Leader reelection Attempt 1

Readme.md

@@ -7,8 +7,11 @@
 * Zookeeper Client Threading Model & Zookeeper Java API
 * Leader Election Implementation
 * Watchers, Triggers and Introduction to Failure Detection
+* Herd Effect 
+* Leader reelection Attempt 1 (with Herd Effect) 
 
 
 *Useful links*
 * [Class ZooKeeper](https://zookeeper.apache.org/doc/r3.9.1/apidocs/zookeeper-server/org/apache/zookeeper/ZooKeeper.html)
 * [wait notify and notifyall in java](https://javarevisited.blogspot.com/2011/05/wait-notify-and-notifyall-in-java.html)
+* [Zookeeper Tutorial](https://bikas-katwal.medium.com/zookeeper-introduction-designing-a-distributed-system-using-zookeeper-and-java-7f1b108e236e)
\ No newline at end of file

src/main/java/LeaderElection.java

@@ -33,7 +33,7 @@ public class LeaderElection implements Watcher {
     }
 
     public void electLeader() throws InterruptedException, KeeperException {
-        List<String> children = zooKeeper.getChildren(ELECTION_NAMESPACE, false);
+        List<String> children = zooKeeper.getChildren(ELECTION_NAMESPACE, this);
 
         Collections.sort(children);
         String smallestChild = children.get(0); //the first element
@@ -74,6 +74,15 @@ public class LeaderElection implements Watcher {
                 } else if (watchedEvent.getState() == Event.KeeperState.Closed) {
                     System.out.println("Closed Successfully");
                 }
+            case NodeChildrenChanged:
+                try {
+                    electLeader();
+                    System.out.println(ELECTION_NAMESPACE + " NodeChildrenChanged");
+                } catch (InterruptedException e) {
+                    throw new RuntimeException(e);
+                } catch (KeeperException e) {
+                    throw new RuntimeException(e);
+                }
 
         }
     }