Service composition: the problem of composing autonomous services to achieve new functionality, is generating
considerable interest in recent years in several computer science communities. Service composition has the potential to reduce
development time and effort for new applications. The web is a particularly interesting domain for service composition for
several reasons. Firstly, increasing numbers of interesting services are moving online and the web is fast transforming from a
collection of static pages to a provider of numerous useful services. Another reason is that web services conform to the standard
HTTP protocol which makes it (relatively) easier to integrate them into a common framework. Third, because the web has several
independent service providers providing related services, there is an inherent need for composing complementary services
provided by independent providers to achieve the end-user's needs.
The service composition problem is particularly challenging because web services fall into many categories and composing
such a diverse set of services may require several different tools, techniques, and technologies. In this paper, we propose one
such toolset: SWORD. SWORD is a toolset that allows service developers to quickly compose base web services to realize new
composite web services. SWORD can compose information providing services (such as the web services providing information
about people, movies, theaters, restaurants, etc) and a class of other services (such as email and image conversion services). The
key idea behind SWORD is as follows