Top-level business object and content
configuration
Metadata is embedded along with business object data in
the WfMessage structure of WebSphere MQ Workflow. This structure
is the basis for all requests and responses between the connector
and WebSphere MQ Workflow using the XML message API. The structure
of all messages is shown in Figure 7:
Figure 7. WebSphere MQ Workflow message structure
Commands and return values in the XML API are encompassed by "templates." These
templates provide the structures necessary to specify entire commands
to WebSphere MQ Workflow as well as to contain the results. The
type of template changes depending on the action requested and,
in most cases, the business content is contained in a child element
of the template. Identifying the business content requires that
the connector recognize each template specifically. As the names
of the templates differ, so do the names of the child elements.
The connector can process three templates
and their associated response structures:
- ProcessTemplateExecute
- Sent by the connector to the WebSphere MQ Workflow server
to execute a process either synchronously or asynchronously. If
the process is asynchronously executed, no response is issued by WebSphere
MQ Workflow. If the process is executed synchronously, a response
is returned only after the workflow process has completed. A business
object representing the workflow input data structure is contained
in child element ProcInstInputData.
- ProcessTemplateExecuteResponse
- Sent by WebSphere MQ Workflow in response to a synchronous request
issued by the connector. The business object that results from the
workflow process is contained in child element ProcInstOutputData.
A process instance identifier (PID) is returned, although it is
no longer active and cannot be used to control the workflow further.
- ProcessTemplateCreateAndStartInstance
- Sent by the connector to the WebSphere MQ Workflow server
to execute a process asynchronously. Unlike in the ProcessTemplateExecute
template, a response is issued immediately to the connector containing
the active PID (instead of a business object). This PID can later
be used to control the workflow process. A business object representing
the data structure destined for the workflow is contained in child
element ProcInstInputData.
- ProcessTemplateCreateAndStartInstanceResponse
- Sent by WebSphere MQ Workflow in response to a request sent
by the connector. A PID is returned without a business object (because
the workflow is assumed to be executing asynchronously).
- ActivityImplInvoke
- Sent by WebSphere MQ Workflow to the connector to request
that business content be posted to InterChange Server. The business
object is contained by child element ProgramInputData. WebSphere
MQ Workflow may include an additional child element ProgramOutputDataDefault
that contains default values for the business content returned to
the workflow for synchronous requests.
Note:
For UPES Version 3.2.2 and higher: A message is
sent to invoke an activity implementation. A response is required
in the case of a synchronous invocation.
- ActivityImplInvokeResponse
- Returned by the connector to WebSphere MQ Workflow to complete synchronous
requests processed during event polling. The business object returned
by the collaboration is added to child element ProgramOutputData.
When an error occurs, MQ Workflow replies with an "ActivityImplInvokeResponse"
into the error queue. The workflow server processes the message
and takes the corresponding action.
Depending on the structure of the processed template, the connector
must either retrieve or add business content from one of the following
XML child elements:
- ProcInstInputData
- ProcInstOutputData
- ProgramInputData
- ProgramOutputData
