diff --git a/leader-election/README.md b/leader-election/README.md
new file mode 100644
index 000000000..36c2670df
--- /dev/null
+++ b/leader-election/README.md
@@ -0,0 +1,31 @@
+---
+layout: pattern
+title: Leader Election
+folder: leader-election
+permalink: /patterns/leader-election/
+categories: Other
+tags:
+ - Java
+ - Difficulty-Beginner
+---
+
+## Intent
+Leader Election pattern is commonly used in cloud system design. It can help to ensure that task instances selec the leader instance correctly and do not conflict with each other, cause contention for shared resources, or inadvertently interfere with the work that other task instances are performing.
+
+## Applicability
+Use this pattern when
+
+* the tasks in a distributed application, such as a cloud-hosted solution, require careful coordination and there is no natural leader.
+
+Do not use this pattern when
+
+* there is a natural leader or dedicated process that can always act as the leader. For example, it may be possible to implement a singleton process that coordinates the task instances. If this process fails or becomes unhealthy, the system can shut it down and restart it.
+* the coordination between tasks can be easily achieved by using a more lightweight mechanism. For example, if several task instances simply require coordinated access to a shared resource, a preferable solution might be to use optimistic or pessimistic locking to control access to that resource.
+
+## Real world examples
+
+* [Raft Leader Election](https://github.com/ronenhamias/raft-leader-election)
+
+## Credits
+
+* [ Cloud Design Patterns: Prescriptive Architecture Guidance for Cloud Applications](https://docs.microsoft.com/en-us/previous-versions/msp-n-p/dn568104(v=pandp.10))
diff --git a/leader-election/pom.xml b/leader-election/pom.xml
new file mode 100644
index 000000000..7c1312d01
--- /dev/null
+++ b/leader-election/pom.xml
@@ -0,0 +1,43 @@
+
+
+
+ 4.0.0
+
+ java-design-patterns
+ com.iluwatar
+ 1.22.0-SNAPSHOT
+
+ leader-election
+
+
+ org.junit.jupiter
+ junit-jupiter-engine
+ test
+
+
+
\ No newline at end of file
diff --git a/leader-election/src/main/java/com/iluwatar/leaderelection/AbstractInstance.java b/leader-election/src/main/java/com/iluwatar/leaderelection/AbstractInstance.java
new file mode 100644
index 000000000..5f153870a
--- /dev/null
+++ b/leader-election/src/main/java/com/iluwatar/leaderelection/AbstractInstance.java
@@ -0,0 +1,148 @@
+/**
+ * The MIT License
+ * Copyright (c) 2014-2016 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+package com.iluwatar.leaderelection;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.util.Queue;
+import java.util.concurrent.ConcurrentLinkedQueue;
+
+/**
+ * Abstract class of all the instance implementation classes.
+ */
+public abstract class AbstractInstance implements Instance, Runnable {
+
+ private static final Logger LOGGER = LoggerFactory.getLogger(AbstractInstance.class);
+
+ protected static final int HEARTBEAT_INTERVAL = 5000;
+
+ protected MessageManager messageManager;
+ protected Queue messageQueue;
+ protected final int localId;
+ protected int leaderId;
+ protected boolean alive;
+
+ /**
+ * Constructor of BullyInstance.
+ */
+ public AbstractInstance(MessageManager messageManager, int localId, int leaderId) {
+ this.messageManager = messageManager;
+ this.messageQueue = new ConcurrentLinkedQueue<>();
+ this.localId = localId;
+ this.leaderId = leaderId;
+ this.alive = true;
+ }
+
+ /**
+ * The instance will execute the message in its message queue periodically once it is alive.
+ */
+ @Override
+ public void run() {
+ while (true) {
+ if (!this.messageQueue.isEmpty()) {
+ this.processMessage(this.messageQueue.remove());
+ }
+ }
+ }
+
+ /**
+ * Once messages are sent to the certain instance, it will firstly be added to the queue and wait to be executed.
+ * @param message Message sent by other instances
+ */
+ @Override
+ public void onMessage(Message message) {
+ messageQueue.offer(message);
+ }
+
+ /**
+ * Check if the instance is alive or not.
+ * @return {@code true} if the instance is alive.
+ */
+ @Override
+ public boolean isAlive() {
+ return alive;
+ }
+
+ /**
+ * Set the health status of the certain instance.
+ * @param alive {@code true} for alive.
+ */
+ @Override
+ public void setAlive(boolean alive) {
+ this.alive = alive;
+ }
+
+ /**
+ * Process the message according to its type.
+ * @param message Message polled from queue.
+ */
+ private void processMessage(Message message) {
+ switch (message.getType()) {
+ case ELECTION:
+ LOGGER.info("Instance " + localId + " - Election Message handling...");
+ handleElectionMessage(message);
+ break;
+ case LEADER:
+ LOGGER.info("Instance " + localId + " - Leader Message handling...");
+ handleLeaderMessage(message);
+ break;
+ case HEARTBEAT:
+ LOGGER.info("Instance " + localId + " - Heartbeat Message handling...");
+ handleHeartbeatMessage(message);
+ break;
+ case ELECTION_INVOKE:
+ LOGGER.info("Instance " + localId + " - Election Invoke Message handling...");
+ handleElectionInvokeMessage();
+ break;
+ case LEADER_INVOKE:
+ LOGGER.info("Instance " + localId + " - Leader Invoke Message handling...");
+ handleLeaderInvokeMessage();
+ break;
+ case HEARTBEAT_INVOKE:
+ LOGGER.info("Instance " + localId + " - Heartbeat Invoke Message handling...");
+ handleHeartbeatInvokeMessage();
+ break;
+ default:
+ break;
+ }
+ }
+
+ /**
+ * Abstract methods to handle different types of message. These methods need to be implemented in concrete instance
+ * class to implement corresponding leader-selection pattern.
+ */
+ protected abstract void handleElectionMessage(Message message);
+
+ protected abstract void handleElectionInvokeMessage();
+
+ protected abstract void handleLeaderMessage(Message message);
+
+ protected abstract void handleLeaderInvokeMessage();
+
+ protected abstract void handleHeartbeatMessage(Message message);
+
+ protected abstract void handleHeartbeatInvokeMessage();
+
+}
diff --git a/leader-election/src/main/java/com/iluwatar/leaderelection/AbstractMessageManager.java b/leader-election/src/main/java/com/iluwatar/leaderelection/AbstractMessageManager.java
new file mode 100644
index 000000000..4384da25f
--- /dev/null
+++ b/leader-election/src/main/java/com/iluwatar/leaderelection/AbstractMessageManager.java
@@ -0,0 +1,73 @@
+/**
+ * The MIT License
+ * Copyright (c) 2014-2016 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+package com.iluwatar.leaderelection;
+
+import java.util.List;
+import java.util.Map;
+import java.util.stream.Collectors;
+
+/**
+ * Abstract class of all the message manager classes.
