UDDI Registry架构及作用
UDDI Schema Objects - The UDDI specification comes equipped with an XML schema for its many data structures. jUDDI employs XML-binding technology (JAXB) to generate objects from the schema (contained within the WSDL) that are then used as the arguments for the UDDI Interface layer. These objects needn't originate from XML – they can also be instantiated directly to make UDDI calls directly in java code.
Validation – the validation layer reads the schema object input from the UDDI interface layer and, based on rules defined in the specification, makes sure the input is valid for the given UDDI method. Failed validation results in an exception and an immediate return from the method call.
Mapping – the mapping layer is responsible for mapping the UDDI schema objects to the persistence layer model. For all intents and purposes, the mapping layer simply copies data from a schema object to the similar model object. This occurs in both directions, as input objects must be mapped to the model to perform the necessary logic and results obtained from the call must be mapped back to the schema as output to the caller.
Business Logic - the business logic layer is responsible for performing all the business logic associated with the UDDI calls. The logic layer works with objects from the persistence layer and generally consists of querying the model based on user input.
Persistence - the persistence layer, as its name implies, is responsible for persisting registry data to a storage medium. To this end, a third-party persistence service that implements the Java Persistence API (Apache OpenJPA, Hibernate) is utilized to manage transactions with the storage medium and also to facilitate the plugging-in of various storage types. By default, jUDDI is packaged with Apache OpenJPA as the persistence provider and Apache Derby as the storage medium. This can easily be configured. ??
