The structure of TCPN model is stored in an object of class CP Net. The user is supposed to create TCPN model by creating Place, Transition, Input Arc and Output Arc objects together with guards and inscriptions implementing I Guard and I Expression interfaces. For efficiency of simulation it is however vital, to provide various information about the net as quickly as possible, without the need to repeatedly exploit computationally intensive graph algorithms. Therefore,after user provided the model, the CP Net class performs additional processing in order to cache data concerning model structure and efficiently provide required information for the simulator. On the basis of the list of transitions provided by the user the CP Net class creates list of all places in the model (as Java Array List). Additionally it caches Petri net structure in an array analogous to graph incidence matrix. The internal structures are filled by method init of class CP Net that should be called after the CP Net object is provided with the list of objects representing TCPN transition. The proposed solution allows to reconcile requirements concerning efficient access to different aspects of TCPN model while simulation, with the need to ensure consistency between different representations. Obviously the structure of the Petri net cannot be changed after the call to the initmethod.