Persistent And Runtime Object References in Workflow

Posted on Mar. 03, 2009 06:11 AM, Kuala Lumpur, Malaysia

Have you heard about persistent and runtime references? What do they mean? Why do SAP requires both persistent and runtime reference? How do they affect the way we program the workflow? If you have these questions in your mind then you should continue reading this blog.

What is persistent and runtime object references?

In workflow runtime, BOR objects are represented by SWC_OBJECT variables. However, in order to save object references in the database and transport them beyond session limits, persistent object reference variables of the ABAP type SWOTOBJID are used.

Why do SAP requires both persistent and runtime reference?

The workflow system stores object references in the container. These object references must be saved in the database whenever there is a context change (switch from one step to the next). This mechanism ensures the workflow can be restarted in case of server down or system crash using transaction SWPC.

For this purpose, the workflow system converts the object references in the container from the runtime representation (blue areas) to the persistent representation (green areas) and back again, as required.

How do they affect the way we program the workflow?

One example is when you want to start the workflow directly from the function module, not through event. Since the workflow can only be started with the persistent object reference, then we need to convert the containers passed to the workflow into persistent object references, using macro SWC_CONTAINER_TO_PERSISTENT<CONTAINER>.

1. When calling the workflow from API

*create and populate runtime object reference

SWC_CREATE_OBJECT OBJECT 'Z00MARA' OBJKEY.

SWC_SET_ELEMENT WI_CONTAINER 'MaterialMaster' OBJECT.

*Convert references in container from runtime handle to persistent object reference

SWC_CONTAINER_TO_PERSISTENT WI_CONTAINER.

*start the workflow via the function API

CALLFUNCTION 'SWW_WI_START_SIMPLE'

EXPORTING

* CREATOR = ' '

* PRIORITY = NO_PRIO

TASK = TASK

* CALLED_IN_BACKGROUND = ' '

* DEADLINE_DATA = ' '

IMPORTING

WI_ID = WI_ID

* wi_header =

* RETURN =

* WI_RESULT =

TABLES

AGENTS = AGENTS " notneeded here

* DEADLINE_AGENTS =

* DESIRED_END_AGENTS =

* LATEST_START_AGENTS =

* EXCLUDED_AGENTS =

* NOTIFICATION_AGENTS =

* SECONDARY_METHODS =

WI_CONTAINER = WI_CONTAINER

EXCEPTIONS

ID_NOT_CREATED = 1

READ_FAILED = 2

IMMEDIATE_START_NOT_POSSIBLE = 3

EXECUTION_FAILED = 4

INVALID_STATUS = 5

OTHERS = 6.

Other example is when you want to use alternative binding, or programmed binding. Since the container is stored persistently when the workflow manager calls the programmed binding, then it's necessary to convert the container values to runtime first using SWC_CONTAINER_TO_RUNTIME <CONTAINER> after which we need to reconvert them back to persistent object references using SWC_CONTAINER_TO_PERSISTENT<CONTAINER> as discussed in the first example.

2. When using programmed binding

function z00_bind_wf_to_display_step.

*"----------------------------------------------------------------------

*"*"Localinterface:

*" IMPORTING

*" VALUE(DATAFLOW) LIKE SWABINDEF-DATAFLOW

*" TABLES

*" CALLED_CONTAINER STRUCTURE SWCONT

*" CALLING_CONTAINER STRUCTURE SWCONT

*"----------------------------------------------------------------------

data: mat_object type SWC_object.

data: mat_view like t132t-statm.

if dataflow eq 'E'.

" only consider export dataflow from wf to wi container

" read data from workflow (= calling) container

SWC_CONTAINER_TO_RUNTIME CALLING_CONTAINER.

SWC_CONTAINER_TO_RUNTIME CALLED_CONTAINER.

SWC_GET_ELEMENT_CALLING_CONTAINER 'MaterialMaster' mat_object.

SWC_GET_ELEMENT_CALLING_CONTAINER 'MaterialView' mat_view.

" write data to work item (= called) container

SWC_SET_ELEMENT_CALLED_CONTAINER wi_leading_object mat_object.

