From Communication Histories to State Transition Machines

The black-box view of an interactive component concentrates on the input/output behaviour based on communication histories. The glass-box view discloses the component’s internal state with inputs effecting an update of the state. The black-box view is modelled by a stream processing function, the glass-box view by a state transition machine. We present a formal method for transforming a stream processing function into a state transition machine with input and output. We introduce states as abstractions of the input history and derive the machine’s transition functions using history abstractions. The state refinement is illustrated with two applications, viz. iterator components and an interactive stack.