/// <summary>
/// Computes the next view, removes old and suspected members, adds new members.
/// </summary>
/// <param name="new_mbrs">New members to be added to the view</param>
/// <param name="old_mbrs">Old members to be removed from the view</param>
/// <param name="suspected_mbrs">Suspected members to be removed from the view</param>
/// <returns>The new View</returns>
public View getNextView(ArrayList new_mbrs, ArrayList old_mbrs, ArrayList suspected_mbrs)
{
ArrayList mbrs;
long vid = 0;
View v;
Membership tmp_mbrs = null;
Address tmp_mbr;
lock (members)
{
if (view_id == null)
{
return(null); // this should *never* happen !
}
vid = Math.Max(view_id.getId(), ltime) + 1;
ltime = vid;
if (Trace.trace)
{
Trace.info("GMS.getNextView()", "VID=" + vid + ", current members=" +
printMembers(members.getMembers()) +
", new_mbrs=" + printMembers(new_mbrs) +
", old_mbrs=" + printMembers(old_mbrs) + ", suspected_mbrs=" +
printMembers(suspected_mbrs));
}
tmp_mbrs = tmp_members.copy(); // always operate on the temporary membership
tmp_mbrs.remove(suspected_mbrs);
tmp_mbrs.remove(old_mbrs);
tmp_mbrs.add(new_mbrs);
mbrs = (ArrayList)tmp_mbrs.getMembers();
v = new View(local_addr, vid, mbrs);
// Update membership
tmp_members.set(mbrs);
// Update joining list
if (new_mbrs != null)
{
for (int i = 0; i < new_mbrs.Count; i++)
{
tmp_mbr = (Address)new_mbrs[i];
if (!joining.Contains(tmp_mbr))
{
joining.Add(tmp_mbr);
}
}
}
if (Trace.trace)
{
Trace.info("GMS.getNextView()", "new view is " + v);
}
return(v);
}
}
/// <summary>
/// Sets the new view and sends a VIEW_CHANGE event up and down the stack.
/// </summary>
/// <param name="new_view">New View to install</param>
public void installView(View new_view)
{
Address coord;
int rc;
ViewId vid = new_view.getVid();
ArrayList mbrs = new_view.getMembers();
lock (members)
{ // serialize access to views
ltime = Math.Max(vid.getId(), ltime); // compute Lamport logical time
/* Check for self-inclusion: if I'm not part of the new membership, I just discard it.
* This ensures that messages sent in view V1 are only received by members of V1 */
if (Trace.trace)
{
Trace.info("GMS.installView()", "View to install contains: " + new_view.ToString());
}
if (checkSelfInclusion(mbrs) == false)
{
if (Trace.trace)
{
Trace.warn("GMS.installView()",
"checkSelfInclusion() failed, not a member of view " + mbrs + "; discarding view");
}
if (shun)
{
if (Trace.trace)
{
Trace.warn("GMS.installView()", "I'm being shunned, will leave and rejoin group");
}
passUp(new Event(Event.EXIT));
}
return;
}
// Discards view with id lower than our own. Will be installed without check if first view
if (view_id != null)
{
rc = vid.CompareTo(view_id);
if (rc <= 0)
{
if (Trace.trace)
{
Trace.error("GMS.installView()", "received view <= current view;" +
" discarding it ! (current vid: " + view_id + ", new vid: " + vid + ")");
}
return;
}
}
if (Trace.trace)
{
Trace.info("GMS.installView()", "view is " + new_view);
}
// assign new_view to view_id
view_id = vid.Copy();
// Set the membership. Take into account joining members
if (mbrs != null && mbrs.Count > 0)
{
members.set(mbrs);
tmp_members.set(members);
foreach (Object obj in mbrs)
{
joining.Remove(obj); // remove all members in mbrs from joining
}
tmp_members.add(joining); // adjust temporary membership
}
// Send VIEW_CHANGE event up and down the stack:
Event view_event = new Event(Event.VIEW_CHANGE, (View)new_view.copy());
passDown(view_event); // needed e.g. by failure detector or UDP
passUp(view_event);
coord = determineCoordinator();
if (coord != null && coord.Equals(local_addr) && !(coord.Equals(vid.getCoordAddress())))
{
becomeCoordinator();
}
else
{
if (haveCoordinatorRole() && !local_addr.Equals(coord))
{
becomeParticipant();
}
}
}
}