How to Create Shared Memory Object Class in ABAP
Table of Contents
Create AREA ROOT Class for Shared Memroy Object Area
The first step is to create an Area Rool class. ( let’s say ZCL_ROOT)
Go to SAP Transaction SE24 and create a new class.
Make sure you checked “Shared Memory Enabled” under Class/Interface Propertiess Tab as following:
Create 2 Instance Attributes
The next step is to create, for example, 2 Instance Attributes within this class.
The Visibility has to be set to Private .
Create SET_DATA & GET_DATA Method
Both of these methods SET_DATA and GET_DATA with handle Shared Memory Object Write and Read operation. We will come back to these methods’ implementation later.
Check also How to use EXPORT or IMPORT data to / from ABAP Memory ID
Create SAP Shared Memory Area ( SHMA )
Launch the Transaction SHMA and create a new Area Name. (ZCL_MEM_AREA for sample)
Fill a short description for the Memory Shared Area. In the Root Class, put the class you have created above ( ZCL_ROOT ).
When saving, SAP will generate an area Class with the same name as the Area Name ( ZCL_MEM_AREA ). The new generated Area Class will contains all the methods needed to read, write and update the Shared Memory Object.
Shared Memory Object Area Class’s Methods
| Method | Visibility | Description |
|---|---|---|
| ATTACH_FOR_READ | Public | Request a Read Lock |
| ATTACH_FOR_UPDATE | Public | Request a Change Lock |
| ATTACH_FOR_WRITE | Public | Request a Write Lock |
| BUILD | Static | Direct Call of Area Constructor |
| SET_ROOT | Instanciate | Sets Root Objects |
SET_DATA and GET_DATA Implementation
Once you have created the area root class, the area class and generated the area class, you can implement the ABAP code for the SET_DATA and GET_DATA in order to read/Write the Shard Memory Object.
Write data in Shared Memory Area (SET_DATA)
In order to save data into an instance of Shared Memory Object, you can set the data as following :
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 | DATA: my_handle TYPE REF TO zcl_mem_area. DATA: my_root TYPE REF TO zcl_area_root. TRY . CALL METHOD zcl_mem_area=>attach_for_write EXPORTING inst_name = cl_shm_area=>default_instance attach_mode = cl_shm_area=>attach_mode_default wait_time = 0 RECEIVING handle = my_handle. CREATE OBJECT my_root AREA HANDLE my_handle. CALL METHOD my_root->set_data EXPORTING name = 'name_test' value = 'value_test'. CALL METHOD my_handle->detach_commit. CATCH cx_shm_exclusive_lock_active . CATCH cx_shm_version_limit_exceeded . CATCH cx_shm_change_lock_active . CATCH cx_shm_parameter_error . CATCH cx_shm_pending_lock_removed . ENDTRY. |
Read data in Shared Memory Area (GET_DATA)
here an example how to use the GET_DATA in order to read an instance of Shared Memory Object:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 | DATA: my_handle TYPE REF TO zcl_mem_area. DATA: my_root TYPE REF TO zcl_area_root. TRY . CALL METHOD zcl_mem_area=>attach_for_read EXPORTING inst_name = zcl_mem_area=>attach_for_write RECEIVING handle = my_handle. CREATE OBJECT my_root AREA HANDLE my_handle. CALL METHOD my_root->get_data IMPORTING name = lv_name value = lv_value. CALL METHOD my_handle->detach_commit. CATCH cx_shm_inconsistent . CATCH cx_shm_no_active_version . CATCH cx_shm_read_lock_active . CATCH cx_shm_exclusive_lock_active . CATCH cx_shm_parameter_error . CATCH cx_shm_change_lock_active . ENDTRY. |
Note that NAME and VALUE are the attribute of the Area Root Class.
List of Area Root Class Exception
Here the list of the main exception Class for Area Root:
