. **`fetch_data` Method**: Retrieves data based on an ID and returns the data or an error message if the ID is invalid.
```abap
METHOD fetch_data.
IF iv_id < 1.
ro_result = zcl_either=>left( 'Invalid ID' ).
ELSE.
DATA(lv_data) = 'Fetched Data'.
ro_result = zcl_either=>right( lv_data ).
ENDIF.
ENDMETHOD.
```
3. **`process_order` Method**: Processes an order based on the order ID and returns a success or error message.
```abap
METHOD process_order.
CASE iv_order_id.
WHEN 1.
ro_result = zcl_either=>right( 'Order processed successfully' ).
WHEN 2.
ro_result = zcl_either=>left( 'Order already processed' ).
WHEN OTHERS.
ro_result = zcl_either=>left( 'Order not found' ).
ENDCASE.
ENDMETHOD.
```
4. **`complex_operation` Method**: Performs a complex operation and handles errors based on the input.
```abap
METHOD complex_operation.
DATA: lv_intermediate TYPE i.
IF iv_input < 0.
ro_result = zcl_either=>left( 'Negative input not allowed' ).
ELSEIF iv_input = 0.
ro_result = zcl_either=>left( 'Zero input not valid' ).
ELSE.
lv_intermediate = iv_input * 2.
ro_result = zcl_either=>right( lv_intermediate ).
ENDIF.
ENDMETHOD.
```
### Usage Example
Here’s an example of how to use the `zcl_either` class in practice:
```abap
START-OF-SELECTION.
DATA: lo_example TYPE REF TO zcl_either_example,
lo_result TYPE REF TO zcl_either,
lv_result TYPE i,
lv_error TYPE string.
" Create an instance of the class
lo_example = NEW zcl_either_example( ).
" Test Example-1: divide_numbers
lo_result = lo_example->divide_numbers(
iv_numerator = 10
iv_denominator = 0
).
IF lo_result->is_left( ).
" Retrieve and display the error message
lo_result->get_left( IMPORTING value = lv_error ).
WRITE: / 'Error in divide_numbers:', lv_error.
ELSE.
" Retrieve and display the result
lo_result->get_right( IMPORTING value = lv_result ).
WRITE: / 'Result of divide_numbers:', lv_result.
ENDIF.
" Test Example-2: fetch_data
lo_result = lo_example->fetch_data(
iv_id = 0
).
IF lo_result->is_left( ).
" Retrieve and display the error message
lo_result->get_left( IMPORTING value = lv_error ).
WRITE: / 'Error in fetch_data:', lv_error.
ELSE.
" Retrieve and display the data
lo_result->get_right( IMPORTING value = lv_result ).
WRITE: / 'Data from fetch_data:', lv_result.
ENDIF.
" Test Example-3: process_order
lo_result = lo_example->process_order(
iv_order_id = 2
).
IF lo_result->is_left( ).
" Retrieve and display the error message
lo_result->get_left( IMPORTING value = lv_error ).
WRITE: / 'Error in process_order:', lv_error.
ELSE.
" Retrieve and display the success message
lo_result->get_right( IMPORTING value = lv_error ).
WRITE: / 'Success message from process_order:', lv_error.
ENDIF.
" Test Example-4: complex_operation
lo_result = lo_example->complex_operation(
iv_input = 5
).
IF lo_result->is_left( ).
" Retrieve and display the error message
lo_result->get_left( IMPORTING value = lv_error ).
WRITE: / 'Error in complex_operation:', lv_error.
ELSE.
" Retrieve and display the result
lo_result->get_right( IMPORTING value = lv_result ).
WRITE: / 'Result of complex_operation:', lv_result.
ENDIF.
```
Feel free to adjust these suggestions based on your specific needs or the context of your project!