GOSSIP-49 Refactor Failure detector Lambda into named class

src/main/java/org/apache/gossip/manager/GossipManager.java

@@ -19,9 +19,9 @@ package org.apache.gossip.manager;
 
 import com.codahale.metrics.MetricRegistry;
 import com.fasterxml.jackson.databind.ObjectMapper;
-import org.apache.gossip.Member;
 import org.apache.gossip.GossipSettings;
 import org.apache.gossip.LocalMember;
+import org.apache.gossip.Member;
 import org.apache.gossip.crdt.Crdt;
 import org.apache.gossip.event.GossipListener;
 import org.apache.gossip.event.GossipState;
@@ -29,7 +29,6 @@ import org.apache.gossip.manager.handlers.MessageInvoker;
 import org.apache.gossip.manager.impl.OnlyProcessReceivedPassiveGossipThread;
 import org.apache.gossip.model.PerNodeDataMessage;
 import org.apache.gossip.model.SharedDataMessage;
-import org.apache.gossip.model.ShutdownMessage;
 import org.apache.log4j.Logger;
 
 import java.lang.reflect.Constructor;
@@ -63,6 +62,7 @@ public abstract class GossipManager {
   private final MetricRegistry registry;
   private final RingStatePersister ringState;
   private final UserDataPersister userDataState;
+  private final GossipMemberStateRefresher memberStateRefresher;
   private final ObjectMapper objectMapper;
 
   private final MessageInvoker messageInvoker;
@@ -73,6 +73,7 @@ public abstract class GossipManager {
                        ObjectMapper objectMapper, MessageInvoker messageInvoker) {
     this.settings = settings;
     this.messageInvoker = messageInvoker;
+
     clock = new SystemClock();
     me = new LocalMember(cluster, uri, id, clock.nanoTime(), properties,
             settings.getWindowSize(), settings.getMinimumSamples(), settings.getDistribution());
@@ -96,6 +97,7 @@ public abstract class GossipManager {
     this.registry = registry;
     this.ringState = new RingStatePersister(this);
     this.userDataState = new UserDataPersister(this, this.gossipCore);
+    this.memberStateRefresher = new GossipMemberStateRefresher(members, settings, listener, this::findPerNodeGossipData);
     this.objectMapper = objectMapper;
     readSavedRingState();
     readSavedDataState();
@@ -161,67 +163,10 @@ public abstract class GossipManager {
     dataReaper.init();
     scheduledServiced.scheduleAtFixedRate(ringState, 60, 60, TimeUnit.SECONDS);
     scheduledServiced.scheduleAtFixedRate(userDataState, 60, 60, TimeUnit.SECONDS);
-    scheduledServiced.scheduleAtFixedRate(() -> {
+    scheduledServiced.scheduleAtFixedRate(memberStateRefresher, 0, 100, TimeUnit.MILLISECONDS);
-      try {
-        for (Entry<LocalMember, GossipState> entry : members.entrySet()) {
-          boolean userDown = processOptomisticShutdown(entry);
-          if (userDown)
-            continue;
-          Double result = null;
-          try {
-            result = entry.getKey().detect(clock.nanoTime());
-            if (result != null) {
-              if (result > settings.getConvictThreshold() && entry.getValue() == GossipState.UP) {
-                members.put(entry.getKey(), GossipState.DOWN);
-                listener.gossipEvent(entry.getKey(), GossipState.DOWN);
-              }
-              if (result <= settings.getConvictThreshold() && entry.getValue() == GossipState.DOWN) {
-                members.put(entry.getKey(), GossipState.UP);
-                listener.gossipEvent(entry.getKey(), GossipState.UP);
-              }
-            }
-          } catch (IllegalArgumentException ex) {
-            //0.0 returns throws exception computing the mean. 
-            long now = clock.nanoTime(); 
-            long nowInMillis = TimeUnit.MILLISECONDS.convert(now,TimeUnit.NANOSECONDS);
-            if (nowInMillis - settings.getCleanupInterval() > entry.getKey().getHeartbeat() && entry.getValue() == GossipState.UP){
-              LOGGER.warn("Marking down");
-              members.put(entry.getKey(), GossipState.DOWN);
-              listener.gossipEvent(entry.getKey(), GossipState.DOWN);
-            }
-          } //end catch
-        } // end for
-      } catch (RuntimeException ex) {
-        LOGGER.warn("scheduled state had exception", ex);
-      }
-    }, 0, 100, TimeUnit.MILLISECONDS);
     LOGGER.debug("The GossipManager is started.");
   }
 
