Event-Based Triggers Compound Triggers Actions Initial Transitions Final Transitions Exceptions States States are one of the two primary components of an Object Behavioral Model. The other primary component is a transition . A state of an object represents the status, phase, situation, or activity of an object. An object may be able to experience many different states. Each separate state is modeled.
Transitions allow an object to change from one state to another.
When the behavior of an object causes the object to reach a certain state, that state is said to be enabled or true. If a state is enabled, then a thread of control is currently in that state. Multiple states may be enabled at the same time signifying a multi-threaded or concurrent environment. If an enabled state is a prior state , it may then cause the action of a transition to occur if other necessary prior states are enabled and if the conditions and events of the transition are satisfied. The graphical representation of a state is a rectangle with rounded corners.