+ */
+public abstract class AbstractMessageManager implements MessageManager {
+
+ /**
+ * Contain all the instances in the system. Key is its ID, and value is the instance itself.
+ */
+ protected Map instanceMap;
+
+ /**
+ * Construtor of AbstractMessageManager
+ */
+ public AbstractMessageManager(Map instanceMap) {
+ this.instanceMap = instanceMap;
+ }
+
+ /**
+ * Find the next instance with smallest ID.
+ * @return The next instance.
+ */
+ protected Instance findNextInstance(int currentId) {
+ Instance result = null;
+ List candidateList = instanceMap.keySet()
+ .stream()
+ .filter((i) -> i > currentId && instanceMap.get(i).isAlive())
+ .sorted()
+ .collect(Collectors.toList());
+ if (candidateList.isEmpty()) {
+ int index = instanceMap.keySet()
+ .stream()
+ .filter((i) -> instanceMap.get(i).isAlive())
+ .sorted()
+ .collect(Collectors.toList())
+ .get(0);
+ result = instanceMap.get(index);
+ } else {
+ int index = candidateList.get(0);
+ result = instanceMap.get(index);
+ }
+ return result;
+ }
+
+}
diff --git a/leader-election/src/main/java/com/iluwatar/leaderelection/Instance.java b/leader-election/src/main/java/com/iluwatar/leaderelection/Instance.java
new file mode 100644
index 000000000..abaa62791
--- /dev/null
+++ b/leader-election/src/main/java/com/iluwatar/leaderelection/Instance.java
@@ -0,0 +1,49 @@
+/**
+ * The MIT License
+ * Copyright (c) 2014-2016 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+package com.iluwatar.leaderelection;
+
+/**
+ * Instance interface
+ */
+public interface Instance {
+
+ /**
+ * Check if the instance is alive or not.
+ * @return {@code true} if the instance is alive.
+ */
+ boolean isAlive();
+
+ /**
+ * Set the health status of the certain instance.
+ * @param alive {@code true} for alive.
+ */
+ void setAlive(boolean alive);
+
+ /**
+ * Consume messages from other instances.
+ * @param message Message sent by other instances
+ */
+ void onMessage(Message message);
+
+}
diff --git a/leader-election/src/main/java/com/iluwatar/leaderelection/Message.java b/leader-election/src/main/java/com/iluwatar/leaderelection/Message.java
new file mode 100644
index 000000000..7ac79e4bc
--- /dev/null
+++ b/leader-election/src/main/java/com/iluwatar/leaderelection/Message.java
@@ -0,0 +1,76 @@
+/**
+ * The MIT License
+ * Copyright (c) 2014-2016 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+package com.iluwatar.leaderelection;
+
+import java.util.Objects;
+
+/**
+ * Message used to transport data between instances.
+ */
+public class Message {
+
+ private MessageType type;
+
+ private String content;
+
+ public Message() {}
+
+ public Message(MessageType type, String content) {
+ this.type = type;
+ this.content = content;
+ }
+
+ public MessageType getType() {
+ return type;
+ }
+
+ public void setType(MessageType type) {
+ this.type = type;
+ }
+
+ public String getContent() {
+ return content;
+ }
+
+ public void setContent(String content) {
+ this.content = content;
+ }
+
+ @Override
+ public boolean equals(Object o) {
+ if (this == o) {
+ return true;
+ }
+ if (o == null || getClass() != o.getClass()) {
+ return false;
+ }
+ Message message = (Message) o;
+ return type == message.type && Objects.equals(content, message.content);
+ }
+
+ @Override
+ public int hashCode() {
+ return Objects.hash(type, content);
+ }
+}
diff --git a/leader-election/src/main/java/com/iluwatar/leaderelection/MessageManager.java b/leader-election/src/main/java/com/iluwatar/leaderelection/MessageManager.java
new file mode 100644
index 000000000..56e78a008
--- /dev/null
+++ b/leader-election/src/main/java/com/iluwatar/leaderelection/MessageManager.java
@@ -0,0 +1,60 @@
+/**
+ * The MIT License
+ * Copyright (c) 2014-2016 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+package com.iluwatar.leaderelection;
+
+/**
+ * MessageManager interface
+ */
+public interface MessageManager {
+
+ /**
+ * Send heartbeat message to leader instance to check whether the leader instance is alive.
+ * @param leaderId Instance ID of leader instance.
+ * @return {@code true} if leader instance is alive, or {@code false} if not.
+ */
+ boolean sendHeartbeatMessage(int leaderId);
+
+ /**
+ * Send election message to other instances.
+ * @param currentId Instance ID of which sends this message.
+ * @param content Election message content.
+ * @return {@code true} if the message is accepted by the target instances.
+ */
+ boolean sendElectionMessage(int currentId, String content);
+
+ /**
+ * Send new leader notification message to other instances.
+ * @param currentId Instance ID of which sends this message.
+ * @param leaderId Leader message content.
+ * @return {@code true} if the message is accepted by the target instances.
+ */
+ boolean sendLeaderMessage(int currentId, int leaderId);
+
+ /**
+ * Send heartbeat invoke message. This will invoke heartbeat task in the target instance.
+ * @param currentId Instance ID of which sends this message.
+ */
+ void sendHeartbeatInvokeMessage(int currentId);
+
+}
diff --git a/leader-election/src/main/java/com/iluwatar/leaderelection/MessageType.java b/leader-election/src/main/java/com/iluwatar/leaderelection/MessageType.java
new file mode 100644
index 000000000..17f658ec4
--- /dev/null
+++ b/leader-election/src/main/java/com/iluwatar/leaderelection/MessageType.java
@@ -0,0 +1,62 @@
+/**
+ * The MIT License
+ * Copyright (c) 2014-2016 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+package com.iluwatar.leaderelection;
+
+/**
+ * Message Type enum
+ */
+public enum MessageType {
+
+ /**
+ * Start the election. The content of the message stores ID(s) of the candidate instance(s).
