Bridging Agent Theory and Object Orientation: Importing Social Roles in Object Oriented Languages

Social roles structure social institutions like organizations in Multi-Agent Systems (MAS). In this paper we describe how to introduce the notion of social role in programming languages. To avoid the commitment to a particular agent model, architecture or language, we decided to extend Java, the most prominent object oriented programming language, by adding social roles. The obtained language allows an easier implementation of MAS's w.r.t. the Java language. We also show that many important properties of social roles, studied in the MAS field, can be applied to objects. Two are the essential features of social roles according to an analysis reported in the paper: social roles are defined by other entities (called institutions), and when an agent plays a role it is endowed with powers by the institution that defines it. We interpret these two features into the object oriented paradigm as the fact that social roles are objects, which are defined in and exist only inside other objects (corresponding to institutions), and that, through a role, external objects playing the role can access to the object (institution) the role belongs to.