Five Candidate Patterns Promoted To The SOA Patterns Master List

 Five new design patterns were promoted from the candidate list to the master list on the community site of SOA Patterns published by Prentice Hall. These new patterns will be published in the upcoming SOA with REST book

The patterns that made the cut are:

Apart from Entity Linking, the remaining design patterns are self explanatory. Instead of the common practise of embedding entity relationship information in composition services, the Entity Linking pattern prescribes responding with links to related entities by entity services themselves. As a result consumer services can discover the entire entity relationship model as they navigate the links embedded in the responses from the entity services. This decoupling from the composition service alleviates the burden of updating the service to reflect entity relationship changes with time. Lightweight Endpoint and Reusable Contract patterns should ideally be used in conjunction with this design pattern to facilitate link navigation.

Inspired by DNS, the Content Distribution Network (CDN) pattern is a service replication pattern that leverages Brewer's CAP theorem to improve availability at the cost of consistency. Based on HTTP's Content Negotiation mechanism, the Content Negotiation pattern recommends the usage of media type as metadata in the service request and response envelopes to enable delivery of different media types using the same service capabilities. Endpoint Redirection adds permanent or temporary redirection capability to an outdated service to respond to a consumer with a redirection link to an updated version of the service. Apart from wasted runtime resources for repeated permanent redirections, the redirection link in the response is questionable from a security perspective in case the outdated service is compromised. Response caching adds caching at the messaging layer and utilizes caching metadata to prevent transmission of stale responses to redundant requests.