Information Technology Reference
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Fig. 2.
MVC architecture with extended agent-based controller
the controlling components are changed. Figure 2 shows the MVC architecture
including Human Agent Interface and the MAS. The controller is modified in a
way, that the HAI-Agent can act as mediator and the application logic is realised
by the MAS. For this, incoming requests (1) are forwarded to the agent-system.
Requests are either triggered by method calls and directly sent to the HaiAgent-
Bean or triggered by web service calls and sent to the HaiWebserviceBean which
forwards them to the HaiAgentBean. If necessary the HaiDBBean is involved
to provide required data from a connected database. The request will then be
converted into an agent message, with additional data. The HAI-Agent proceeds
with the search for agents which are able to process the request. A definition of
thenatureofarequestisgivenbytheuser interface as parameter to the HaiA-
gentBean. If a fitting agent is located, the previously generated agent message
will be forwarded (2). Otherwise a failure code will be returned. The advantage
of this principle is the transparent communication between UI and the MAS for
the agent developers. Communication from the user interface can be handled
just as any other communication. The focus in implementing agent systems thus
remains on the agents themselves and does not additionally comprise user inter-
face topics. After the agent has provided an answer to the redirected request,
the result is sent back to the HAI-Agent (3). The HAI-Agent then updates the
data model if necessary (4) and notifies the view on potential changes, which are
applied automatically (5).
For web interfaces the structure is slightly different since the underlying
request-response model does not support active views. The controller compo-
nent has to specify a suitable view for the modified data — this structure is
commonly called: Model 2 paradigm [5]. If HAI is used in this context, incoming
data is stored in combination with an ID, which can be retrieved by a third
controller component (such as a servlet) which defines the associated view.
