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IADIS International Conference WWW/Internet 20102.2.2 TrailM Server(a) TrailM ServerFigure 2. The TrailM architecture(b) TrailM ClientSome of the TrailM Server basic tasks are to manage the entities’ trails and to enable application querying thetrails. To perform these functions, we designed the TrailServices module (see Figure 2a, which presents theTrailM Server architecture). The TrailServices provides basic services to manage the trails and, moreover,enables applications building their own specialized services according to their needs.The basic services perform generic tasks which are considered strategic for the management of the serverand the trails. These services are organized into three groups: ManageTrail, ComposeTrail, and QueryTrail.The ManageTrail group supports the services used for the control and management of the applications. TheComposeTrail group supports the services used for the trails composition. In this group stand out the servicerelated to the sending of ptrails in the trailpoint process. The QueryTrail group contains the services thatallow queries related to the trails.TrailM Server enables applications adding to the model their own specialized services, which can becomposed of basic services. Sect 3.2 describes four specialized services created to support the discovery ofdeal opportunities guided by trails. The server has a database to store information of the entities, the trails andtheir related content. The entities table stores identification data of the entities related to the trails that arebeen managed. The trails table stores the ptrails that compose the entities’ trails. The trail related content isstored in the others tables: context, region, event, extension of events and resources (see Figure 3).Figure 3. TrailM databaseSome services can have common functions, for example, to do database query and to manage the trails.For this reason, we designed the TrailManager component, which performs basic operations that can be usedby the services. The TrailManager aims to meet the basic functionality for trail management as the control ofrequests sent to the server, registration and authentication of users, access to the database and, one of its maintasks, the composition of the record for the storage of a ptrail at the trailpoint solicitation moment. TheTrailRepository provides an interface to access the database repository, thus supporting the TrailManager.2.2.3 TrailM ClientThe TrailM Client resides on the mobile device and supports the applications of TrailM. The clientinstantiates and manages the ptrails entities, making the synchronism of applications with TrailM Server. Theclient is organized into three layers (Figure 2b).The top layer is the communication (TrailClientComm) clientto the server. The intermediate layer (TrailClientLocation) handles the communication device with theexternal provider of geographic location. The management layer (TrailClientCore) manages access to devicecapabilities.21