protected ManualResetEventSlim WaitForStateChange(RaftEngine node, RaftEngineState requestedState)
{
var mre = new ManualResetEventSlim();
node.StateChanged += state =>
{
if (state == requestedState)
mre.Set();
};
return mre;
}
internal void SetState(RaftEngineState state)
{
if (state == State)
{
return;
}
if (State == RaftEngineState.Leader)
{
_leaderSelectedEvent.Reset();
}
var oldState = State;
if (StateBehavior != null)
{
StateBehavior.Dispose();
}
switch (state)
{
case RaftEngineState.Follower:
case RaftEngineState.FollowerAfterStepDown:
StateBehavior = new FollowerStateBehavior(this, state == RaftEngineState.FollowerAfterStepDown);
break;
case RaftEngineState.CandidateByRequest:
StateBehavior = new CandidateStateBehavior(this, true);
//setting state before calling election because the state may change to leader before
//we set it to CandidateByRequest
AssertStateAndRaiseStateChanged(state, oldState);
StateBehavior.HandleTimeout();
return;
case RaftEngineState.Candidate:
StateBehavior = new CandidateStateBehavior(this, false);
//setting state before calling election because the state may change to leader before
//we set it to CandidateStateBehavior
AssertStateAndRaiseStateChanged(state, oldState);
StateBehavior.HandleTimeout();
return;
case RaftEngineState.SnapshotInstallation:
StateBehavior = new SnapshotInstallationStateBehavior(this);
break;
case RaftEngineState.Leader:
StateBehavior = new LeaderStateBehavior(this);
CurrentLeader = Name;
OnElectedAsLeader();
break;
case RaftEngineState.SteppingDown:
StateBehavior = new SteppingDownStateBehavior(this);
CurrentLeader = Name;
break;
default:
throw new ArgumentOutOfRangeException(state.ToString());
}
AssertStateAndRaiseStateChanged(state, oldState);
}
internal void SetState(RaftEngineState state)
{
if (state == State)
return;
if (State == RaftEngineState.Leader)
_leaderSelectedEvent.Reset();
var oldState = State;
if (StateBehavior != null)
StateBehavior.Dispose();
switch (state)
{
case RaftEngineState.Follower:
case RaftEngineState.FollowerAfterStepDown:
StateBehavior = new FollowerStateBehavior(this, state == RaftEngineState.FollowerAfterStepDown);
break;
case RaftEngineState.CandidateByRequest:
case RaftEngineState.Candidate:
StateBehavior = new CandidateStateBehavior(this, state == RaftEngineState.CandidateByRequest);
break;
case RaftEngineState.SnapshotInstallation:
StateBehavior = new SnapshotInstallationStateBehavior(this);
break;
case RaftEngineState.Leader:
StateBehavior = new LeaderStateBehavior(this);
CurrentLeader = Name;
OnElectedAsLeader();
break;
case RaftEngineState.SteppingDown:
StateBehavior = new SteppingDownStateBehavior(this);
CurrentLeader = Name;
break;
default:
throw new ArgumentOutOfRangeException(state.ToString());
}
Debug.Assert(StateBehavior != null, "StateBehavior != null");
OnStateChanged(state);
_log.Debug("{0} ==> {1}", oldState, state);
}
protected virtual void OnStateChanged(RaftEngineState state)
{
var handler = StateChanged;
if (handler != null)
{
try
{
handler(state);
}
catch (Exception e)
{
_log.Error("Error on raising StateChanged event" + e);
}
}
}
protected ManualResetEventSlim CreateWaitForStateChangeEvent(RaftEngine node, RaftEngineState requestedState)
{
var mre = new ManualResetEventSlim();
node.StateChanged += state =>
{
if (state == requestedState)
{
mre.Set();
}
};
return(mre);
}
