Working with Process Interface

Using the process interface, a process definition of the provider model can be referenced in the consumer model. For the definition of the process interface, please refer to the chapter Glossary.

This chapter covers the following:

  1. Defining a Process Interface
  2. Implementing Process Interface
  3. Providing Process Interface
  4. Working with Referenced Process Definitions

Defining a Process Interface

To define a process interface:

Open the property page of the process definition and click on Process Interface

Properties
Figure: Process Definition Properties - Process Interface

You can define the process interface using the following options:

Process Interface
Figure: Process Interface

So there are three valid states concerning declared and implemented process interfaces:

Implementing Process Interface

A model that wants to provide an alternate implementation of its process definition should opt for Implements Process Interface option. It provides an implementation for a process interface defined in a provider model file.

When you select the Implement Process Interface option, the processes available for implementation are listed.

Implements Process Interface
Figure: Implements Process Interface

When you select the process to be implemented, its exposed parameters are listed under Process Interface.

Exposed Parameters
Figure: Exposed Parameters

Select the parameter. Only Data attribute is editable.

Parameter - Data Attribute
Figure: Parameter - Data Attribute

You can define more than one process interface implementation per process model.

If the defined Implements relationship is no longer valid due to changed parameter types, an inconsistency warning is displayed.

A warning is displayed in the Problems View in the following cases:

Note
When implementing a process interface in a different model, make sure to import data that is used in the process interface into the new model per reference. Creating data with the same Id is not sufficient and data values passed by the process interface will not be passed into the implementing process. Only data referenced from the model defining the process interface can be accessed correctly. No modeling validation is displayed to warn of this behavior.

Using Process Attachments over Process Interface Implementations

Process attachments do not work in a scenario where a subprocess is invoked that is an implementation of a process interface and was defined in a different model fragment. To avoid this problem, make sure that the model which implements the interface imports and overwrites his own process attachment data with the one of the provider model.

Providing Process Interface

This property defines the process interface. A model that wants to expose its process to other consumer model should choose this option. When a process interface property of a process definition is set to Provides Process Interface, it can be referenced from the consumer model.

Select the Provides Process Interface property and click on Add.

Provides Process Interface
Figure: Provides Process Interface

Specify following parameters to be exposed as IN/OUT values for referring model.

Process Interface Parameters
Figure: Process Interface Parameters

Process Interface Invocation

When the user defines a process interface, it is possible to specify how the interface is invokable:

For more information on REST and SOAP endpoints, please refer to the chapter Process Interface - External Invocation Mechanism of the Programming Guide.

To provide the remote invocation:

  1. Once you select the Provides Process Interface option from the properties of the process definition, select the Invocation tab
  2. Select the Invocation Type as SOAP or REST
  3. If you select SOAP, click Generate WSDL

    Process Interface Parameters
    Figure: Invocation Type - WSDL

    Process Interface Parameters
    Figure: Generated WSDL

    For more information, please refer to the WSDL/XSD mapping section.

  4. If you select REST, click Apply and OK.

WSDL/XSD Mapping

When Web service endpoint (SOAP) is selected a read only text area shows the WSDL code corresponding to the defined parameters. For the selected Process Interface a WSDL for WS invocation is created in document literal style (request/response message pair). The specified input and output data are mapped to XSD structures according to the following rules:

In case if at least one of the formal parameters does not satisfy the requirements for the external invocation, a validation error is displayed in the Problems view. Further, the corresponding WSDL code cannot be generated as the Generate WSDL button is disabled.

Working with Referenced Process Definitions

The referenced process definition becomes the subprocess in the referencing model. For more information, please refer External Model Fragments section of the External Model Resources from the Developers Handbook. To define the subprocess implementation for referenced process definition:

  1. Open the Property page of the subprocess activity in the referencing process definition.
  2. Click on Subprocess

    Properties of Referenced Process Definition
    Figure: Referenced Process - Subprocess

  3. Select the Execution Type and subprocess implementation


    Figure: Subprocess Implementation

    If the selected subprocess is a referenced process from a provider model then the following execution types are available:

    By default, Synchronous / Separate Data is selected.

    Note that in these cases invocation at runtime is always done via the process interface.
    If the selected subprocess is a process from the same model then the subprocess will be invoked directly at runtime as no process interface exists. For more information on execution types of such subprocess, please refer to chapter Configuring Subprocess Activities .

  4. Note that if the Displays Imported Model Elements as Groups check box is selected, the subprocess list displays references for the referenced process definitions. Selecting the check box also groups local and referenced elements.


    Figure: Display Imported Model Element as Groups

  5. To create data mappings related to the process interface parameters, you can use processInterface context. Process Interface context in data mapping will only be available in the process which has references to other model. For example, the referenced subprocess of the consumer model will have the process interface context.


    Figure: Process Interface Context

  6. To define the process interface context:

Dynamic Binding of Subprocess Implementation

Dynamic binding enables you to choose the implementation model at runtime. To enable the dynamic binding, you can mark the subprocess activity that invokes process interface, to be resolved at runtime.

Open the properties of the referenced process definition and click on Runtime Binding.


Figure: Subprocess Activity

Select the option Subprocess is resolved at runtime.

In the Data drop-down list, it is mandatory to provide the target model or implementation model ID with type string. This model ID is used to invoke the process definition that implements the selected process interface.


Figure: Subprocess Activity - Runtime Binding

Note that the ID of the implementing process definition is fetched from the declared implements relationship to the process interface.