Invocation Channels - IBM BJ0NJML - Service And Asset Management Integration Manual

Integration Framework for Data Exchange

Invocation Channels

10
The Service Oriented Architecture (SOA) enables the use of external services to
process data from multiple sources. Invocation channels support a generic
service-oriented architecture capability by enabling the system to call an external
service synchronously. The invocation channel returns the response of the service
back to the caller for subsequent processing.
For example, you might want to use an external system to calculate the tax
amount for a product that you want to purchase. You can configure an invocation
channel to call the external tax service. The invocation channel then can save the
value of the external tax amount in the system database.
The initiation of an invocation channel is implemented by using an action class,
which then calls an invocation channel. You can implement an action by using the
following means:
A user interface control (within an application)
Workflow routing
Escalation
The system execution of an invocation channel is synchronous, and a response
can be returned from the external service to the caller.
The content of an invocation channel data structure is based on the associated
object structure. When the invocation channel processing starts, the integration
framework builds the XML message based on the object structure. The message
then moves through multiple processing layers before calling the external service.
The invocation channel can use the following processing layers:
User exit – Represents a Java class that you can use to filter data, transform
data, and implement business logic. You can use this class as part of an
installation-customization.
Data processing class – Represents a Java class that you can use to filter,
transform data, and implement business logic. Adapters for Oracle and
SAP provide processing classes to support integration to these products.
XSL map – Represents an XSLT style sheet that you can use to transform
data and perform mapping of the XML message to another format.
After the message goes through the processing layers, the integration framework
uses the configured endpoint to call the external service. The endpoint identifies
the protocol the system uses to send data, such as HTTP or a Web service. The
endpoint also identifies the property values that are specific to that endpoint,
such as URL, user name, and password.
When the message is delivered to the endpoint, the response of the service is
returned to the invocation channel. The response message can use similar
processing layers that are available on the response portion of the invocation
channel: user exit, process class, and XSL map. The response XML is mapped
back to the response object structure, which can be the same or different from the
object structure that initiated the message. The data mapped in the object
structure is returned to the caller of the channel for subsequent processing. The
Integration Guide