Service definition revisited

The previous chapter provided a basic definition of what a service is. With the design principles provided in this chapter in mind, let's have a look at a formal definition of services according to The Open Group:

Note

The Open Group is a global consortium that enables the achievement of business objectives through IT standards. See: http://www3.opengroup.org/aboutus

A service:

• is a logical representation of a repeatable business activity that has a specified outcome (for example, check customer credit; provide weather data, consolidate drilling reports)

• is self-contained

• may be composed of other services

• is a black box to consumers of the service

Source: http://www.opengroup.org/soa/source-book/soa/soa.htm

This definition fits well with the service principles you have seen in this chapter. The following table maps the definition on our service principles:

Open Group Definition	Applicable Service Principles
A logical representation of a repeatable business activity...