Service Implementation Pattern

• Development of a completely new service implementation to meet a business requirement.
• Wrapping an existing application with a service interface.
• Composing several existing services into a more complex service.

The purpose of this pattern is to show how underlying services can be built to fit into the Service Oriented-Architecture (SOA), Service Orchestration, and Enterprise Service Bus (ESB) patterns.

Wrapping existing applications may be facilitated through the use of adapters or plug-ins provided by the ESB. Furthermore, composition of existing services to produce a new service may be facilitated through the use of the service orchestration capabilities provided by the ESB.

Please view the Service Implementation Pattern below:

• Wrapping of existing application functionality provides for incremental transition to SOA while leveraging investments.
• Composition of services can accelerate implementation and can provide for a more flexible business rules and process flows based on service orchestration.

• There are multiple approaches to meeting the requirements for a new service. The appropriate option should be selected to maximize reuse while meeting the service-levels required by the new service.

Recommended Usage

• New Service Implementation – This approach should be used if there is no existing functionality that can be leveraged to deliver the capability or savings in terms of operational or maintenance costs can be realized by implementing the service new and retiring an existing application.
• Wrapped Existing System – This approach should be used if there is existing functionality that can meet the performance, reliability, availability and security requirements for the service being developed.
• Composite Service – This approach should be used if there are existing services in place that can be leveraged to build a composite service to meet the requirements for the new service.