+ */
+ ELECTION,
+
+ /**
+ * Nodify the new leader. The content of the message should be the leader ID.
+ */
+ LEADER,
+
+ /**
+ * Check health of current leader instance.
+ */
+ HEARTBEAT,
+
+ /**
+ * Inform target instance to start election.
+ */
+ ELECTION_INVOKE,
+
+ /**
+ * Inform target instance to notify all the other instance that it is the new leader.
+ */
+ LEADER_INVOKE,
+
+ /**
+ * Inform target instance to start heartbeat.
+ */
+ HEARTBEAT_INVOKE
+
+}
+
diff --git a/leader-election/src/main/java/com/iluwatar/leaderelection/bully/BullyApp.java b/leader-election/src/main/java/com/iluwatar/leaderelection/bully/BullyApp.java
new file mode 100644
index 000000000..7355b3445
--- /dev/null
+++ b/leader-election/src/main/java/com/iluwatar/leaderelection/bully/BullyApp.java
@@ -0,0 +1,77 @@
+/**
+ * The MIT License
+ * Copyright (c) 2014-2016 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+package com.iluwatar.leaderelection.bully;
+
+import com.iluwatar.leaderelection.Instance;
+import com.iluwatar.leaderelection.Message;
+import com.iluwatar.leaderelection.MessageManager;
+import com.iluwatar.leaderelection.MessageType;
+
+import java.util.HashMap;
+import java.util.Map;
+
+/**
+ * Example of how to use bully leader election. Initially 5 instances is created in the clould
+ * system, and the instance with ID 1 is set as leader. After the system is started stop the
+ * leader instance, and the new leader will be elected.
+ */
+public class BullyApp {
+
+ /**
+ * Program entry point
+ */
+ public static void main(String[] args) {
+
+ Map instanceMap = new HashMap<>();
+ MessageManager messageManager = new BullyMessageManager(instanceMap);
+
+ BullyInstance instance1 = new BullyInstance(messageManager, 1, 1);
+ BullyInstance instance2 = new BullyInstance(messageManager, 2, 1);
+ BullyInstance instance3 = new BullyInstance(messageManager, 3, 1);
+ BullyInstance instance4 = new BullyInstance(messageManager, 4, 1);
+ BullyInstance instance5 = new BullyInstance(messageManager, 5, 1);
+
+ instanceMap.put(1, instance1);
+ instanceMap.put(2, instance2);
+ instanceMap.put(3, instance3);
+ instanceMap.put(4, instance4);
+ instanceMap.put(5, instance5);
+
+ instance4.onMessage(new Message(MessageType.HEARTBEAT_INVOKE, ""));
+
+ Thread thread1 = new Thread(instance1);
+ Thread thread2 = new Thread(instance2);
+ Thread thread3 = new Thread(instance3);
+ Thread thread4 = new Thread(instance4);
+ Thread thread5 = new Thread(instance5);
+
+ thread1.start();
+ thread2.start();
+ thread3.start();
+ thread4.start();
+ thread5.start();
+
+ instance1.setAlive(false);
+ }
+}
diff --git a/leader-election/src/main/java/com/iluwatar/leaderelection/bully/BullyInstance.java b/leader-election/src/main/java/com/iluwatar/leaderelection/bully/BullyInstance.java
new file mode 100644
index 000000000..70a9c60f3
--- /dev/null
+++ b/leader-election/src/main/java/com/iluwatar/leaderelection/bully/BullyInstance.java
@@ -0,0 +1,121 @@
+/**
+ * The MIT License
+ * Copyright (c) 2014-2016 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+package com.iluwatar.leaderelection.bully;
+
+import com.iluwatar.leaderelection.AbstractInstance;
+import com.iluwatar.leaderelection.Message;
+import com.iluwatar.leaderelection.MessageManager;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+/**
+ * Impelemetation with bully algorithm. Each instance should have a sequential id and is able to
+ * communicate with other instances in the system. Initially the instance with smallest (or largest)
+ * ID is selected to be the leader. All the other instances send heartbeat message to leader periodically
+ * to check its health. If one certain instance finds the server done, it will send an election message
+ * to all the instances of which the ID is larger. If the target instance is alive, it will return an
+ * alive message (in this sample return true) and then send election message with its ID. If not,
+ * the original instance will send leader message to all the other instances.
+ */
+public class BullyInstance extends AbstractInstance {
+
+ private static final Logger LOGGER = LoggerFactory.getLogger(BullyInstance.class);
+
+ /**
+ * Constructor of BullyInstance.
+ */
+ public BullyInstance(MessageManager messageManager, int localId, int leaderId) {
+ super(messageManager, localId, leaderId);
+ }
+
+ /**
+ * Process the heartbeat invoke message. After receiving the message, the instance will send a heartbeat
+ * to leader to check its health. If alive, it will inform the next instance to do the heartbeat. If not,
+ * it will start the election process.
+ */
+ @Override
+ protected void handleHeartbeatInvokeMessage() {
+ try {
+ boolean isLeaderAlive = messageManager.sendHeartbeatMessage(leaderId);
+ if (isLeaderAlive) {
+ LOGGER.info("Instance " + localId + "- Leader is alive.");
+ Thread.sleep(HEARTBEAT_INTERVAL);
+ messageManager.sendHeartbeatInvokeMessage(localId);
+ } else {
+ LOGGER.info("Instance " + localId + "- Leader is not alive. Start election.");
+ boolean electionResult = messageManager.sendElectionMessage(localId, String.valueOf(localId));
+ if (electionResult) {
+ LOGGER.info("Instance " + localId + "- Succeed in election. Start leader notification.");
+ messageManager.sendLeaderMessage(localId, localId);
+ }
+ }
+ } catch (InterruptedException e) {
+ LOGGER.info("Instance " + localId + "- Interrupted.");
+ }
+ }
+
+ /**
+ * Process election invoke message. Send election message to all the instances with smaller ID. If any
+ * one of them is alive, do nothing. If no instance alive, send leader message to all the alive instance
+ * and restart heartbeat.
+ */
+ @Override
+ protected void handleElectionInvokeMessage() {
+ if (!isLeader()) {
+ LOGGER.info("Instance " + localId + "- Start election.");
+ boolean electionResult = messageManager.sendElectionMessage(localId, String.valueOf(localId));
+ if (electionResult) {
+ LOGGER.info("Instance " + localId + "- Succeed in election. Start leader notification.");
+ leaderId = localId;
+ messageManager.sendLeaderMessage(localId, localId);
+ messageManager.sendHeartbeatInvokeMessage(localId);
+ }
+ }
+ }
+
+ /**
+ * Process leader message. Update local leader information.
