The sequence diagram is the most used of the dynamic models. It has a long and rich history tracing back to, among others, James Rumbaugh's OMT (Object Modeling Technique) methodology. The diagram begins with instances of classes—objects—organized in “swim lanes” across the top. Below each object is a “lifeline,” as Figure 7-3 shows.
Objects are drawn as boxes, with the class name preceded by a colon and then the entire name underlined. This notation can be verbalized as, for example, “any old Customer object.” If a specifically named object is desired, then the colon is preceded with the name of the object—for example, Rene Becnel:Customer, which, verbalized, means “the Rene Becnel object of class Customer.” Figure 7-3