Callback

src/main/java/com/google/code/gossip/GossipService.java

@@ -6,6 +6,7 @@ import java.net.UnknownHostException;
 import java.util.ArrayList;
 import org.apache.log4j.Logger;
 
+import com.google.code.gossip.event.GossipListener;
 import com.google.code.gossip.manager.GossipManager;
 import com.google.code.gossip.manager.random.RandomGossipManager;
 
@@ -30,7 +31,7 @@ public class GossipService {
           UnknownHostException {
     this(InetAddress.getLocalHost().getHostAddress(), startupSettings.getPort(), "",
             startupSettings.getLogLevel(), startupSettings.getGossipMembers(), startupSettings
-                    .getGossipSettings());
+                    .getGossipSettings(), null);
   }
 
   /**
@@ -41,9 +42,9 @@ public class GossipService {
    * @throws UnknownHostException
    */
   public GossipService(String ipAddress, int port, String id, int logLevel,
-          ArrayList<GossipMember> gossipMembers, GossipSettings settings)
+          ArrayList<GossipMember> gossipMembers, GossipSettings settings, GossipListener listener)
           throws InterruptedException, UnknownHostException {
-    _gossipManager = new RandomGossipManager(ipAddress, port, id, settings, gossipMembers);
+    _gossipManager = new RandomGossipManager(ipAddress, port, id, settings, gossipMembers, listener);
   }
 
   public void start() {

src/main/java/com/google/code/gossip/event/GossipListener.java

@@ -0,0 +1,7 @@
+package com.google.code.gossip.event;
+
+import com.google.code.gossip.GossipMember;
+
+public interface GossipListener {
+  void gossipEvent(GossipMember member, GossipState state);
+}

src/main/java/com/google/code/gossip/event/GossipState.java

@@ -0,0 +1,10 @@
+package com.google.code.gossip.event;
+
+public enum GossipState {
+  UP("up"), DOWN("down");
+  private String state;
+  
+  private GossipState(String state){
+    this.state = state;
+  }
+}

src/main/java/com/google/code/gossip/examples/GossipExample.java

@@ -58,7 +58,7 @@ public class GossipExample extends Thread {
       // dead list handling.
       for (GossipMember member : startupMembers) {
         GossipService gossipService = new GossipService(myIpAddress, member.getPort(), "",
-                LogLevel.DEBUG, startupMembers, settings);
+                LogLevel.DEBUG, startupMembers, settings, null);
         clients.add(gossipService);
         gossipService.start();
         sleep(settings.getCleanupInterval() + 1000);

src/main/java/com/google/code/gossip/manager/ActiveGossipThread.java

@@ -1,6 +1,5 @@
 package com.google.code.gossip.manager;
 
-import java.util.ArrayList;
 import java.util.List;
 import java.util.concurrent.TimeUnit;
 import java.util.concurrent.atomic.AtomicBoolean;

src/main/java/com/google/code/gossip/manager/GossipManager.java

@@ -20,13 +20,15 @@ import com.google.code.gossip.GossipMember;
 import com.google.code.gossip.GossipService;
 import com.google.code.gossip.GossipSettings;
 import com.google.code.gossip.LocalGossipMember;
+import com.google.code.gossip.event.GossipListener;
+import com.google.code.gossip.event.GossipState;
 
 public abstract class GossipManager extends Thread implements NotificationListener {
   
   public static final Logger LOGGER = Logger.getLogger(GossipManager.class);
   public static final int MAX_PACKET_SIZE = 102400;
 
-  private ConcurrentSkipListMap<LocalGossipMember,String> members;
+  private ConcurrentSkipListMap<LocalGossipMember,GossipState> members;
   private LocalGossipMember _me;
   private GossipSettings _settings;
   private AtomicBoolean _gossipServiceRunning;
@@ -35,10 +37,12 @@ public abstract class GossipManager extends Thread implements NotificationListen
   private PassiveGossipThread passiveGossipThread;
   private Class<? extends ActiveGossipThread> _activeGossipThreadClass;
   private ActiveGossipThread activeGossipThread;
+  private GossipListener listener;
 
   public GossipManager(Class<? extends PassiveGossipThread> passiveGossipThreadClass,
           Class<? extends ActiveGossipThread> activeGossipThreadClass, String address, int port,
-          String id, GossipSettings settings, ArrayList<GossipMember> gossipMembers) {
+          String id, GossipSettings settings, ArrayList<GossipMember> gossipMembers, 
+          GossipListener listener) {
     _passiveGossipThreadClass = passiveGossipThreadClass;
     _activeGossipThreadClass = activeGossipThreadClass;
     _settings = settings;
@@ -49,12 +53,13 @@ public abstract class GossipManager extends Thread implements NotificationListen
         LocalGossipMember member = new LocalGossipMember(startupMember.getHost(),
                 startupMember.getPort(), startupMember.getId(), 0, this,
                 settings.getCleanupInterval());
-        members.put(member, "UP");
+        members.put(member, GossipState.UP);
         GossipService.LOGGER.debug(member);
       }
     }
 
