Each person in the use case diagram corresponds to a role such as defendant, plaintiff, judge, clerk. A single person might be a defendant in one civil case and a plaintiff in another. A court clerk might be sued when she inadvertently collides into someone when on vacation. We consider each stereotypical role as a separate actor, even if occasionally, a single person might fill both roles. They perform sequences of related actions with the system, such as file a lawsuit or file a motion.
Some actions have common features with others.
For example, there might be certain identity checks and receiving an acknowledgement that would be in common with all electronic filing activities. We use the extends stereotype to show these. However, only a plaintiff engages in the activity of filing a lawsuit. The statechart will be explained in the example below. The others are not immediately relevant to the activities of the Legal XML group.