MOST ANALYSTS, VENDORS, AND AUTHORS THESE DAYS RECOMMEND ONLY ONE APPROPRIATE WAY TO realize a SOA landscape: with Web Services.
In this chapter, I will discuss Web Services from a conceptual point of view, provide an overview of their current state, and discuss how to use them in practice. My aim will be to improve your understanding of Web Services and to clarify some of the tasks and efforts that are necessary when using them.
Web Services are widely regarded as the way SOA should be realized in practice. For example, [Erl05] states that “Contemporary SOA represents an...architecture that promotes service-orientation and is comprised of...services, implemented as Web services” (see “Thomas Erl’s Definition of SOA in ‘Service-Oriented Architecture’” in Chapter 2 for the complete quote). And [Gartner05] predicted:
By 2006, more than 60 percent of the $527 billion IT professional services market will be based on the exploitation of Web services standards and technology.
Of course, as is so often the case with SOA, what all of this means is not very clear. What are Web Services, in practice? Let’s take a look at the definition given in an interview between Kirk McKusick (KM), former head of the UC Berkeley Computer Systems Research Group, and Adam Bosworth (AB), a senior manager at Microsoft in the late 1990s who was one of the people most central to the effort to define Web Services. This interview was published in the first ...