Readers send input events to the router, which distributes them, as needed, to its agents before sending them to the various output channels. Table 9.1 gives the mapping from each agent to the request and message class types for which it bears responsbility, though in many cases no analysis is currently performed, with the router acting only as a multiplexer to relay events to the downstream receivers. The two agents Runner and Bookkeeper are closely coupled in function, as suggested by the lack and multiplicity of message types for the first and second, respectively, and the implementation of these two agents is in particular likely to change significantly in the future. The agent classes are arranged according to the derivation hierarchy of Figure .
Bill Pippin 2010-01-14