Extending the Service Domain of an Interactive Queue

An interactive queue is a software component which stores data following a first-in / first out strategy. The regular behaviour of an interactive queue captures all input streams of enter-queue and de-queue commands which do not lead to a buffer underflow. We investigate the behaviour of interactive queues for input streams outside the service domain. We specify a fault sensitive queue, a fault tolerant queue, a robust queue, and a fault correcting queue as stream functions. We implement the different versions by state transition machines introducing a data state and a control state. Beyond the particular application, we provide adequate notions and high-level concepts for modeling services of interactive components in a functional setting.