Simulation of queueing network in Java

This article deals with the object model of a queuing network (subset of discrete systems) and application for visual design (QNetSim).The queueing network is represented as a directed evaluated graph. There are two types of nodes in the graph: service centers and sources of customers. Service centers consist of several servers and a queue. Edges between nodes represent transitions of customers between service centers. The object model of the queuing network duplicates the structure of the graph. The model covers all attributes of the graph and includes also classes of customers. Design patterns were used during the construction of the model. The main reason was to speed up development and increase reusability of the final solution. Nodes of the graph have a simple interface, this is why it is easy to extend the model with new or modified types of nodes.The simulation core works with the model of the queuing network and offers the possibility of planning and executing customer processes. The model contains statistic data of the last executed simulation.Graphical user interface offers visual design and simulation of the network.