SWC_SET_ELEMENT_CALLED_CONTAINER 'MaterialView' mat_view.

SWC_CONTAINER_TO_PERSISTENT CALLING_CONTAINER.

SWC_CONTAINER_TO_PERSISTENT CALLED_CONTAINER.

endif.

endfunction.

Conclusion

1. Event manager/program always uses runtime object reference.

2. Workflow manager/program always works with persistent object reference.

3. Work item or BOR manager/program always works with runtime object reference.

4. Use macro SWC_CONTAINER_TO_PERSISTENT<CONTAINER> to convert runtime into persistent object reference

5. Use macro SWC_CONTAINER_TO_RUNTIME <CONTAINER> to convert persistent into runtime object reference

Ruslim Chang Senior Process Integrator

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Hope the understanding of persistent and runtime objects helps you to program your workflow better.Comment on this weblog

• Few points on this
• 2009-03-05 05:00:02 DevRaj Singh Business Card [Reply]
• Hi Chang,
  • First of all thanks for the nice blog.
  • But I still have few points to mention on this. Like as you have mentioned that
  • *Convert references in container from runtime handle to persistent object reference
  • SWC_CONTAINER_TO_PERSISTENT WI_CONTAINER.
  • In first example.....
  • But if we do not go with this step then also we can call workflow without event with a particular instance.
  • 1 - When I have tried to use WC_CONTAINER_TO_PERSISTENT micro (<CNTN01> already included) then report was giving syntax error.
  • 2 - Then I have simulated FORMABSENCE scenario on this but i have done it with out converting reference in container to persistent.
  • 3 - Where it stores the persistent objects in SAP if convert object reference to persistent.
  • Please provide your valuable input on the following points.
  • Regards
  • Devraj Singh
    • Few points on this
    • 2009-03-05 17:21:18 Ruslim Chang Business Card [Reply]
    • Appreciate your comment.
      • 1. Could you please check your system in the include <CNTN01> whether the macro exist? If it exists, then it could be due to container type difference. Please try to define your container like this: WI_CONTAINER LIKE SWCONT OCCURS 0 WITH HEADER LINE.
      • 2. What is the API you use to trigger the workflow?
      • 3. By default if you are using WAS 6.2 and above, the container will be stored as XML. The setting is on your workflow basic data -> Version Dependent -> Control -> Persistence Profile. However for downward compatibility, SAP also stores container values in SWW_CONT and SWW_CONTOB.
        • Few points on this
        • 2009-03-05 22:50:16 DevRaj Singh Business Card [Reply]
        • Hi Chang,
          • Thanks For replying..
          • 1 - I am OK with the first point which you made.
          • 2 - I am using SWW_WI_START_SIMPLE for triggering and its working fine without changing the container to persistent, but if I do then also it's working fine. The differences I have observed in runtime are as following,
          • If I will not convert container to persistent then the value which is exist into the container is the value of handler, which is generating while the execution of SWC_CREATE_OBJECT OBJECT 'FORMABSENC' Number.
          • But if I convert then it's replaced to concatenation of (Logical System Name, Object Type, and Object Key).
          • But in both the cases it is triggering WF so how does it have making a difference?
          • 3- Can we check XML form of container, I mean XML persistence?
          • Regards
          • Devraj Singh
          • Patni Computer systems
            • Few points on this
            • 2009-03-06 20:26:44 Ruslim Chang Business Card [Reply]
            • Hi,
              • 2. Yes, you are right too. It looks like FM SWW_WI_START, the function module called inside FM SWW_WI_START_SIMPLE might have been enhanced by SAP to to handle this scenario. However, for programmed binding, it will not work without conversion.
              • 3. You can read the XML persistence using FM SAP_WAPI_READ_CONTAINER where one of the exporting value is XML persistent container.
                • Thanks Chang
                • 2009-03-08 22:58:55 DevRaj Singh Business Card [Reply]
                • Hi Chang,
                  • For nice blog and clearing my points.Hope to see some more blog like this in future.
                  • Regards
                  • Devraj Singh

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