+ */
+ @Override
+ protected void handleLeaderMessage(Message message) {
+ leaderId = Integer.valueOf(message.getContent());
+ LOGGER.info("Instance " + localId + " - Leader update done.");
+ }
+
+ private boolean isLeader() {
+ return localId == leaderId;
+ }
+
+ /**
+ * Not used in Bully instance.
+ */
+ @Override
+ protected void handleLeaderInvokeMessage() {}
+
+ @Override
+ protected void handleHeartbeatMessage(Message message) {}
+
+ @Override
+ protected void handleElectionMessage(Message message) {}
+}
diff --git a/leader-election/src/main/java/com/iluwatar/leaderelection/bully/BullyMessageManager.java b/leader-election/src/main/java/com/iluwatar/leaderelection/bully/BullyMessageManager.java
new file mode 100644
index 000000000..3fcadefba
--- /dev/null
+++ b/leader-election/src/main/java/com/iluwatar/leaderelection/bully/BullyMessageManager.java
@@ -0,0 +1,117 @@
+/**
+ * The MIT License
+ * Copyright (c) 2014-2016 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+package com.iluwatar.leaderelection.bully;
+
+import com.iluwatar.leaderelection.AbstractMessageManager;
+import com.iluwatar.leaderelection.Instance;
+import com.iluwatar.leaderelection.Message;
+import com.iluwatar.leaderelection.MessageType;
+
+import java.util.List;
+import java.util.Map;
+import java.util.stream.Collectors;
+
+/**
+ * Implementation of BullyMessageManager
+ */
+public class BullyMessageManager extends AbstractMessageManager {
+
+ /**
+ * Constructor of BullyMessageManager.
+ */
+ public BullyMessageManager(Map instanceMap) {
+ super(instanceMap);
+ }
+
+ /**
+ * Send heartbeat message to current leader instance to check the health.
+ * @param leaderId leaderID
+ * @return {@code true} if the leader is alive.
+ */
+ @Override
+ public boolean sendHeartbeatMessage(int leaderId) {
+ Instance leaderInstance = instanceMap.get(leaderId);
+ boolean alive = leaderInstance.isAlive();
+ return alive;
+ }
+
+ /**
+ * Send election message to all the instances with smaller ID.
+ * @param currentId Instance ID of which sends this message.
+ * @param content Election message content.
+ * @return {@code true} if no alive instance has smaller ID, so that the election is accepted.
+ */
+ @Override
+ public boolean sendElectionMessage(int currentId, String content) {
+ List candidateList = findElectionCandidateInstanceList(currentId);
+ if (candidateList.isEmpty()) {
+ return true;
+ } else {
+ Message electionMessage = new Message(MessageType.ELECTION_INVOKE, "");
+ candidateList.stream()
+ .forEach((i) -> instanceMap.get(i).onMessage(electionMessage));
+ return false;
+ }
+ }
+
+ /**
+ * Send leader message to all the instances to notify the new leader.
+ * @param currentId Instance ID of which sends this message.
+ * @param leaderId Leader message content.
+ * @return {@code true} if the message is accepted.
+ */
+ @Override
+ public boolean sendLeaderMessage(int currentId, int leaderId) {
+ Message leaderMessage = new Message(MessageType.LEADER, String.valueOf(leaderId));
+ instanceMap.keySet()
+ .stream()
+ .filter((i) -> i != currentId)
+ .forEach((i) -> instanceMap.get(i).onMessage(leaderMessage));
+ return false;
+ }
+
+ /**
+ * Send heartbeat invoke message to the next instance.
+ * @param currentId Instance ID of which sends this message.
+ */
+ @Override
+ public void sendHeartbeatInvokeMessage(int currentId) {
+ Instance nextInstance = this.findNextInstance(currentId);
+ Message heartbeatInvokeMessage = new Message(MessageType.HEARTBEAT_INVOKE, "");
+ nextInstance.onMessage(heartbeatInvokeMessage);
+ }
+
+ /**
+ * Find all the alive instances with smaller ID than current instance.
+ * @param currentId ID of current instance.
+ * @return ID list of all the candidate instance.
+ */
+ private List findElectionCandidateInstanceList(int currentId) {
+ return instanceMap.keySet()
+ .stream()
+ .filter((i) -> i < currentId && instanceMap.get(i).isAlive())
+ .collect(Collectors.toList());
+ }
+
+}
diff --git a/leader-election/src/main/java/com/iluwatar/leaderelection/ring/RingApp.java b/leader-election/src/main/java/com/iluwatar/leaderelection/ring/RingApp.java
new file mode 100644
index 000000000..ade5bb70d
--- /dev/null
+++ b/leader-election/src/main/java/com/iluwatar/leaderelection/ring/RingApp.java
@@ -0,0 +1,77 @@
+/**
+ * The MIT License
+ * Copyright (c) 2014-2016 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+package com.iluwatar.leaderelection.ring;
+
+import com.iluwatar.leaderelection.Instance;
+import com.iluwatar.leaderelection.Message;
+import com.iluwatar.leaderelection.MessageManager;
+import com.iluwatar.leaderelection.MessageType;
+
+import java.util.HashMap;
+import java.util.Map;
+
+/**
+ * Example of how to use ring leader election. Initially 5 instances is created in the clould
+ * system, and the instance with ID 1 is set as leader. After the system is started stop the
+ * leader instance, and the new leader will be elected.
