Using an event sequence, the commands must not extend SequenceCommand and hence should not set up a nextEvent and dispatch it. This means that your commands can be used in a number of different sequence scenarios without letting the commands know they are chained.

The sequencing works by setting up a trigger for an event, based on a property change in an object. This property change will normally be executed by a command.

var sequence:EventSequence = new EventSequence();
  
  sequence.addSequenceEvent(LoadSessionEvent, ["4562-54289778-56985412"]);
  
  sequence.addSequenceEvent(LoadExamEvent,
   [new Property(ModelLocator.getInstance(), "session", "examId")],
   [new Property(ModelLocator.getInstance(), "session")]);
  
  sequence.addSequenceEvent(LoadCandidateEvent,
   [new Property(ModelLocator.getInstance(), "session", "candidateId")],
   [new Property(ModelLocator.getInstance(), "exam")]);
  
  sequence.dispatch();

In this example, 3 events are chained. (This sequence is used to load the session of an exam, the exam itself and the candidate)

The first event is the LoadSessionEvent that gets the id of a session as its constructor argument. The command that is executed by this event will fetch an exam session and store it in the session property of the ModelLocator. Since this is the first event, it does not define any triggers for the next event.

The second event is the LoadExamEvent. This event takes the id of the exam as its constructor argument, fetches an exam and stores it in the exam property of the ModelLocator. Notice the 3rd argument that defines the trigger for this event. It is defined a Property object that contains a reference to the session property in the ModelLocator. This means that this event will be dispatched when the session property has been set. The examId is also passed in as a property and will be evaluated when the sequence creates the next event.

The third event is the LoadCandidateEvent. This event takes the session.candidateId as its constructor argument and will be dispatched when the exam property is set on the ModelLocator.