Overview of the RosterApp Application

The RosterApp application maintains the team rosters for players in sports leagues. The application has five components. The RosterAppClient component is a application client that accesses the RosterBean session bean through the bean's remote interfaces. RosterBean accesses three entity beans--PlayerBean, TeamBean, and LeagueBean--through their local interfaces.

The entity beans use container-managed persistence and relationships. The TeamBean and PlayerBean entity beans have a bidirectional, many-to-many relationship. In a bidirectional relationship, each bean has a relationship field whose value identifies the related bean instance. The multiplicity of the TeamBean-PlayerBean relationship is many-to-many: Players who participate in more than one sport belong to multiple teams, and each team has multiple players. The LeagueBean and TeamBean entity beans also have a bidirectional relationship, but the multiplicity is one-to-many: A league has many teams, but a team can belong to only one league.

Figure 27-1 shows the components and relationships of the RosterApp application. The dotted lines represent the access gained through invocations of the JNDI lookup method. The solid lines represent the container-managed relationships.

RosterApp J2EE Application

Figure 27-1 RosterApp J2EE Application