Chapter 10. Web Services

Web services are a key contributing factor in the way Web commerce is conducted today. Web services enable applications to communicate by sending small and large chunks of data to each other.
A web service is essentially a software application that supports interaction of applications over a computer network or the world wide web. Web services usually interact through XML documents that map to an object, computer program, business process or database. To communicate, an application sends a message in XML document format to a web service which sends this message to the respective programs. Responses may be received based on requirements, the web service receives and then sends them in XML document format to the required program or applications. Web services can be used in many ways, examples include supply chain information management and business integration.
JBossWS is a web service framework included as part of the JBoss Enterprise Application Platform. It implements the JAX-WS specification that defines a programming model and run-time architecture for implementing web services in Java, targeted at the Java Platform, Enterprise Edition 5 (Java EE 5). Even though JAX-RPC is still supported (the web service specification for J2EE 1.4), JBossWS does put a clear focus on JAX-WS.

Warning

JAX-RPC is not supported for JBoss Web Services CXF Stack.

10.1. The need for web services

Enterprise systems communication may benefit from a wise adoption of web service technologies. Focusing attention on well designed contracts allows developers to establish an abstract view of their service capabilities. Considering the standardized way contracts are written, this definitely helps communication with third-party systems and eventually supports business-to-business integration; everything is clear and standardized in the contract the provider and consumer agree on. This also reduces the dependencies between implementations allowing other consumers to easily use the provided service without major changes.
Other benefits exist for enterprise systems that incorporate web service technologies for internal heterogenous subsystems communication as web service interoperability boosts service reuse and composition. Web services eliminates the need to rewrite whole functionalities because they were developed by another enterprise department using a different software language.