This extension point should be used when the customization developer needs additional business logic for an application service. This additional logic, which is not available as part of the API product functionality, but could be a client requirement. For these purposes, two hooks are provided in the application code:

Pre-extension hook

This extension point is available in application service before it performs any validations and executes business logic. This hook can be important in the following scenarios:

• Additional input validations
• Execution of business logic, which necessarily has to happen before going ahead with normal service execution.

Post-extension hook

This extension point is available in the application service after it has executed business logic. This hook can be important in the following scenarios:

• Output response manipulation
• Custom data logging for subsequent processing or reporting.

Both ‘pre’ and ‘post’ service extensions are available in the application service layer (also known as the ‘app’ layer) of OBAPI.

This hook in implemented using service extension executor and service extensions. These components are explained in detail below. Customization developer can use these components suitably based on the requirement.

Below class diagram depicts the relationship between application service, extension executor and extensions. The diagram considers a sample ‘create’ method in application service.