public Set get()

in software/nosql/src/main/java/org/apache/brooklyn/entity/nosql/cassandra/CassandraDatacenterImpl.java [97:131]
32 lines of code
9 McCabe index (conditional complexity)

        public Set<Entity> get() {
            synchronized (seedMutex) {
                boolean hasPublishedSeeds = Boolean.TRUE.equals(getAttribute(HAS_PUBLISHED_SEEDS));
                int quorumSize = getSeedQuorumSize();
                Set<Entity> potentialSeeds = gatherPotentialSeeds();
                Set<Entity> potentialRunningSeeds = gatherPotentialRunningSeeds();
                boolean stillWaitingForQuorum = (!hasPublishedSeeds) && (potentialSeeds.size() < quorumSize);
                
                if (stillWaitingForQuorum) {
                    if (log.isDebugEnabled()) log.debug("Not refreshed seeds of cluster {}, because still waiting for quorum (need {}; have {} potentials)", new Object[] {CassandraDatacenterImpl.class, quorumSize, potentialSeeds.size()});
                    return ImmutableSet.of();
                } else if (hasPublishedSeeds) {
                    Set<Entity> currentSeeds = getAttribute(CURRENT_SEEDS);
                    if (getAttribute(SERVICE_STATE_ACTUAL) == Lifecycle.STARTING) {
                        if (Sets.intersection(currentSeeds, potentialSeeds).isEmpty()) {
                            log.warn("Cluster {} lost all its seeds while starting! Subsequent failure likely, but changing seeds during startup would risk split-brain: seeds={}", new Object[] {CassandraDatacenterImpl.this, currentSeeds});
                        }
                        return currentSeeds;
                    } else if (potentialRunningSeeds.isEmpty()) {
                        // TODO Could be race where nodes have only just returned from start() and are about to 
                        // transition to serviceUp; so don't just abandon all our seeds!
                        log.warn("Cluster {} has no running seeds (yet?); leaving seeds as-is; but risks split-brain if these seeds come back up!", new Object[] {CassandraDatacenterImpl.this});
                        return currentSeeds;
                    } else {
                        Set<Entity> result = trim(quorumSize, potentialRunningSeeds);
                        log.debug("Cluster {} updating seeds: chosen={}; potentialRunning={}", new Object[] {CassandraDatacenterImpl.this, result, potentialRunningSeeds});
                        return result;
                    }
                } else {
                    Set<Entity> result = trim(quorumSize, potentialSeeds);
                    if (log.isDebugEnabled()) log.debug("Cluster {} has reached seed quorum: seeds={}", new Object[] {CassandraDatacenterImpl.this, result});
                    return result;
                }
            }
        }