Changes for BAEL-1532 (#3704)

* Changes for BAEL1532

* Changes for BAEL_1532

apache-zookeeper/pom.xml

@@ -0,0 +1,30 @@
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+	xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+	<modelVersion>4.0.0</modelVersion>
+	<groupId>com.baeldung</groupId>
+	<artifactId>apache-zookeeper</artifactId>
+	<version>0.0.1-SNAPSHOT</version>
+	<packaging>jar</packaging>
+
+	<dependencies>
+		<dependency>
+			<groupId>org.apache.zookeeper</groupId>
+			<artifactId>zookeeper</artifactId>
+			<version>3.3.2</version>
+			<exclusions>
+				<exclusion>
+					<groupId>com.sun.jmx</groupId>
+					<artifactId>jmxri</artifactId>
+				</exclusion>
+				<exclusion>
+					<groupId>com.sun.jdmk</groupId>
+					<artifactId>jmxtools</artifactId>
+				</exclusion>
+				<exclusion>
+					<groupId>javax.jms</groupId>
+					<artifactId>jms</artifactId>
+				</exclusion>
+			</exclusions>
+		</dependency>
+	</dependencies>
+</project>

apache-zookeeper/src/main/java/com/baeldung/zookeeper/connection/ZKConnection.java

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+package com.baeldung.zookeeper.connection;
+
+import java.io.IOException;
+import java.util.concurrent.CountDownLatch;
+
+import org.apache.zookeeper.WatchedEvent;
+import org.apache.zookeeper.Watcher;
+import org.apache.zookeeper.Watcher.Event.KeeperState;
+import org.apache.zookeeper.ZooKeeper;
+
+public class ZKConnection {
+    private ZooKeeper zoo;
+    final CountDownLatch connectionLatch = new CountDownLatch(1);
+
+    public ZKConnection() {
+    }
+
+    public ZooKeeper connect(String host) throws IOException, InterruptedException {
+        zoo = new ZooKeeper(host, 2000, new Watcher() {
+            public void process(WatchedEvent we) {
+                if (we.getState() == KeeperState.SyncConnected) {
+                    connectionLatch.countDown();
+                }
+            }
+        });
+        connectionLatch.await();
+        return zoo;
+    }
+
+    public void close() throws InterruptedException {
+        zoo.close();
+    }
+}

apache-zookeeper/src/main/java/com/baeldung/zookeeper/manager/ZKManager.java

@@ -0,0 +1,35 @@
+package com.baeldung.zookeeper.manager;
+
+import org.apache.zookeeper.KeeperException;
+
+public interface ZKManager {
+    /**
+     * Create a Znode and save some data
+     * 
+     * @param path
+     * @param data
+     * @throws KeeperException
+     * @throws InterruptedException
+     */
+    public void create(String path, byte[] data) throws KeeperException, InterruptedException;
+
+    /**
+     * Get ZNode Data
+     * 
+     * @param path
+     * @param boolean watchFlag
+     * @throws KeeperException
+     * @throws InterruptedException
+     */
+    public Object getZNodeData(String path, boolean watchFlag);
+
+    /**
+     * Update the ZNode Data
+     * 
+     * @param path
+     * @param data
+     * @throws KeeperException
+     * @throws InterruptedException
+     */
+    public void update(String path, byte[] data) throws KeeperException, InterruptedException, KeeperException;
+}

apache-zookeeper/src/main/java/com/baeldung/zookeeper/manager/ZKManagerImpl.java

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+package com.baeldung.zookeeper.manager;
+
+import org.apache.zookeeper.CreateMode;
+import org.apache.zookeeper.KeeperException;
+import org.apache.zookeeper.ZooDefs;
+import org.apache.zookeeper.ZooKeeper;
+
+import com.baeldung.zookeeper.connection.ZKConnection;
+
+public class ZKManagerImpl implements ZKManager {
+    private static ZooKeeper zkeeper;
+    private static ZKConnection zkConnection;
+
+    public ZKManagerImpl() {
+        initialize();
+    }
+
+    /** * Initialize connection */
+    private void initialize() {
+        try {
+            zkConnection = new ZKConnection();
+            zkeeper = zkConnection.connect("localhost");
+        } catch (Exception e) {
+            System.out.println(e.getMessage());
+        }
+    }
+
+    public void closeConnection() {
+        try {
+            zkConnection.close();
+        } catch (InterruptedException e) {
+            System.out.println(e.getMessage());
+        }
+    }
+
+    public void create(String path, byte[] data) throws KeeperException, InterruptedException {
+        zkeeper.create(path, data, ZooDefs.Ids.OPEN_ACL_UNSAFE, CreateMode.PERSISTENT);
+    }
+
+    public Object getZNodeData(String path, boolean watchFlag) {
+        try {
+            byte[] b = null;
+            b = zkeeper.getData(path, null, null);
+            String data = new String(b, "UTF-8");
+            System.out.println(data);
+            return data;
+        } catch (Exception e) {
+            System.out.println(e.getMessage());
+        }
+        return null;
+    }
+
+    public void update(String path, byte[] data) throws KeeperException, InterruptedException {
+        int version = zkeeper.exists(path, true)
+            .getVersion();
+        zkeeper.setData(path, data, version);
+    }
+}