/// <summary>
/// transition to the next state in execution
/// </summary>
/// <param name="nextState">the name of the state to transition to</param>
public void Transition(string nextState)
{
// if there's no current state running, and we've somehow tried to transition, throw an exception
if (currentState == null)
{
throw new NullReferenceException("no current state");
}
// get the next state from the current state's list of transitions
State next = currentState.Transitions[nextState];
// if no state was returned, then the current state cannot transition to that state
if (nextState == null)
{
throw new NullReferenceException("no state to transition to");
}
// leave the current state
currentState.execLeave();
// set the state objects correctly
previousState = currentState;
currentState = next;
// enter the (new) current state
currentState.execEnter();
}
