public void ChangeState(MessageState newState)
{
MessageState currentState;
if (!this.TryChangeState(newState, out currentState))
{
throw new InvalidOperationException(
string.Format("Invalid state change from {0} to {1}", currentState.Name, newState.Name));
}
}
public bool TryChangeState(MessageState newState, out MessageState oldState)
{
var currentState = this.state;
while (true)
{
if (!currentState.CanTransitionTo(newState))
{
oldState = currentState;
return false;
}
Interlocked.CompareExchange(ref this.state, newState, currentState);
if (this.state == newState)
{
oldState = currentState;
return true;
}
}
}
public bool CanTransitionTo(MessageState newState)
{
return allowedTransitions.Contains(newState.Name);
}
public MessageStateMachine(MessageState initialState)
{
this.state = initialState;
}
