public void Act(Election message)
{
// Every time a process sends or forwards an election message, the process also marks itself as a participant.
if (ProcessHeader(message.Header, message))
{
return;
}
//If the UID in the election message is smaller, the process unconditionally forwards the election message in a clockwise direction.
if (string.Compare(message.Node, _options.Address) < 0)
{
isParticipant = true;
var e = new Election
{
Node = message.Node,
Header = CreateHeader()
};
PassMessage(node => node.StartElection(e));
}
//If the UID in the election message is larger
else if (string.Compare(message.Node, _options.Address) > 0)
{
//and the process is not yet a participant, the process replaces the UID in the message with its own UID, sends the updated election message in a clockwise direction.
if (!isParticipant)
{
isParticipant = true;
var e = new Election
{
Node = _options.Address,
Header = CreateHeader()
};
PassMessage(node => node.StartElection(e));
}
//If the UID in the election message is larger, and the process is already a participant
//(i.e., the process has already sent out an election message with a UID at least as large as its own UID),
//the process discards the election message.
}
else
{
//If the UID in the incoming election message is the same as the UID of the process, that process starts acting as the leader.
//The leader process marks itself as non-participant and sends an elected message to its neighbour announcing its election and UID.
isParticipant = false;
leaderId = _options.Address;
var e = new Elected
{
Header = CreateHeader(),
Node = _options.Address
};
PassMessage(node => node.WonElection(e));
}
}
public void Act(Elected message)
{
if (ProcessHeader(message.Header, message))
{
return;
}
//When a process receives an elected message, it marks itself as non-participant, records the elected UID, and forwards the elected message unchanged.
if (message.Node != _options.Address)
{
isParticipant = false;
leaderId = message.Node;
//When the elected message reaches the newly elected leader, the leader discards that message, and the election is over.
PassMessage(node => node.WonElection(new Elected
{
Header = CreateHeader(),
Node = message.Node
}));
}
}
public override string ToString() =>
$"Elected: {Elected.FullName()}. Other: {Other.FullName()}";