+ */
+public class RingApp {
+
+ /**
+ * Program entry point
+ */
+ public static void main(String[] args) {
+
+ Map instanceMap = new HashMap<>();
+ MessageManager messageManager = new RingMessageManager(instanceMap);
+
+ RingInstance instance1 = new RingInstance(messageManager, 1, 1);
+ RingInstance instance2 = new RingInstance(messageManager, 2, 1);
+ RingInstance instance3 = new RingInstance(messageManager, 3, 1);
+ RingInstance instance4 = new RingInstance(messageManager, 4, 1);
+ RingInstance instance5 = new RingInstance(messageManager, 5, 1);
+
+ instanceMap.put(1, instance1);
+ instanceMap.put(2, instance2);
+ instanceMap.put(3, instance3);
+ instanceMap.put(4, instance4);
+ instanceMap.put(5, instance5);
+
+ instance2.onMessage(new Message(MessageType.HEARTBEAT_INVOKE, ""));
+
+ Thread thread1 = new Thread(instance1);
+ Thread thread2 = new Thread(instance2);
+ Thread thread3 = new Thread(instance3);
+ Thread thread4 = new Thread(instance4);
+ Thread thread5 = new Thread(instance5);
+
+ thread1.start();
+ thread2.start();
+ thread3.start();
+ thread4.start();
+ thread5.start();
+
+ instance1.setAlive(false);
+ }
+}
diff --git a/leader-election/src/main/java/com/iluwatar/leaderelection/ring/RingInstance.java b/leader-election/src/main/java/com/iluwatar/leaderelection/ring/RingInstance.java
new file mode 100644
index 000000000..e3472e4b4
--- /dev/null
+++ b/leader-election/src/main/java/com/iluwatar/leaderelection/ring/RingInstance.java
@@ -0,0 +1,133 @@
+/**
+ * The MIT License
+ * Copyright (c) 2014-2016 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+package com.iluwatar.leaderelection.ring;
+
+import com.iluwatar.leaderelection.AbstractInstance;
+import com.iluwatar.leaderelection.Message;
+import com.iluwatar.leaderelection.MessageManager;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.util.Arrays;
+import java.util.List;
+import java.util.stream.Collectors;
+
+/**
+ * Implementation with token ring algorithm. The instances in the system are organized as a ring.
+ * Each instance should have a sequential id and the instance with smallest (or largest) id should
+ * be the initial leader. All the other instances send heartbeat message to leader periodically
+ * to check its health. If one certain instance finds the server done, it will send an election
+ * message to the next alive instance in the ring, which contains its own ID. Then the next instance
+ * add its ID into the message and pass it to the next. After all the alive instances' ID are add
+ * to the message, the message is send back to the first instance and it will choose the instance
+ * with smallest ID to be the new leader, and then send a leader message to other instances to
+ * inform the result.
+ */
+public class RingInstance extends AbstractInstance {
+
+ private static final Logger LOGGER = LoggerFactory.getLogger(RingInstance.class);
+
+ /**
+ * Constructor of RingInstance.
+ */
+ public RingInstance(MessageManager messageManager, int localId, int leaderId) {
+ super(messageManager, localId, leaderId);
+ }
+
+ /**
+ * Process the heartbeat invoke message. After receiving the message, the instance will send a heartbeat
+ * to leader to check its health. If alive, it will inform the next instance to do the heartbeat. If not,
+ * it will start the election process.
+ */
+ @Override
+ protected void handleHeartbeatInvokeMessage() {
+ try {
+ boolean isLeaderAlive = messageManager.sendHeartbeatMessage(this.leaderId);
+ if (isLeaderAlive) {
+ LOGGER.info("Instance " + localId + "- Leader is alive. Start next heartbeat in 5 second.");
+ Thread.sleep(HEARTBEAT_INTERVAL);
+ messageManager.sendHeartbeatInvokeMessage(this.localId);
+ } else {
+ LOGGER.info("Instance " + localId + "- Leader is not alive. Start election.");
+ messageManager.sendElectionMessage(this.localId, String.valueOf(this.localId));
+ }
+ } catch (InterruptedException e) {
+ LOGGER.info("Instance " + localId + "- Interrupted.");
+ }
+ }
+
+ /**
+ * Process election message. If the local ID is contained in the ID list, the instance will select the
+ * alive instance with smallest ID to be the new leader, and send the leader inform message. If not,
+ * it will add its local ID to the list and send the message to the next instance in the ring.
+ */
+ @Override
+ protected void handleElectionMessage(Message message) {
+ String content = message.getContent();
+ LOGGER.info("Instance " + localId + " - Election Message: " + content);
+ List candidateList =
+ Arrays.stream(content.trim().split(","))
+ .map(Integer::valueOf)
+ .sorted()
+ .collect(Collectors.toList());
+ if (candidateList.contains(localId)) {
+ int newLeaderId = candidateList.get(0);
+ LOGGER.info("Instance " + localId + " - New leader should be " + newLeaderId + ".");
+ messageManager.sendLeaderMessage(localId, newLeaderId);
+ } else {
+ content += "," + localId;
+ messageManager.sendElectionMessage(localId, content);
+ }
+ }
+
+ /**
+ * Process leader Message. The instance will set the leader ID to be the new one and send the message to
+ * the next instance until all the alive instance in the ring is informed.
+ */
+ @Override
+ protected void handleLeaderMessage(Message message) {
+ int newLeaderId = Integer.valueOf(message.getContent());
+ if (this.leaderId != newLeaderId) {
+ LOGGER.info("Instance " + localId + " - Update leaderID");
+ this.leaderId = newLeaderId;
+ messageManager.sendLeaderMessage(localId, newLeaderId);
+ } else {
+ LOGGER.info("Instance " + localId + " - Leader update done. Start heartbeat.");
+ messageManager.sendHeartbeatInvokeMessage(localId);
+ }
+ }
+
+ /**
+ * Not used in Ring instance.
+ */
+ @Override
+ protected void handleLeaderInvokeMessage() {}
+
+ @Override
+ protected void handleHeartbeatMessage(Message message) {}
+
+ @Override
+ protected void handleElectionInvokeMessage() {}
+
+}
diff --git a/leader-election/src/main/java/com/iluwatar/leaderelection/ring/RingMessageManager.java b/leader-election/src/main/java/com/iluwatar/leaderelection/ring/RingMessageManager.java
new file mode 100644
index 000000000..257a9f764
--- /dev/null
+++ b/leader-election/src/main/java/com/iluwatar/leaderelection/ring/RingMessageManager.java
@@ -0,0 +1,96 @@
+/**
+ * The MIT License
+ * Copyright (c) 2014-2016 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+package com.iluwatar.leaderelection.ring;
+
+import com.iluwatar.leaderelection.AbstractMessageManager;
+import com.iluwatar.leaderelection.Instance;
+import com.iluwatar.leaderelection.Message;
+import com.iluwatar.leaderelection.MessageType;
+
+import java.util.Map;
+
+/**
+ * Implementation of RingMessageManager
+ */
+public class RingMessageManager extends AbstractMessageManager {
+
+ /**
+ * Constructor of RingMessageManager.
+ */
+ public RingMessageManager(Map instanceMap) {
+ super(instanceMap);
+ }
+
+ /**
+ * Send heartbeat message to current leader instance to check the health.
