/// <summary>
/// Sends a leave request to the coordinator
/// </summary>
/// <param name="coord">Address of the coordinator</param>
/// <param name="mbr">Local Address</param>
private void sendLeaveMessage(Address coord, Address mbr)
{
Message msg = new Message(coord, null, null);
GmsHeader hdr = new GmsHeader(GmsHeader.LEAVE_REQ, mbr);
msg.putHeader(gms.getName(), hdr);
gms.passDown(new Event(Event.MSG, msg));
}
/// <summary>
/// Acknowledges leave response.
/// </summary>
/// <param name="mbr"></param>
private void sendLeaveResponse(Address mbr)
{
Message msg = new Message(mbr, null, null);
GmsHeader hdr = new GmsHeader(GmsHeader.LEAVE_RSP);
msg.putHeader(getName(), hdr);
passDown(new Event(Event.MSG, msg));
}
/// <summary>
/// Deals with incoming join requests. If we are a coordinator then a response will be sent.
/// </summary>
/// <param name="mbr"></param>
void handleJoinRequest(Address mbr)
{
JoinRsp join_rsp;
Message m;
GmsHeader hdr;
ArrayList new_mbrs = new ArrayList();
if (mbr == null)
{
if (Trace.trace)
{
Trace.error("GMS.handleJoinRequest()", "mbr is null");
}
return;
}
if (Trace.trace)
{
Trace.info("GMS.handleJoinRequest()", "mbr=" + mbr);
}
// 1. Get the new view and digest
join_rsp = impl.handleJoin(mbr);
if (join_rsp == null)
{
if (Trace.trace)
{
Trace.error("GMS.handleJoinRequest()", impl.getName() + ".handleJoin(" + mbr +
") returned null: will not be able to multicast new view");
}
}
// 2. Send down a local TMP_VIEW event. This is needed by certain layers (e.g. NAKACK) to compute correct digest
// in case client's next request reaches us *before* our own view change multicast.
if (join_rsp != null && join_rsp.getView() != null)
{
passDown(new Event(Event.TMP_VIEW, join_rsp.getView()));
}
// 3. Return result to client
m = new Message(mbr, null, null);
hdr = new GmsHeader(GmsHeader.JOIN_RSP, join_rsp);
m.putHeader(getName(), hdr);
passDown(new Event(Event.MSG, m));
// 4. Bcast the new view
if (join_rsp != null)
{
castViewChange(join_rsp.getView());
}
}
/// <summary>
/// Multicasts a new view.
/// </summary>
/// <param name="new_view">New View to send</param>
/// <param name="digest">Digest associated with View</param>
public void castViewChange(View new_view, Digest digest)
{
Message view_change_msg;
GmsHeader hdr;
if (Trace.trace)
{
Trace.info("GMS.castViewChange()", "mcasting view {" + new_view + "} (" + new_view.size() + " mbrs)\n");
}
view_change_msg = new Message(null, null, null); // bcast to all members
hdr = new GmsHeader(GmsHeader.VIEW, new_view);
hdr.digest = digest;
view_change_msg.putHeader(getName(), hdr);
passDown(new Event(Event.MSG, view_change_msg));
}
/// <summary>
/// Acknowledges leave response.
/// </summary>
/// <param name="mbr"></param>
private void sendLeaveResponse(Address mbr)
{
Message msg=new Message(mbr, null, null);
GmsHeader hdr=new GmsHeader(GmsHeader.LEAVE_RSP);
msg.putHeader(getName(), hdr);
passDown(new Event(Event.MSG, msg));
}
/// <summary>
/// Deals with incoming join requests. If we are a coordinator then a response will be sent.
/// </summary>
/// <param name="mbr"></param>
void handleJoinRequest(Address mbr)
{
JoinRsp join_rsp;
Message m;
GmsHeader hdr;
ArrayList new_mbrs=new ArrayList();
if(mbr == null)
{
if(Trace.trace)
Trace.error("GMS.handleJoinRequest()", "mbr is null");
return;
}
if(Trace.trace)
Trace.info("GMS.handleJoinRequest()", "mbr=" + mbr);
// 1. Get the new view and digest
join_rsp=impl.handleJoin(mbr);
if(join_rsp == null)
if(Trace.trace)
Trace.error("GMS.handleJoinRequest()", impl.getName() + ".handleJoin(" + mbr +
") returned null: will not be able to multicast new view");
// 2. Send down a local TMP_VIEW event. This is needed by certain layers (e.g. NAKACK) to compute correct digest
// in case client's next request reaches us *before* our own view change multicast.
if(join_rsp != null && join_rsp.getView() != null)
passDown(new Event(Event.TMP_VIEW, join_rsp.getView()));
// 3. Return result to client
m=new Message(mbr, null, null);
hdr=new GmsHeader(GmsHeader.JOIN_RSP, join_rsp);
m.putHeader(getName(), hdr);
passDown(new Event(Event.MSG, m));
// 4. Bcast the new view
if(join_rsp != null)
castViewChange(join_rsp.getView());
}
/// <summary>
/// Multicasts a new view.
