Interface and Message Types Introduction to Interface Development

In the example below, multiple receiver systems need to communicate with one sender system:

· In this example, the receiver SAP system does not support proxy generation. Instead, an IDoc and an RFC are used on the inbound side. To be able to access the names (and schema description) of these interfaces later during logical routing and mapping, you must import an XML description into the Integration Repository.

· However, you can generate an inbound proxy for the ABAP sender and the Java receiver. To do so, create two message interfaces in the Integration Repository.

Therefore, an outbound message interface can be connected to different receiver interfaces and the other way around. To model or document which interfaces belong together semantically, use an integration scenario.

For further examples, see Case Examples.

Interfaces and Message Types

When you define a message interface, you specify an output message type and an input message type:

· The output message type determines how the message to be sent is structured.

· The input message type determines how the message to be received is structured.

You reference one of the following object types from a message interface:

· Message types that have been created directly in the Integration Repository. These message types reference a data type that defines the message structure.

· Message schema from external definitions. External definitions are imported WSDL, XSD, or DTD documents. The proxy generation function can only process external definitions that fulfill certain prerequisites.

· The message schema of an imported IDoc.

· Message schemas of an imported RFC (request and, if applicable, response).

When you import RFCs or IDocs to the Integration Repository or import an external definition, the Integration Builder creates message objects in the Integration Repository that you can use in message interfaces. A message interface cannot reference different object types (for example, a message type and an RFC response).

Messages of imported interfaces or external definitions cannot be changed and are therefore not visible in the navigation tree of the Integration Builder.

XML Namespaces for Message Instances

An XML namespace is an additional identifier for the message instance. The XML namespace is either fixed or can be changed, depending on the type of your output or input message.

· (Fault) message types: You can choose any XML namespace in the Integration Builder.

· RFCs and IDocs: The XML namespace is defined in the Integration Builder. This corresponds to its fixed Repository namespace.

· External definitions: The XML namespace is defined in the imported document.

Identical messages must have the same XML namespace. Otherwise, you have to use a mapping to map an output message to an input message, merely because its namespace is different.