Behavioural models are used to describe the overall behaviour of a system. The behavioural model indicates how software will respond to external events or stimuli. To create the model, you should perform the following steps:
1. Evaluate all use cases to fully understand the sequence of interaction within the system.
2. Identify events that drive the interaction sequence and understand how these events relate to specific objects.
3. Create a sequence for each use case.
4. Build a state diagram for the system.
5. Review the behavioural model to verify accuracy and consistency
Two types of behavioural model are:
Data processing models that show how data is processed as it moves through the system and State machine models that show the systems response to events. These models show different perspectives, so both of them are required to describe the system’s behaviour.
Data Processing Model
Data flow diagrams (DFDs) may be used to model the system’s data processing. These show the processing steps as data flows through a system. DFDs are an intrinsic part of many analysis methods. It is Simple and intuitive notation that customers can understand. It shows end-to-end processing of data. DFDs model the system from a functional perspective. It is helpful to develop an overall understanding of the system.
State machine Model
These model the behaviour of the system in response to external and internal events. They show the system’s responses to stimuli so are often used for modelling real modelling real-time systems. State machine models show system states as nodes and events as arcs between these nodes. When an event occurs, the system moves from one state to another. State charts, an integral part of the UML is used to represent state machine models.
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