+ * @param leaderId leaderID
+ * @return {@code true} if the leader is alive.
+ */
+ @Override
+ public boolean sendHeartbeatMessage(int leaderId) {
+ Instance leaderInstance = instanceMap.get(leaderId);
+ boolean alive = leaderInstance.isAlive();
+ return alive;
+ }
+
+ /**
+ * Send election message to the next instance.
+ * @param currentId currentID
+ * @param content list contains all the IDs of instances which have received this election message.
+ * @return {@code true} if the election message is accepted by the target instance.
+ */
+ @Override
+ public boolean sendElectionMessage(int currentId, String content) {
+ Instance nextInstance = this.findNextInstance(currentId);
+ Message electionMessage = new Message(MessageType.ELECTION, content);
+ nextInstance.onMessage(electionMessage);
+ return true;
+ }
+
+ /**
+ * Send leader message to the next instance.
+ * @param currentId Instance ID of which sends this message.
+ * @param leaderId Leader message content.
+ * @return {@code true} if the leader message is accepted by the target instance.
+ */
+ @Override
+ public boolean sendLeaderMessage(int currentId, int leaderId) {
+ Instance nextInstance = this.findNextInstance(currentId);
+ Message leaderMessage = new Message(MessageType.LEADER, String.valueOf(leaderId));
+ nextInstance.onMessage(leaderMessage);
+ return true;
+ }
+
+ /**
+ * Send heartbeat invoke message to the next instance.
+ * @param currentId Instance ID of which sends this message.
+ */
+ @Override
+ public void sendHeartbeatInvokeMessage(int currentId) {
+ Instance nextInstance = this.findNextInstance(currentId);
+ Message heartbeatInvokeMessage = new Message(MessageType.HEARTBEAT_INVOKE, "");
+ nextInstance.onMessage(heartbeatInvokeMessage);
+ }
+
+}
diff --git a/leader-election/src/test/java/com/iluwatar/leaderelection/MessageTest.java b/leader-election/src/test/java/com/iluwatar/leaderelection/MessageTest.java
new file mode 100644
index 000000000..3cd5b93d9
--- /dev/null
+++ b/leader-election/src/test/java/com/iluwatar/leaderelection/MessageTest.java
@@ -0,0 +1,48 @@
+/**
+ * The MIT License
+ * Copyright (c) 2014-2016 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+package com.iluwatar.leaderelection;
+
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+/**
+ * Message test case.
+ */
+public class MessageTest {
+
+ @Test
+ public void testGetType() {
+ Message message = new Message(MessageType.HEARTBEAT, "");
+ assertEquals(MessageType.HEARTBEAT, message.getType());
+ }
+
+ @Test
+ public void testGetContent() {
+ String content = "test";
+ Message message = new Message(MessageType.HEARTBEAT, content);
+ assertEquals(content, message.getContent());
+ }
+
+}
diff --git a/leader-election/src/test/java/com/iluwatar/leaderelection/bully/BullyAppTest.java b/leader-election/src/test/java/com/iluwatar/leaderelection/bully/BullyAppTest.java
new file mode 100644
index 000000000..b4b527d5a
--- /dev/null
+++ b/leader-election/src/test/java/com/iluwatar/leaderelection/bully/BullyAppTest.java
@@ -0,0 +1,39 @@
+/**
+ * The MIT License
+ * Copyright (c) 2014-2016 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+package com.iluwatar.leaderelection.bully;
+
+import org.junit.jupiter.api.Test;
+
+/**
+ * BullyApp unit test.
+ */
+public class BullyAppTest {
+
+ @Test
+ public void test() {
+ String[] args = {};
+ BullyApp.main(args);
+ }
+
+}
diff --git a/leader-election/src/test/java/com/iluwatar/leaderelection/bully/BullyMessageManagerTest.java b/leader-election/src/test/java/com/iluwatar/leaderelection/bully/BullyMessageManagerTest.java
new file mode 100644
index 000000000..3a8e35b54
--- /dev/null
+++ b/leader-election/src/test/java/com/iluwatar/leaderelection/bully/BullyMessageManagerTest.java
@@ -0,0 +1,151 @@
+/**
+ * The MIT License
+ * Copyright (c) 2014-2016 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+package com.iluwatar.leaderelection.bully;
+
+import com.iluwatar.leaderelection.*;
+import com.iluwatar.leaderelection.ring.RingInstance;
+import com.iluwatar.leaderelection.ring.RingMessageManager;
+import org.junit.jupiter.api.Test;
+
+import java.lang.reflect.Field;
+import java.util.HashMap;
+import java.util.Map;
+import java.util.Queue;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+/**
+ * BullyMessageManager unit test.
