@Override
public void handleAccepted(PaxosMessage proposal) {
ensureSize(chosen, proposal.getInstanceNum() + 1); // Prevent NPE
if (chosen.get(proposal.getInstanceNum()) != null)
return; // Something has already been chosen so I dont care anymore.
List<PaxosMessage> acceptedVotes = proposalAcceptedVotes.get(proposal.getInstanceNum());
if (acceptedVotes == null) {
acceptedVotes = new ArrayList<PaxosMessage>();
acceptedVotes.add(proposal);
proposalAcceptedVotes.put(proposal.getInstanceNum(), acceptedVotes);
} else {
for (PaxosMessage acceptedVote : acceptedVotes) {
if (proposal.getProposerId() == acceptedVote.getProposerId())
return; // This person is reaffirming their acceptance of this instances proposal.
}
acceptedVotes.add(proposal);
proposalAcceptedVotes.put(proposal.getInstanceNum(), acceptedVotes);
}
// handle being chosen
if (proposalAcceptedVotes.get(proposal.getInstanceNum()).size() >= serverSet.getQuorumSize()) {
onChosen(proposal);
}
}
@Override
public void handlePrepareResponse(PaxosMessage response) {
if (!prepareResponseFrom.contains(response.getProposerId()))
prepareResponseFrom.add(
response.getProposerId()); // This is a new server accepted our prepare request.
List<ChatMessage> remoteAccepted = (List<ChatMessage>) response.getValue();
for (int i = 0; i < remoteAccepted.size(); i++) {
if (chosen.size() > i && chosen.get(i) != null) continue;
if (remoteAccepted.get(i) != null) {
propose(
new DefaultPaxosMessage(
i, nextPropose, id, PaxosMessageType.PROPOSE, remoteAccepted.get(i)));
if (i > nextInstance) nextInstance = i;
}
}
}
/**
* Adds nulls to the end of list until it is at least size.
*
* @param list
* @param size
*/
private void ensureSize(List list, int size) {
while (list.size() < size) {
list.add(null);
}
}