-  /**
-   * If we have a special key the per-node data that means that the node has sent us 
-   * a pre-emptive shutdown message. We process this so node is seen down sooner
-   * @param l member to consider
-   * @return true if node forced down
-   */
-  public boolean processOptomisticShutdown(Entry<LocalMember, GossipState> l){
-    PerNodeDataMessage m = findPerNodeGossipData(l.getKey().getId(), ShutdownMessage.PER_NODE_KEY);
-    if (m == null){
-      return false;
-    }
-    ShutdownMessage s = (ShutdownMessage) m.getPayload();
-    if (s.getShutdownAtNanos() > l.getKey().getHeartbeat()){
-      if (l.getValue() == GossipState.UP){
-        members.put(l.getKey(), GossipState.DOWN);
-        listener.gossipEvent(l.getKey(), GossipState.DOWN);
-      } else {
-        members.put(l.getKey(), GossipState.DOWN);
-      }
-      return true;
-    }
-    return false;
-  }
-  
   private void readSavedRingState() {
     for (LocalMember l : ringState.readFromDisk()){
       LocalMember member = new LocalMember(l.getClusterName(),
@@ -357,6 +302,10 @@ public abstract class GossipManager {
     return userDataState;
   }
 
+  public GossipMemberStateRefresher getMemberStateRefresher() {
+    return memberStateRefresher;
+  }
+
   public Clock getClock() {
     return clock;
   }

