Metadata for the Description and Discovering of Services

The service infrastructure of Oracle utilizes metadata standards as a means for describing the messages and protocols that are utilized by web services. Such metadata standards are then used by infrastructure and applications as a means for guaranteeing that services will be able to interoperate based on the requirements placed on users by the services. Vital metadata standards include UDDI, WSDL, WS MetadataExchange, and WS Policy.

WSDL is used to describe messages that a service is capable of sending and receiving. It is the most basic contract language that is utilized to describe business functionality that is offered by a particular service.

WS Policy describes the quality of service requirements and characteristics that are associated with a particular service. Such policies tend to describe a service’s security requirements, optimizations that such services as MTOM are capable of supporting, and whether the service utilizes WS ReliableMessaging. Oracle Web Services Policy Manager is the provider of the tools for building and enforcing policies for Oracle Fusion Middleware.

WS MetadataExchange can be thought of as a handshake protocol that allows users to retrieve WS Policy and WSDL documents that are associated with a service.

UDDI is a model that is utilized by service registries. It is known for providing a common repository of metadata about various services that may be utilized to discover what services are available and then select which services are available to use for the building of new composite services and business processes.

Service Implementation

JAX WS is a standard that is defined in the Java community process that is descriptive of how Java developers may go about creating Web services. Like a lot of the newer Java EE specifications, JAX WS eliminates a lot of the complexity that is associated with the development of web services. For instance, JAX WS provides a very simple model for the implementation of business logic, while exploding the contract as a WSDL interface via the use of annotations on the code of implementation. Through the leveraging of JAX WS, developers are then able to build portable services by utilizing skills that can be applied widely across many different products.

You can find very good article with sample code annotated Java class for web services

Oracle Fusion

Oracle Fusion Middleware combines all the key standards that have been discussed thus far together in to a common service infrastructure. Such a service infrastructure is in turn shared throughout the entire middleware platform. This guarantees a common, interoperable basis for the deployment of the next generation of enterprise applications. Developers can thus configure services that have been deployed upon the service infrastructure in order to leverage such standards through the use of a composite service descriptor, as has been described the Service Component Architecture standard. This model presents an elegant mechanism for the combination of all the standards discussed so far in to a simple description of services as well as their relationships.

As standards are considered to be the starting point for all interoperability, Web services that are constructed with Oracle Fusion Middleware tend to conform to two profiles delineated by the main industry consortium on interoperability. One is the WS Interoperability Basic Profile 1.1, while the other is the Basic Security Profile 1.0. What is more, Oracle makes extensive use of testing frameworks that are focused solely on interoperability with major vendor platforms as well as open source web services stacks. Oracle also participates in interoperability events that are open to the public where vendors can validate interoperability among platforms. This gives application developers a foundation upon which they may then build interoperable services that can be readily coordinated in the formation of composite applications.

The Oracle Strategy

Oracle Fusion Middleware is renowned for providing comprehensive infrastructures and tooling for the deployment and development of service oriented applications that are based on J2EE applications, as well as ESB flows and BPEL processes. Through the usage of unified Service Oriented Architecture tools that are provided in Oracle Jdeveloper, it is vital to bring services together in to a new generation of business processes and composite services.

Once they are built, the services can then be deployed to an SCA based service infrastructure, which is a run time environment that renders a common bus for both network connectivity and the delivery of messages. The service infrastructure is then shared across the Fusion Middleware Platform, allowing single infrastructure to provide such services to the full product suite.

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