+ */
+public class BullyMessageManagerTest {
+
+ @Test
+ public void testSendHeartbeatMessage() {
+ Instance instance1 = new BullyInstance(null, 1, 1);
+ Map instanceMap = new HashMap<>();
+ instanceMap.put(1, instance1);
+ MessageManager messageManager = new BullyMessageManager(instanceMap);
+ assertTrue(messageManager.sendHeartbeatMessage(1));
+ }
+
+ @Test
+ public void testSendElectionMessageNotAccepted() {
+ try {
+ Instance instance1 = new BullyInstance(null, 1, 1);
+ Instance instance2 = new BullyInstance(null, 1, 2);
+ Instance instance3 = new BullyInstance(null, 1, 3);
+ Instance instance4 = new BullyInstance(null, 1, 4);
+ Map instanceMap = new HashMap<>();
+ instanceMap.put(1, instance1);
+ instanceMap.put(2, instance2);
+ instanceMap.put(3, instance3);
+ instanceMap.put(4, instance4);
+ instance1.setAlive(false);
+ MessageManager messageManager = new BullyMessageManager(instanceMap);
+ boolean result = messageManager.sendElectionMessage(3, "3");
+ Class instanceClass = AbstractInstance.class;
+ Field messageQueueField = instanceClass.getDeclaredField("messageQueue");
+ messageQueueField.setAccessible(true);
+ Message message2 = ((Queue) messageQueueField.get(instance2)).poll();
+ int instance4QueueSize = ((Queue) messageQueueField.get(instance4)).size();
+ Message expectedMessage = new Message(MessageType.ELECTION_INVOKE, "");
+ assertEquals(message2, expectedMessage);
+ assertEquals(instance4QueueSize, 0);
+ assertEquals(result, false);
+ } catch (IllegalAccessException | NoSuchFieldException e) {
+ fail("Error to access private field.");
+ }
+ }
+
+ @Test
+ public void testElectionMessageAccepted() {
+ Instance instance1 = new BullyInstance(null, 1, 1);
+ Instance instance2 = new BullyInstance(null, 1, 2);
+ Instance instance3 = new BullyInstance(null, 1, 3);
+ Instance instance4 = new BullyInstance(null, 1, 4);
+ Map instanceMap = new HashMap<>();
+ instanceMap.put(1, instance1);
+ instanceMap.put(2, instance2);
+ instanceMap.put(3, instance3);
+ instanceMap.put(4, instance4);
+ instance1.setAlive(false);
+ MessageManager messageManager = new BullyMessageManager(instanceMap);
+ boolean result = messageManager.sendElectionMessage(2, "2");
+ assertEquals(result, true);
+ }
+
+ @Test
+ public void testSendLeaderMessage() {
+ try {
+ Instance instance1 = new BullyInstance(null, 1, 1);
+ Instance instance2 = new BullyInstance(null, 1, 2);
+ Instance instance3 = new BullyInstance(null, 1, 3);
+ Instance instance4 = new BullyInstance(null, 1, 4);
+ Map instanceMap = new HashMap<>();
+ instanceMap.put(1, instance1);
+ instanceMap.put(2, instance2);
+ instanceMap.put(3, instance3);
+ instanceMap.put(4, instance4);
+ instance1.setAlive(false);
+ MessageManager messageManager = new BullyMessageManager(instanceMap);
+ messageManager.sendLeaderMessage(2, 2);
+ Class instanceClass = AbstractInstance.class;
+ Field messageQueueField = instanceClass.getDeclaredField("messageQueue");
+ messageQueueField.setAccessible(true);
+ Message message3 = ((Queue) messageQueueField.get(instance3)).poll();
+ Message message4 = ((Queue) messageQueueField.get(instance4)).poll();
+ Message expectedMessage = new Message(MessageType.LEADER, "2");
+ assertEquals(message3, expectedMessage);
+ assertEquals(message4, expectedMessage);
+ } catch (IllegalAccessException | NoSuchFieldException e) {
+ fail("Error to access private field.");
+ }
+ }
+
+ @Test
+ public void testSendHeartbeatInvokeMessage() {
+ try {
+ Instance instance1 = new BullyInstance(null, 1, 1);
+ Instance instance2 = new BullyInstance(null, 1, 2);
+ Instance instance3 = new BullyInstance(null, 1, 3);
+ Map instanceMap = new HashMap<>();
+ instanceMap.put(1, instance1);
+ instanceMap.put(2, instance2);
+ instanceMap.put(3, instance3);
+ MessageManager messageManager = new BullyMessageManager(instanceMap);
+ messageManager.sendHeartbeatInvokeMessage(2);
+ Message message = new Message(MessageType.HEARTBEAT_INVOKE, "");
+ Class instanceClass = AbstractInstance.class;
+ Field messageQueueField = instanceClass.getDeclaredField("messageQueue");
+ messageQueueField.setAccessible(true);
+ Message messageSent = ((Queue) messageQueueField.get(instance3)).poll();
+ assertEquals(messageSent.getType(), message.getType());
+ assertEquals(messageSent.getContent(), message.getContent());
+ } catch (NoSuchFieldException | IllegalAccessException e) {
+ fail("Error to access private field.");
+ }
+ }
+
+
+}
diff --git a/leader-election/src/test/java/com/iluwatar/leaderelection/bully/BullyinstanceTest.java b/leader-election/src/test/java/com/iluwatar/leaderelection/bully/BullyinstanceTest.java
new file mode 100644
index 000000000..7581a8af1
--- /dev/null
+++ b/leader-election/src/test/java/com/iluwatar/leaderelection/bully/BullyinstanceTest.java
@@ -0,0 +1,78 @@
+/**
+ * The MIT License
+ * Copyright (c) 2014-2016 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+package com.iluwatar.leaderelection.bully;
+
+import com.iluwatar.leaderelection.AbstractInstance;
+import com.iluwatar.leaderelection.Message;
+import com.iluwatar.leaderelection.MessageType;
+import org.junit.jupiter.api.Test;
+
+import java.lang.reflect.Field;
+import java.util.Queue;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+/**
+ * BullyInstance unit test.
+ */
+public class BullyinstanceTest {
+
+ @Test
+ public void testOnMessage() {
+ try {
+ final BullyInstance bullyInstance = new BullyInstance(null, 1, 1);
+ Message bullyMessage = new Message(MessageType.HEARTBEAT, "");
+ bullyInstance.onMessage(bullyMessage);
+ Class instanceClass = AbstractInstance.class;
+ Field messageQueueField = instanceClass.getDeclaredField("messageQueue");
+ messageQueueField.setAccessible(true);
+ assertEquals(bullyMessage, ((Queue) messageQueueField.get(bullyInstance)).poll());
+ } catch (IllegalAccessException | NoSuchFieldException e) {
+ fail("fail to access messasge queue.");
+ }
+
+ }
+
+ @Test
+ public void testIsAlive() {
+ try {
+ final BullyInstance bullyInstance = new BullyInstance(null, 1, 1);
+ Class instanceClass = AbstractInstance.class;
+ Field aliveField = instanceClass.getDeclaredField("alive");
+ aliveField.setAccessible(true);
+ aliveField.set(bullyInstance, false);
+ assertFalse(bullyInstance.isAlive());
+ } catch (NoSuchFieldException | IllegalAccessException e) {
+ fail("Fail to access field alive.");
+ }
+ }
+
+ @Test
+ public void testSetAlive() {
+ final BullyInstance bullyInstance = new BullyInstance(null, 1, 1);
+ bullyInstance.setAlive(false);
+ assertFalse(bullyInstance.isAlive());
+ }
+
+}
diff --git a/leader-election/src/test/java/com/iluwatar/leaderelection/ring/RingAppTest.java b/leader-election/src/test/java/com/iluwatar/leaderelection/ring/RingAppTest.java
new file mode 100644
index 000000000..c6f50bc79
--- /dev/null
+++ b/leader-election/src/test/java/com/iluwatar/leaderelection/ring/RingAppTest.java
@@ -0,0 +1,39 @@
+/**
+ * The MIT License
+ * Copyright (c) 2014-2016 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+package com.iluwatar.leaderelection.ring;
+
+import org.junit.jupiter.api.Test;
+
+/**
+ * RingApp unit test.
