diff options
Diffstat (limited to 'feature-pooling-dmaap/src/main/java/org/onap/policy/drools/pooling/state/ActiveState.java')
-rw-r--r-- | feature-pooling-dmaap/src/main/java/org/onap/policy/drools/pooling/state/ActiveState.java | 255 |
1 files changed, 255 insertions, 0 deletions
diff --git a/feature-pooling-dmaap/src/main/java/org/onap/policy/drools/pooling/state/ActiveState.java b/feature-pooling-dmaap/src/main/java/org/onap/policy/drools/pooling/state/ActiveState.java new file mode 100644 index 00000000..5f503a3b --- /dev/null +++ b/feature-pooling-dmaap/src/main/java/org/onap/policy/drools/pooling/state/ActiveState.java @@ -0,0 +1,255 @@ +/* + * ============LICENSE_START======================================================= + * ONAP + * ================================================================================ + * Copyright (C) 2018 AT&T Intellectual Property. All rights reserved. + * ================================================================================ + * Licensed under the Apache License, Version 2.0 (the "License"); + * you may not use this file except in compliance with the License. + * You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + * ============LICENSE_END========================================================= + */ + +package org.onap.policy.drools.pooling.state; + +import java.util.Arrays; +import java.util.TreeSet; +import org.onap.policy.drools.pooling.PoolingManager; +import org.onap.policy.drools.pooling.message.Heartbeat; +import org.onap.policy.drools.pooling.message.Offline; +import org.onap.policy.drools.pooling.message.Query; + +/** + * The active state. In this state, this host has one more more bucket + * assignments and processes any events associated with one of its buckets. + * Other events are forwarded to appropriate target hosts. + */ +public class ActiveState extends ProcessingState { + + /** + * Set of hosts that have been assigned a bucket. + */ + private final TreeSet<String> assigned = new TreeSet<>(); + + /** + * Host that comes after this host, or {@code null} if it has no successor. + */ + private String succHost = null; + + /** + * Host that comes before this host, or "" if it has no predecessor. + */ + private String predHost = ""; + + /** + * {@code True} if we saw this host's heart beat since the last check, + * {@code false} otherwise. + */ + private boolean myHeartbeatSeen = false; + + /** + * {@code True} if we saw the predecessor's heart beat since the last check, + * {@code false} otherwise. + */ + private boolean predHeartbeatSeen = false; + + /** + * + * @param mgr + */ + public ActiveState(PoolingManager mgr) { + super(mgr, mgr.getAssignments().getLeader()); + + assigned.addAll(Arrays.asList(mgr.getAssignments().getHostArray())); + + detmNeighbors(); + } + + /** + * Determine this host's neighbors based on the order of the host UUIDs. + * Updates {@link #succHost} and {@link #predHost}. + */ + private void detmNeighbors() { + if (assigned.size() < 2) { + /* + * this host is the only one with any assignments - it has no + * neighbors + */ + succHost = null; + predHost = ""; + return; + } + + if ((succHost = assigned.higher(getHost())) == null) { + // wrapped around - successor is the first host in the set + succHost = assigned.first(); + } + + if ((predHost = assigned.lower(getHost())) == null) { + // wrapped around - predecessor is the last host in the set + predHost = assigned.last(); + } + } + + @Override + public void start() { + addTimers(); + genHeartbeat(); + } + + /** + * Adds the timers. + */ + private void addTimers() { + + /* + * heart beat generator + */ + long genMs = getProperties().getActiveHeartbeatMs(); + + scheduleWithFixedDelay(genMs, genMs, xxx -> { + genHeartbeat(); + return null; + }); + + /* + * my heart beat checker + */ + long interMs = getProperties().getInterHeartbeatMs(); + + scheduleWithFixedDelay(interMs, interMs, xxx -> { + if (myHeartbeatSeen) { + myHeartbeatSeen = false; + return null; + } + + // missed my heart beat + + return internalTopicFailed(); + }); + + /* + * predecessor heart beat checker + */ + if (!predHost.isEmpty()) { + + scheduleWithFixedDelay(interMs, interMs, xxx -> { + if (predHeartbeatSeen) { + predHeartbeatSeen = false; + return null; + } + + // missed the predecessor's heart beat + publish(makeQuery()); + + return goQuery(); + }); + } + } + + /** + * Generates a heart beat for this host and its successor. + */ + private void genHeartbeat() { + Heartbeat msg = makeHeartbeat(System.currentTimeMillis()); + publish(getHost(), msg); + + if (succHost != null) { + publish(succHost, msg); + } + } + + @Override + public State process(Heartbeat msg) { + String src = msg.getSource(); + + if (src == null) { + return null; + + } else if (src.equals(getHost())) { + myHeartbeatSeen = true; + + } else if (src.equals(predHost)) { + predHeartbeatSeen = true; + + } + + return null; + } + + @Override + public State process(Offline msg) { + String src = msg.getSource(); + + if (src == null) { + return null; + + } else if (!assigned.contains(src)) { + /* + * the offline host wasn't assigned any buckets, so just ignore the + * message + */ + return null; + + } else if (isLeader() || (predHost.equals(src) && predHost.equals(assigned.first()))) { + /* + * Case 1: We are the leader. + * + * Case 2: Our predecessor was the leader and it has gone offline - + * we should become the leader. + * + * In either case, we are now the leader and we must re-balance the + * buckets since one of the hosts has gone offline. + */ + + assigned.remove(src); + + return becomeLeader(assigned); + + } else { + /* + * Otherwise, we don't care right now - we'll wait for the leader to + * tell us it's been removed. + */ + return null; + } + } + + /** + * Transitions to the query state. + */ + @Override + public State process(Query msg) { + State next = super.process(msg); + if (next != null) { + return next; + } + + return goQuery(); + } + + protected String getSuccHost() { + return succHost; + } + + protected String getPredHost() { + return predHost; + } + + protected boolean isMyHeartbeatSeen() { + return myHeartbeatSeen; + } + + protected boolean isPredHeartbeatSeen() { + return predHeartbeatSeen; + } + +} |