8.8. Composition
A class can have references to objects of other classes as members. Such a capability is called composition and is sometimes referred to as a has-a relationship. For example, an object of class AlarmClock needs to know the current time and the time when it is supposed to sound its alarm, so it is reasonable to include two references to Time objects as members of the AlarmClock object.
Software Engineering Observation 8.9
| One form of software reuse is composition, in which a class has as members references to objects of other classes. |
Our example of composition contains three classes—Date (Fig. 8.7), Employee (Fig. 8.8) and
Get Java™ How to Program, Seventh Edition now with the O’Reilly learning platform.
O’Reilly members experience books, live events, courses curated by job role, and more from O’Reilly and nearly 200 top publishers.
