Software Design 2e - DIM

162Some design representationsFigure 7.29component-namecomponentNotation used for a component (UML).DisplayControlinterfacesinterface-name1interface-name2updateScreenAccountInterfaceUserValidationgetAccountStatusFigure 7.30UML component diagram for part of a bank autoteller.While this is a more specific view of the term component than is used in the widersoftware engineering context (and will be used later in this book), we will confine ourselvesto using this definition within this section. Figure 7.29 shows the basic UMLnotation for a component. Such a component has interfaces that are provided for useby other components, and interfaces that are required to be supplied from other components;both of these are represented by a small circle attached by a line, with anidentifier that represents the given interface.Because components supply information to each other, the details of the interfacesmay need to be available when a given component is compiled, or when a set of componentsare linked together. Such dependencies can also be shown on the diagram bydashed arrows, which may be labelled to show the details of the dependency concerned(usually in terms of binding time, as in or ). Figure 7.30 showsan example of a component diagram that describes some of the elements forming animplementation of a bank autoteller.