com.whitestein.lsps.engine

Interface ExecutableTask

All Known Subinterfaces:

AsynchronousExecutionTask

All Known Implementing Classes:

AbstractAsynchronousExecutionTask, AddPersonToRole, AddProcessLog, Assign, BaseTodoTask, ConvertToXmlTask, CreateModelInstance, CustomUIUserTask, CustomUIWithContextUserTask, DeactivateGoal, DeleteModelInstanceLogs, DeleteSharedRecords, Execute, HttpClientTask, HumanInteractionTask, Lock, NoOperationTask, ParseXmlTask, ReactivateGoal, RemoveBinaryData, RemovePersonFromRole, RepeatGoals, RestRequestWaitpointTask, RestResponseTask, RunSQLTask, SendEmail, TaskProxy, TerminateModelInstance, TestRollbackExceptionTask, Unlock, UserTask, WsRequestWaitPointTask, WsResponseTask, WsSoapCall

public interface ExecutableTask

Basic interface for implementation of custom tasks.

Parameters of the task can be get using the provided task execution context, using the method TaskContext.getParameter(String) . Task execution context provides also access to process variables, a namespace, a parent context etc.

The following table describes the mapping between the model types and Java types:

GO-BPMN Model Type	Java Type
Boolean	java.lang.Boolean
Integer	com.whitestein.lsps.lang.Decimal
Decimal	com.whitestein.lsps.lang.Decimal
String	java.lang.String
Date	java.util.Date
Object	java.lang.Object
List<T>	com.whitestein.lsps.lang.exec.ListHolder
Set<T>	com.whitestein.lsps.lang.exec.SetHolder
Map<K,V>	com.whitestein.lsps.lang.exec.MapHolder
Reference<T>	com.whitestein.lsps.lang.exec.ReferenceHolder
Closure	com.whitestein.lsps.lang.exec.ClosureHolder
record types	com.whitestein.lsps.lang.exec.RecordHolder

Task execution starts by the invoking the method start. The initial code should be placed there. If the method returns FINISHED, the method terminate is called and the task execution is finished. If the method returns WAITING_FOR_INPUT , the method processInput will be called when a new input comes into the model instance. The method processInput is called repeatedly with each new input until it returns FINISHED. Finally, the method terminate is called the the task execution is finished.

The method terminate is called also when the task is terminated abnormally, e.g. by a timeout intermediate event attached on the task.

The methods start and processInput must be implemented in such a way that the thread is not blocked.

The task methods may throw ErrorException. It is equivalent to an error modeled in the BPMN diagrams. Such an error can be caught by an error intermediate event attached on the task.

If a task is implemented as a stateless session bean, it can use interceptor RuntimeExceptionCatcherInterceptor to catch all exceptions thrown from it's business methods and convert them to ErrorException.

Author:

bhl, rba

Nested Class Summary

Nested Classes

Modifier and Type	Interface and Description
static class	ExecutableTask.Result A result controlling the task execution.

Method Summary

Modifier and Type	Method and Description
ExecutableTask.Result	processInput(TaskContext context, Object input) The method for processing the model instance input.
ExecutableTask.Result	start(TaskContext context) An initial method that is called when the task execution starts.
void	terminate(TaskContext context, TerminationReason reason) Called when this task is to be terminated.

Method Detail

start

ExecutableTask.Result start(TaskContext context)
                     throws ErrorException

An initial method that is called when the task execution starts.

Parameters:

context -

Returns:

result of execution, must not be null

Throws:

ErrorException - the BPMN error

processInput

ExecutableTask.Result processInput(TaskContext context,
                                   Object input)
                            throws ErrorException

The method for processing the model instance input.

This method is invoked when a previous call to either start method or processInput method returned WAITING_FOR_INPUT and a new input is to be process by the model instance.

Parameters:

context -

input -

Returns:

result of execution, must not be null

Throws:

ErrorException - the BPMN error

terminate

void terminate(TaskContext context,
               TerminationReason reason)
        throws ErrorException

Called when this task is to be terminated. This method is called also in case of normal task completion.

Parameters:

context -

reason -

Throws:

ErrorException - the BPMN error

See Also:

ErrorException