/**
* Invoked upon receiving a MERGE event from the MERGE layer. Starts the merge protocol. See
* description of protocol in DESIGN.
*
* @param views A List of <em>different</em> views detected by the merge protocol
*/
public void merge(Map<Address, View> views) {
if (isMergeInProgress()) {
if (log.isTraceEnabled())
log.trace(gms.local_addr + ": merge is already running (merge_id=" + merge_id + ")");
return;
}
// we need the merge *coordinators* not merge participants because not everyone can lead a merge
// !
Collection<Address> coords = Util.determineActualMergeCoords(views);
if (coords.isEmpty()) {
log.error(
gms.local_addr
+ ": unable to determine merge leader from "
+ views
+ "; not starting a merge");
return;
}
Membership tmp =
new Membership(coords); // establish a deterministic order, so that coords can elect leader
tmp.sort();
Address merge_leader = tmp.elementAt(0);
if (merge_leader.equals(gms.local_addr)) {
if (log.isDebugEnabled()) {
Collection<Address> merge_participants = Util.determineMergeParticipants(views);
log.debug(
"I ("
+ gms.local_addr
+ ") will be the leader. Starting the merge task for "
+ merge_participants.size()
+ " coords");
}
merge_task.start(views);
} else {
if (log.isTraceEnabled())
log.trace(
"I ("
+ gms.local_addr
+ ") am not the merge leader, "
+ "waiting for merge leader ("
+ merge_leader
+ ") to initiate merge");
}
}
