Migration of a Chosen Architectural Pattern to Service Oriented ...

Chapter 5. Guidelines 107Result Context The system has one main way of communication. Eachservice of the system provide interface for this way of communication.3. Name Canonical SchemaProblem Many services perform operation on the same data that aremodeled differently by different vendors or teams. Those differences increasedevelopment efforts and make design more complex. Additionally,the transformation between different models introduces performance drop.ContextApplication uses communication protocolsForces(a) Schema of the data may change over time.(b) The schema is used in many services from different inventories.(c) Schema needs to be easily extended.Solution The pattern standardizes data model for information within theinventory. The motivation behind the pattern is to avoid translation betweendifferent definitions of the same data and eliminate data definitionredundancy across the systemResult Contextand maintainable.System has a centralized schema that easily accessible4. Name Policy CentralisationProblem Services may require to process individual polices. Policies mayrefer to security, transaction requirements and Quality-of-Services. Replicationof policies across inventories brings redundancy and problems withsynchronization of changes to the policies.ContextThe system is composed of services that need to process policies.Forces(a) Number of services using policies is not fixed(b) The policies change over time