Implicitly an object can act as a client merely by requesting services from other objects as part of the process whereby it services its own clients. The relation between a client object and its server is that of collaborations . New objects can be created. An object that can only be accessed by clients by issuing requests . Beware of confusing encapsulation with information hiding .
Encapsulation is an implementation option.
An object created by wrapping an existing structure or process that is not an object within an appropriate interface . An object that restricts the ability of specific clients to request its services . Describes a set of potential requests that identify the object as a parameter . A lattice in which higher interfaces are more general and accept requests that are also accepted by conforming objects . An identifiable entity with an associated predicate defined of values.