IBM BPM, V8.0.1, All platforms > Get started with IBM BPM > Key concepts > BPEL processes and human tasks > Human tasks overview > Scenarios for invoking tasks
Factors affecting the behavior of stand-alone invocation tasks and their service components
You can use a stand-alone invocation task to run an SCA service component that is associated with the SCA component of the task. The association of the invocation task and service component is modeled at an SCA level by wiring the reference of the task component to the interface of the associated service component. A number of factors affect the behavior of the invocation task and its associated service component.
- WSDL operation type
- SCA references and SCA interfaces are associated with a WSDL port type containing one or more operations. Each operation can be a one-way or a request-response operation:
- A one-way operation implies a service execution the completion of which is not made known to the invoking task. The task service execution ends with the successful invocation of the associated service.
- A request-response operation implies a service execution the completion of which is made known to the invoking task. The task execution ends when the result of the service execution is made available to the invoking task.
- API invocation method
- The Human Task Manager API supports the following interaction styles for tasks:
- Synchronous invocation of the task and its associated service using the callTask method
- Asynchronous invocation of the task and its associated service using the startTask method
- Execution duration of the service component
- The value that you set for the execution duration must account for the load that you expect to be caused by other workloads on your system. The execution duration also has to be considered in relation to the transaction time-out value set for the server that hosts Business Process Choreographer. Compare these values before you decide to make a service component with a request-response interface available for synchronous invocation. In such cases, the execution time of your service component must be below the transaction time-out value that is set for the server.
- SCA qualifier settings
- Only certain combinations of SCA qualifiers are allowed for the task component reference and service component interface.
Related concepts:
Scenarios for invoking tasks