An Accept Change Structural Feature Event Action is an Accept Event Action that waits for a Change Structural Feature Event. The Event will be sent to an object when the value of a specified Structural Feature on the Event changes. When the Accept Change Structural Feature Event Action is activated, the simulation stays on the Action until it accepts the Change Structural Feature Event that will be sent once the value of the specified Structural Feature changes. The following figure shows the Accept Change Structural Feature Event Action that waits for the Change Structural Feature Event of value property, in this example, time.


An Accept Change Structural Feature Event Action in an Activity Diagram
An Accept Change Structural Feature Event Action in an Activity diagram.

When the value of the value property time changes, the Accept Change Structural Feature Event Action will be activated. The token that flows through the pin before is the old value of the value property time and the token that flows to the pin after is the current value of the value property time. Cameo Simulation Toolkit will then simulate the next Action.