     _gossipServiceRunning = new AtomicBoolean(true);
+    this.listener = listener;
     Runtime.getRuntime().addShutdownHook(new Thread(new Runnable() {
       public void run() {
         GossipService.LOGGER.info("Service has been shutdown...");
@@ -70,7 +75,17 @@ public abstract class GossipManager extends Thread implements NotificationListen
   public void handleNotification(Notification notification, Object handback) {
     LocalGossipMember deadMember = (LocalGossipMember) notification.getUserData();
     GossipService.LOGGER.info("Dead member detected: " + deadMember);
-    members.put(deadMember, "DOWN");
+    members.put(deadMember, GossipState.DOWN);
+    if (listener != null) {
+      listener.gossipEvent(deadMember, GossipState.DOWN);
+    }
+  }
+
+  public void createOrRevivieMember(LocalGossipMember m){
+    members.put(m, GossipState.UP);
+    if (listener != null) {
+      listener.gossipEvent(m, GossipState.UP);
+    }
   }
   
   public GossipSettings getSettings() {
@@ -79,8 +94,8 @@ public abstract class GossipManager extends Thread implements NotificationListen
 
   public List<LocalGossipMember> getMemberList() {
     List<LocalGossipMember> up = new ArrayList<>();
-    for (Entry<LocalGossipMember, String> entry : members.entrySet()){
+    for (Entry<LocalGossipMember, GossipState> entry : members.entrySet()){
-      if ("UP".equals(entry.getValue())){
+      if (GossipState.UP.equals(entry.getValue())){
         up.add(entry.getKey());
       }
     }
@@ -91,14 +106,10 @@ public abstract class GossipManager extends Thread implements NotificationListen
     return _me;
   }
   
-  public void createOrRevivieMember(LocalGossipMember m){
-    members.put(m, "UP");
-  }
-
   public List<LocalGossipMember> getDeadList() {
     List<LocalGossipMember> up = new ArrayList<>();
-    for (Entry<LocalGossipMember, String> entry : members.entrySet()){
+    for (Entry<LocalGossipMember, GossipState> entry : members.entrySet()){
-      if ("DOWN".equals(entry.getValue())){
+      if (GossipState.DOWN.equals(entry.getValue())){
         up.add(entry.getKey());
       }
     }

src/main/java/com/google/code/gossip/manager/PassiveGossipThread.java

@@ -10,6 +10,7 @@ import java.util.ArrayList;
 import java.util.List;
 import java.util.concurrent.atomic.AtomicBoolean;
 
+import org.apache.log4j.Logger;
 import org.json.JSONArray;
 import org.json.JSONException;
 import org.json.JSONObject;
@@ -26,6 +27,8 @@ import com.google.code.gossip.RemoteGossipMember;
  */
 abstract public class PassiveGossipThread implements Runnable {
   
+  public static final Logger LOGGER = Logger.getLogger(PassiveGossipThread.class);
+
   /** The socket used for the passive thread of the gossip service. */
   private DatagramSocket _server;
 
@@ -107,8 +110,6 @@ abstract public class PassiveGossipThread implements Runnable {
               }
 
             }
-
-            // Merge our list with the one we just received
             mergeLists(_gossipManager, senderMember, remoteGossipMembers);
           } catch (JSONException e) {
             GossipService.LOGGER
@@ -122,7 +123,7 @@ abstract public class PassiveGossipThread implements Runnable {
         }
 
       } catch (IOException e) {
-        e.printStackTrace();
+        GossipService.LOGGER.error(e);
         _keepRunning.set(false);
       }
     }

src/main/java/com/google/code/gossip/manager/random/RandomActiveGossipThread.java

@@ -1,6 +1,5 @@
 package com.google.code.gossip.manager.random;
 
-import java.util.ArrayList;
 import java.util.List;
 import java.util.Random;
 

src/main/java/com/google/code/gossip/manager/random/RandomGossipManager.java

@@ -4,13 +4,14 @@ import java.util.ArrayList;
 
 import com.google.code.gossip.GossipMember;
 import com.google.code.gossip.GossipSettings;
+import com.google.code.gossip.event.GossipListener;
 import com.google.code.gossip.manager.GossipManager;
 import com.google.code.gossip.manager.impl.OnlyProcessReceivedPassiveGossipThread;
 
 public class RandomGossipManager extends GossipManager {
   public RandomGossipManager(String address, int port, String id, GossipSettings settings,
-          ArrayList<GossipMember> gossipMembers) {
+          ArrayList<GossipMember> gossipMembers, GossipListener listener) {
     super(OnlyProcessReceivedPassiveGossipThread.class, RandomActiveGossipThread.class, address,
-            port, id, settings, gossipMembers);
+            port, id, settings, gossipMembers, listener);
   }
 }

src/test/java/io/teknek/gossip/TenNodeThreeSeedTest.java

@@ -12,6 +12,8 @@ import com.google.code.gossip.GossipService;
 import com.google.code.gossip.GossipSettings;
 import com.google.code.gossip.LogLevel;
 import com.google.code.gossip.RemoteGossipMember;
+import com.google.code.gossip.event.GossipListener;
+import com.google.code.gossip.event.GossipState;
 
 public class TenNodeThreeSeedTest {
 
@@ -36,14 +38,20 @@ public class TenNodeThreeSeedTest {
     ArrayList<GossipService> clients = new ArrayList<GossipService>();
     int clusterMembers = 5;
     for (int i = 1; i < clusterMembers+1; ++i) {
-      GossipService gossipService = new GossipService("127.0.0."+i, 2000, i+"", LogLevel.DEBUG, startupMembers, settings);
+      GossipService gossipService = new GossipService("127.0.0." + i, 2000, i + "", LogLevel.DEBUG,
+              startupMembers, settings,
+              new GossipListener(){
+        @Override
+        public void gossipEvent(GossipMember member, GossipState state) {
+          System.out.println(member+" "+ state);
+        }
+      });
       clients.add(gossipService);
       gossipService.start();
       Thread.sleep(1000);
     }
     Thread.sleep(10000);
     for (int i = 0; i < clusterMembers; ++i) {
-      System.out.println(clients.get(i).get_gossipManager().getMemberList());
       Assert.assertEquals(4, clients.get(i).get_gossipManager().getMemberList().size());
     }
     for (int i = 0; i < clusterMembers; ++i) {