/// </summary>
/// <param name="new_view">New View to send</param>
/// <param name="digest">Digest associated with View</param>
public void castViewChange(View new_view, Digest digest)
{
Message view_change_msg;
GmsHeader hdr;
if(Trace.trace)
Trace.info("GMS.castViewChange()", "mcasting view {" + new_view + "} (" + new_view.size() + " mbrs)\n");
view_change_msg=new Message(null,null,null); // bcast to all members
hdr=new GmsHeader(GmsHeader.VIEW, new_view);
hdr.digest=digest;
view_change_msg.putHeader(getName(), hdr);
passDown(new Event(Event.MSG, view_change_msg));
}
/// <summary>
/// Sends a join message to the coordinator of the group.
/// </summary>
/// <param name="coord">The Address of the Coordinator</param>
/// <param name="mbr">The local Address (i.e. this member)</param>
private void sendJoinMessage(Address coord, Address mbr)
{
Message msg;
GmsHeader hdr;
msg=new Message(coord, null, null);
hdr=new GmsHeader(GmsHeader.JOIN_REQ, mbr);
msg.putHeader(gms.getName(), hdr);
gms.passDown(new Event(Event.MSG, msg));
}
/// <summary>
/// Processes <c>Events</c> travelling up the stack
/// </summary>
/// <param name="evt">The Event to be processed</param>
public override void up(Event evt)
{
Object obj;
Message msg;
GmsHeader hdr;
switch (evt.Type)
{
case Event.MSG:
msg = (Message)evt.Arg;
obj = msg.getHeader(getName());
if (obj == null || !(obj is GmsHeader))
{
break;
}
hdr = (GmsHeader)msg.removeHeader(getName());
if (Trace.trace)
{
Trace.info("GMS.up()", "Receieved Event " + GmsHeader.type2String(hdr.type));
}
if (hdr.type == GmsHeader.JOIN_REQ)
{
handleJoinRequest(hdr.mbr);
break;
}
else if (hdr.type == GmsHeader.JOIN_RSP)
{
impl.handleJoinResponse(hdr.join_rsp);
break;
}
else if (hdr.type == GmsHeader.LEAVE_REQ)
{
if (Trace.trace)
{
Trace.info("GMS.up()", "received LEAVE_REQ " + hdr + " from " + msg.Source);
}
if (hdr.mbr == null)
{
if (Trace.trace)
{
Trace.error("GMS.up()", "LEAVE_REQ's mbr field is null");
}
return;
}
sendLeaveResponse(hdr.mbr);
impl.handleLeave(hdr.mbr, false);
break;
}
else if (hdr.type == GmsHeader.LEAVE_RSP)
{
impl.handleLeaveResponse();
break;
}
else if (hdr.type == GmsHeader.VIEW)
{
if (hdr.view == null)
{
if (Trace.trace)
{
Trace.error("GMS.up()", "[VIEW]: view == null");
}
return;
}
impl.handleViewChange(hdr.view, hdr.digest);
break;
}
else
{
if (Trace.trace)
{
Trace.error("GMS.up()", "GmsHeader with type=" + hdr.type + " not known");
}
return; // don't pass up
}
case Event.CONNECT_OK: // sent by someone else, but WE are responsible for sending this !
case Event.DISCONNECT_OK: // dito (e.g. sent by UDP layer). Don't send up the stack
return;
case Event.SET_LOCAL_ADDRESS:
local_addr = (Address)evt.Arg;
if (print_local_addr)
{
Console.WriteLine("\n-------------------------------------------------------\n" +
"GMS: address is " + local_addr +
"\n-------------------------------------------------------");
}
break; // pass up
case Event.SUSPECT:
impl.suspect((Address)evt.Arg);
break; // pass up
case Event.UNSUSPECT:
impl.unsuspect((Address)evt.Arg);
return; // discard
}
if (impl.handleUpEvent(evt))
{
passUp(evt);
}
}