Web services promise to lower the costs of integration and help legacy applications retain their value. This article introduces you to the basics of Web services, how they reduce costs and how you can use them to integrate mainframe applications with other enterprise applications.
Web services are platform-independent interfaces that allow communication with other applications using standards-based Internet technologies, such as HTTP and XML. They provide an opportunity for organizations to reduce the costs and complexities of application integration inside the firewall and create new possibilities for legacy applications to participate in e-business.
Proponents of Web services talk about a new era of interoperability. However, haven’t we heard all of this before? Applications using standardized interfaces such as Common Object Request Broker Architecture (CORBA), Java 2 Enterprise Edition (J2EE) or Microsoft’s Distributed COM (DCOM) were supposed to deliver the same benefits but fell short. Nonetheless, each of those interfaces has platform-specific and vendor-specific components that keep it from being technology-neutral. Therefore, companies that adopted CORBA interfaces were not immediately compatible with partner networks that used either DCOM or J2EE. However, Web services are standards-based, platform-independent, and the course Web services take is controlled by independent standards bodies, not individual corporations pushing their own technologies. Web services simplify the complexity of integration by reducing the number of Application Programming Interfaces (APIs) and the number of data formats to one.
Web services sound promising for new applications that have support for Internet technologies built-in, but what about legacy systems? How can they benefit from Web services integration and what does it take to integrate legacy applications as Web services? First, let’s discuss Web services in general, and then we will delve into their relevance to legacy applications.
Standards-Based and Platform-Independent
While applications have been able to communicate using Internet technologies for years, only recently have standards evolved to allow distributed applications to talk to each other. Web services depend upon three key open standards to allow them to communicate regardless of the hardware they run on, operating system they run under, or programming language used to produce them (see Figure 1).
Building on the foundation provided by Simple Object Access Protocol (SOAP), Web Service Definition Language (WSDL), and the Universal Description, Discovery and Integration (UDDI) standard, there are emerging standards for handling complex business process workflow, authentication, and message integrity. These transactions span multiple enterprises and long-lasting transactions to ensure that the outcomes of the transactions are reliable. Underlying all of this is the use of XML as the message format and a standard protocol such as HTTP as the transport method.
Standards-based components diminish the costs and skills required to integrate applications within an organization or between partners. Because there is widespread vendor support for Web services, interoperability among vendor solutions will improve. However, the greatest benefits of standards-based Web services for developers and administrators are reduced complexity and increased flexibility of integration architectures.
Reducing Complexity and Increasing e-Business Flexibility