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returned, although it is no longer active and cannot be used to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.
- 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.
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
