public void DepartFrom(ILocation location)
{
if (null == location)
{
throw new ArgumentNullException("location");
}
VoyageState stateBeforeTransition;
VoyageState previousState = CurrentState;
do
{
stateBeforeTransition = previousState;
VoyageState newValue = stateBeforeTransition.DepartFrom(location);
previousState = Interlocked.CompareExchange <VoyageState>(ref this.CurrentState, newValue, stateBeforeTransition);
}while (previousState != stateBeforeTransition);
if (!previousState.Equals(this.CurrentState))
{
VoyageEventArgs args = new VoyageEventArgs(CurrentState.LastKnownLocation, CurrentState.NextExpectedLocation);
EventHandler <VoyageEventArgs> handler = Departed;
if (null != handler)
{
handler(this, args);
}
}
}
public void StopOverAt(ILocation location)
{
if (null == location)
{
throw new ArgumentNullException("location");
}
// Thread safe, lock free sincronization
VoyageState stateBeforeTransition;
VoyageState previousState = CurrentState;
do
{
stateBeforeTransition = previousState;
VoyageState newValue = stateBeforeTransition.StopOverAt(location);
previousState = Interlocked.CompareExchange <VoyageState>(ref this.CurrentState, newValue, stateBeforeTransition);
}while (previousState != stateBeforeTransition);
if (!previousState.Equals(this.CurrentState))
{
VoyageEventArgs args = new VoyageEventArgs(previousState.LastKnownLocation, previousState.NextExpectedLocation);
EventHandler <VoyageEventArgs> handler = Stopped;
if (null != handler)
{
handler(this, args);
}
}
}