Message Interface

Use

You use a message interface to describe a platform-independent or programming-language-independent interface, which you want to use to exchange messages between application components using SAP Exchange Infrastructure. Depending on the communication parameters defined for a message interface, it can either have the task of sending a request (outbound) or receiving a request (inbound). Assigning an outbound interface to an inbound interface enables multiple communication parties to exchange messages with each other (see also: Communication Parties (Case Examples)). The following connections are possible for message interfaces:

· A message interface with another message interface

· A message interface with an imported interface

· A message interface with an interface configured by an adapter

By using proxy generation, message interfaces enable ABAP and Java applications to be interconnected.

Prerequisites

From message interfaces, you reference message types, fault message types, messages from external definitions, or RFC or IDoc messages. It is possible to save message interfaces without referencing these objects, but their definition would then be incomplete.

For more information, see the Prerequisites section in Introduction to Interface Development.

Features

Communication Parameters

When you create a message interface you define the communication parameters by using the attributes Mode and Category. You can create the following types of message interfaces:

Category	Mode		Use
	Synchronous	Asynchronous
Inbound	Synchronous inbound message interface	Asynchronous inbound message interface	Proxy communication
Outbound	Synchronous outbound message interface	Asynchronous outbound message interface
Abstract	Synchronous abstract message interface	Asynchronous abstract message interface	Defines the process signature

Depending on the attributes you define for the message interface, you either need to reference one or two message types in Message Types. Therefore, the input message type defines the expected message, while the output message type defines the message sent.

If you want to handle application-specific errors or persist them in monitoring, assign the corresponding fault message types to the message interface as well.

Fault messages transfer errors on the receiver side to the sender or to monitoring. Therefore, you cannot define fault messages for asynchronous abstract message interfaces or asynchronous outbound message interfaces.

Enhanced Functions

Once you have created a message interface you can do the following:

· Assign context objects for request message fields to use later instead of XPath expressions in an integration process or in logical routing.

· Generate a proxy for use at runtime by using ABAP proxy generation or Java proxy generation.

· Export the interface description as a WSDL document (see: Exporting XSD and WSDL Documents).

Activities

...

1. Create a message interface on the design maintenance screen of the Integration Builder (see: Creating an Object).

2. Enter a description for your message interface.

3. Define the communication parameters in the Attributes frame.

4. In Message Types, reference the required input or output message types, or both. For a list of the possible object types, see Interface and Message Types.

5. If the interface is not an asynchronous outbound message interface or an abstract message interface, you have the option of referencing fault message types in the lower table in the Message Types frame. To do so, use the following functions:

Edit References to Fault Messages

Function	Use
	Adds an additional line to the table. Enter the fault message type in the inserted line either manually or by using the input help (see below).
	Located at the end of a table line. Calls the input help to select a fault message type.
	Changes the sequence of the fault message types.
	Deletes a reference to a fault message type.

6. You have the option of assigning context objects to fields by using the input help. This is possible for scalar type attributes and elements.

7. Save your changes.