¶ Working with Abstract and Concrete Interfaces in SAP PI/PO
Subject: SAP-PI-PO (Process Integration / Process Orchestration) | Field: SAP Technology
In SAP Process Integration (PI) and Process Orchestration (PO), interfaces form the backbone of system communication. Understanding the distinction between Abstract and Concrete Interfaces is essential for designing robust, reusable, and maintainable integration scenarios. This article explains the concepts, roles, and best practices for working with Abstract and Concrete Interfaces in SAP PI/PO.
An interface in SAP PI/PO defines the structure and communication contract for exchanging messages between sender and receiver systems. It specifies message types, operations, communication protocols, and message processing rules.
Interfaces in SAP PI/PO are categorized into:
- Abstract Interfaces
- Concrete Interfaces
Abstract Interfaces define the business-level message structure and semantics without specifying technical details related to the communication protocol or system.
Key characteristics:
- Represent logical or design-time interfaces.
- Describe the message structure (e.g., data types, elements) and operations (e.g., synchronous/asynchronous).
- Do not contain information about the sender or receiver system or the communication protocol.
- Designed and stored in the Enterprise Services Repository (ESR).
- Promote reusability by allowing multiple communication scenarios to use the same abstract interface.
- Serve as a blueprint for message transformation and validation.
Concrete Interfaces extend Abstract Interfaces by adding technical details to enable message transmission.
Key characteristics:
- Represent runtime or configuration-level interfaces.
- Specify sender or receiver system details (e.g., business system names).
- Define the communication protocol and adapter type (e.g., SOAP, IDoc, File).
- Include transport parameters like URLs, ports, credentials, and Quality of Service (QoS).
- Created and configured in the Integration Directory.
- Tie the business message to a physical system and communication channel.
¶ Relationship Between Abstract and Concrete Interfaces
- Each Concrete Interface is based on exactly one Abstract Interface.
- The Abstract Interface provides the message contract, while the Concrete Interface specifies how and where the message is sent or received.
- This separation allows the same Abstract Interface to be reused in multiple Concrete Interfaces with different communication protocols or systems, enhancing flexibility and modularity.
¶ Working with Abstract and Concrete Interfaces: Step-by-Step
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Define Abstract Interface in ESR:
- Model message types and data structures.
- Define service interfaces specifying inbound or outbound operations.
- Establish message exchange patterns (e.g., synchronous, asynchronous).
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Create Mappings (Optional):
- Develop graphical or Java/XSLT mappings to transform messages between different structures if required.
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Configure Concrete Interfaces in Integration Directory:
- Assign the Abstract Interface to sender and receiver communication channels.
- Define sender and receiver business systems.
- Specify adapter types, transport protocols, and connection details.
- Set processing parameters like QoS, retries, and security.
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Configure Integration Scenarios:
- Use the concrete interfaces within Integration Directory to create integrated business processes and routing logic.
¶ Benefits of Separating Abstract and Concrete Interfaces
- Reusability: The same Abstract Interface can serve multiple communication scenarios.
- Flexibility: Concrete details can be changed without modifying the business message structure.
- Clear Separation: Keeps business logic (message structure) distinct from technical implementation (protocols, systems).
- Maintainability: Simplifies updates, testing, and troubleshooting by isolating design-time and runtime aspects.
Consider a Purchase Order (PO) interface:
- Abstract Interface: Defines the PO message structure and operations, agnostic of any sender or receiver system.
- Concrete Sender Interface: Configured with details of the SAP ERP system sending the PO, using the IDoc adapter.
- Concrete Receiver Interface: Configured with details of a third-party logistics system, using SOAP adapter and HTTPS protocol.
This setup allows changing the receiver system or protocol without impacting the core message structure.
Mastering the use of Abstract and Concrete Interfaces is key to building scalable and maintainable integration solutions in SAP PI/PO. The clear division between business message design and technical communication enables flexibility, promotes reuse, and simplifies complex integration scenarios.
By properly leveraging these interface types, organizations can optimize their integration landscape for both current needs and future adaptability.