src/main/java/org/apache/gossip/manager/GossipMemberStateRefresher.java

@@ -0,0 +1,117 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you 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.
+ */
+
+package org.apache.gossip.manager;
+
+import org.apache.gossip.GossipSettings;
+import org.apache.gossip.LocalMember;
+import org.apache.gossip.event.GossipListener;
+import org.apache.gossip.event.GossipState;
+import org.apache.gossip.model.PerNodeDataMessage;
+import org.apache.gossip.model.ShutdownMessage;
+import org.apache.log4j.Logger;
+
+import java.util.Map;
+import java.util.Map.Entry;
+import java.util.concurrent.TimeUnit;
+import java.util.function.BiFunction;
+
+public class GossipMemberStateRefresher implements Runnable {
+  public static final Logger LOGGER = Logger.getLogger(GossipMemberStateRefresher.class);
+
+  private final Map<LocalMember, GossipState> members;
+  private final GossipSettings settings;
+  private final GossipListener listener;
+  private final Clock clock;
+  private final BiFunction<String, String, PerNodeDataMessage> findPerNodeGossipData;
+
+  public GossipMemberStateRefresher(Map<LocalMember, GossipState> members, GossipSettings settings,
+                                    GossipListener listener, BiFunction<String, String, PerNodeDataMessage> findPerNodeGossipData) {
+    this.members = members;
+    this.settings = settings;
+    this.listener = listener;
+    this.findPerNodeGossipData = findPerNodeGossipData;
+    clock = new SystemClock();
+  }
+
+  public void run() {
+    try {
+      runOnce();
+    } catch (RuntimeException ex) {
+      LOGGER.warn("scheduled state had exception", ex);
+    }
+  }
+
+  public void runOnce() {
+    for (Entry<LocalMember, GossipState> entry : members.entrySet()) {
+      boolean userDown = processOptimisticShutdown(entry);
+      if (userDown)
+        continue;
+      try {
+        Double phiMeasure = entry.getKey().detect(clock.nanoTime());
+        if (phiMeasure != null) {
+          GossipState requiredState = calcRequiredState(phiMeasure);
+          if (entry.getValue() != requiredState) {
+            members.put(entry.getKey(), requiredState);
+            listener.gossipEvent(entry.getKey(), requiredState);
+          }
+        }
+      } catch (IllegalArgumentException ex) {
+        //0.0 returns throws exception computing the mean.
+
+        long now = clock.nanoTime();
+        long nowInMillis = TimeUnit.MILLISECONDS.convert(now, TimeUnit.NANOSECONDS);
+        if (nowInMillis - settings.getCleanupInterval() > entry.getKey().getHeartbeat() && entry.getValue() == GossipState.UP) {
+          LOGGER.warn("Marking down");
+          members.put(entry.getKey(), GossipState.DOWN);
+          listener.gossipEvent(entry.getKey(), GossipState.DOWN);
+        }
+      } //end catch
+    } // end for
+  }
+
+  public GossipState calcRequiredState(Double phiMeasure) {
+    if (phiMeasure > settings.getConvictThreshold())
+      return GossipState.DOWN;
+    else
+      return GossipState.UP;
+  }
+
+  /**
+   * If we have a special key the per-node data that means that the node has sent us
+   * a pre-emptive shutdown message. We process this so node is seen down sooner
+   *
+   * @param l member to consider
+   * @return true if node forced down
+   */
+  public boolean processOptimisticShutdown(Entry<LocalMember, GossipState> l) {
+    PerNodeDataMessage m = findPerNodeGossipData.apply(l.getKey().getId(), ShutdownMessage.PER_NODE_KEY);
+    if (m == null) {
+      return false;
+    }
+    ShutdownMessage s = (ShutdownMessage) m.getPayload();
+    if (s.getShutdownAtNanos() > l.getKey().getHeartbeat()) {
+      members.put(l.getKey(), GossipState.DOWN);
+      if (l.getValue() == GossipState.UP) {
+        listener.gossipEvent(l.getKey(), GossipState.DOWN);
+      }
+      return true;
+    }
+    return false;
+  }
+}

src/main/java/org/apache/gossip/manager/PassiveGossipThread.java

@@ -85,6 +85,7 @@ abstract public class PassiveGossipThread implements Runnable {
             gossipCore.receive(activeGossipMessage);
             unsigned.mark();
           }
+          gossipManager.getMemberStateRefresher().run();
         } catch (RuntimeException ex) {//TODO trap json exception
           LOGGER.error("Unable to process message", ex);
         }

src/main/java/org/apache/gossip/manager/handlers/MessageInvokerCombiner.java

@@ -24,6 +24,7 @@ import org.apache.gossip.model.Base;
 
 import java.util.List;
 import java.util.concurrent.CopyOnWriteArrayList;
+import java.util.function.Predicate;
 
 public class MessageInvokerCombiner implements MessageInvoker {
   private final List<MessageInvoker> invokers = new CopyOnWriteArrayList<>();
@@ -32,14 +33,7 @@ public class MessageInvokerCombiner implements MessageInvoker {
   }
 
   public boolean invoke(GossipCore gossipCore, GossipManager gossipManager, Base base) {
-    if (invokers == null) {
+    return invokers.stream().filter((mi) -> mi.invoke(gossipCore, gossipManager, base)).count() > 0;
-      return false;
-    }
-    boolean result = false;
-    for (MessageInvoker mi : invokers) {
-      result = mi.invoke(gossipCore, gossipManager, base) || result;
-    }
-    return result;
   }
 
   public void clear() {

src/test/java/org/apache/gossip/ShutdownDeadtimeTest.java

@@ -81,6 +81,7 @@ public class ShutdownDeadtimeTest {
         return total;
       }
     }).afterWaitingAtMost(40, TimeUnit.SECONDS).isEqualTo(20);
+
     // shutdown one client and verify that one client is lost.
     Random r = new Random();
     int randomClientId = r.nextInt(clusterMembers);