Implementing Exception Handling

Use

In a Guided Procedures (GP) process you can create actions that handle exceptions raised by callable object execution. Additionally, you can choose a strategy to repeat or skip the activity that caused the exception.

Prerequisites

• You have instantiated the IGPDesigntimeUpdateManager .

  See Instantiating the Design Time Manager .

• You have familiarized yourself with the implementation of development objects with the GP design time API.

  See Creating GP Development Objects .

• You have created a block.

  See Creating Blocks .

Procedure

1. Create a callable object and define an exception for it.

importcom.sap.caf.eu.gp.co.api.IGPCallableObject;

importcom.sap.caf.eu.gp.process.dt.api.IGPDesigntimeUpdateManager;

importcom.sap.caf.eu.gp.co.api.IGPPhysicalCallableObject;

// create a callable object

IGPCallableObjectco = manager.createCallableObject(

            coType,

            locale,

            coTitle,

            coDescription,

            cat.getID()

            );

// retrieve the physical callable object

IGPPhysicalCallableObject pco= co.resolvePhysicalCallableObject();

// define one process exception "e"

pco.addProcessException("e","E");

// save and activate the object

manager.save(co);

manager.activate(co);

For more information on how to create callable objects, see Creating Callable Objects .

1. Insert the callable object into an action and add the action to the block structure.

// set execute callable object co to action a_2

a_2.setExecuteCallableObject(co);

manager.save(a_2);

// add a_2 to the block structure

b.getModifiableStructure().addItem(a_2);

For more information on how to create actions, see Creating Actions .

1. Create an exception handling action.

   During process execution, the callable object that you created may raise a process exception. You need a mechanism to handle this exception. For this purpose you create an additional action, which determines the processing strategy and informs the user about possible problems.

   This action is executed whenever such an exception is raised. Its implementation is standard:

//define action for the exception handler

IGPModifiableActionae = manager.createAction(

                                      locale,

                                      "ae",

                                      "ae description",

                                      cat.getID()

                                      );

// save and activate the action

manager.save(ae);

manager.activate(ae);

1. Assign the exception handling action to the block structure item corresponding to the action with the process exception.

importcom.sap.caf.eu.gp.process.api.IGPModifiableBlockStructureItem;

importcom.sap.caf.eu.gp.process.api.GPExceptionHandlingStrategy;

// retrieve block structure item of action a_2

IGPModifiableBlockStructureItemia_2 = b.getModifiableStructure().getModifiableItem(1);

// create exception handler on ia_2

ia_2.setExceptionHandler("e",GPExceptionHandlingStrategy.STRATEGY_CONTINUE, ae);

The example above also specifies the processing strategy after the exception handling action has been executed. The strategies you can choose from are:

• STRATEGY_CONTINUE

  - process flow continues with the next item in the structure

• STRATEGY_REPEAT

  - process flow repeats the item that caused the exception