+ */
+public class RingAppTest {
+
+ @Test
+ public void test() {
+ String[] args = {};
+ RingApp.main(args);
+ }
+
+}
diff --git a/leader-election/src/test/java/com/iluwatar/leaderelection/ring/RingInstanceTest.java b/leader-election/src/test/java/com/iluwatar/leaderelection/ring/RingInstanceTest.java
new file mode 100644
index 000000000..65c3916cc
--- /dev/null
+++ b/leader-election/src/test/java/com/iluwatar/leaderelection/ring/RingInstanceTest.java
@@ -0,0 +1,76 @@
+/**
+ * The MIT License
+ * Copyright (c) 2014-2016 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+package com.iluwatar.leaderelection.ring;
+
+import com.iluwatar.leaderelection.AbstractInstance;
+import com.iluwatar.leaderelection.Message;
+import com.iluwatar.leaderelection.MessageType;
+import org.junit.jupiter.api.Test;
+
+import java.lang.reflect.Field;
+import java.util.Queue;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+/**
+ * RingInstance unit test.
+ */
+public class RingInstanceTest {
+
+ @Test
+ public void testOnMessage() {
+ try {
+ final RingInstance ringInstance = new RingInstance(null, 1, 1);
+ Message ringMessage = new Message(MessageType.HEARTBEAT, "");
+ ringInstance.onMessage(ringMessage);
+ Class ringInstanceClass = AbstractInstance.class;
+ Field messageQueueField = ringInstanceClass.getDeclaredField("messageQueue");
+ messageQueueField.setAccessible(true);
+ assertEquals(ringMessage, ((Queue) messageQueueField.get(ringInstance)).poll());
+ } catch (IllegalAccessException | NoSuchFieldException e) {
+ fail("fail to access messasge queue.");
+ }
+ }
+
+ @Test
+ public void testIsAlive() {
+ try {
+ final RingInstance ringInstance = new RingInstance(null, 1, 1);
+ Class ringInstanceClass = AbstractInstance.class;
+ Field aliveField = ringInstanceClass.getDeclaredField("alive");
+ aliveField.setAccessible(true);
+ aliveField.set(ringInstance, false);
+ assertFalse(ringInstance.isAlive());
+ } catch (NoSuchFieldException | IllegalAccessException e) {
+ fail("Fail to access field alive.");
+ }
+ }
+
+ @Test
+ public void testSetAlive() {
+ final RingInstance ringInstance = new RingInstance(null, 1, 1);
+ ringInstance.setAlive(false);
+ assertFalse(ringInstance.isAlive());
+ }
+}
diff --git a/leader-election/src/test/java/com/iluwatar/leaderelection/ring/RingMessageManagerTest.java b/leader-election/src/test/java/com/iluwatar/leaderelection/ring/RingMessageManagerTest.java
new file mode 100644
index 000000000..64d5af69f
--- /dev/null
+++ b/leader-election/src/test/java/com/iluwatar/leaderelection/ring/RingMessageManagerTest.java
@@ -0,0 +1,123 @@
+/**
+ * The MIT License
+ * Copyright (c) 2014-2016 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+package com.iluwatar.leaderelection.ring;
+
+import com.iluwatar.leaderelection.*;
+import org.junit.jupiter.api.Test;
+
+import java.lang.reflect.Field;
+import java.util.HashMap;
+import java.util.Map;
+import java.util.Queue;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+/**
+ * RingMessageManager unit test.
+ */
+public class RingMessageManagerTest {
+
+ @Test
+ public void testSendHeartbeatMessage() {
+ Instance instance1 = new RingInstance(null, 1, 1);
+ Map instanceMap = new HashMap<>();
+ instanceMap.put(1, instance1);
+ MessageManager messageManager = new RingMessageManager(instanceMap);
+ assertTrue(messageManager.sendHeartbeatMessage(1));
+ }
+
+ @Test
+ public void testSendElectionMessage() {
+ try {
+ Instance instance1 = new RingInstance(null, 1, 1);
+ Instance instance2 = new RingInstance(null, 1, 2);
+ Instance instance3 = new RingInstance(null, 1, 3);
+ Map instanceMap = new HashMap<>();
+ instanceMap.put(1, instance1);
+ instanceMap.put(2, instance2);
+ instanceMap.put(3, instance3);
+ MessageManager messageManager = new RingMessageManager(instanceMap);
+ String messageContent = "2";
+ messageManager.sendElectionMessage(2, messageContent);
+ Message ringMessage = new Message(MessageType.ELECTION, messageContent);
+ Class instanceClass = AbstractInstance.class;
+ Field messageQueueField = instanceClass.getDeclaredField("messageQueue");
+ messageQueueField.setAccessible(true);
+ Message ringMessageSent = ((Queue) messageQueueField.get(instance3)).poll();
+ assertEquals(ringMessageSent.getType(), ringMessage.getType());
+ assertEquals(ringMessageSent.getContent(), ringMessage.getContent());
+ } catch (NoSuchFieldException | IllegalAccessException e) {
+ fail("Error to access private field.");
+ }
+ }
+
+ @Test
+ public void testSendLeaderMessage() {
+ try {
+ Instance instance1 = new RingInstance(null, 1, 1);
+ Instance instance2 = new RingInstance(null, 1, 2);
+ Instance instance3 = new RingInstance(null, 1, 3);
+ Map instanceMap = new HashMap<>();
+ instanceMap.put(1, instance1);
+ instanceMap.put(2, instance2);
+ instanceMap.put(3, instance3);
+ MessageManager messageManager = new RingMessageManager(instanceMap);
+ String messageContent = "3";
+ messageManager.sendLeaderMessage(2, 3);
+ Message ringMessage = new Message(MessageType.LEADER, messageContent);
+ Class instanceClass = AbstractInstance.class;
+ Field messageQueueField = instanceClass.getDeclaredField("messageQueue");
+ messageQueueField.setAccessible(true);
+ Message ringMessageSent = ((Queue) messageQueueField.get(instance3)).poll();
+ assertEquals(ringMessageSent, ringMessage);
+ } catch (NoSuchFieldException | IllegalAccessException e) {
+ fail("Error to access private field.");
+ }
+ }
+
+ @Test
+ public void testSendHeartbeatInvokeMessage() {
+ try {
+ Instance instance1 = new RingInstance(null, 1, 1);
+ Instance instance2 = new RingInstance(null, 1, 2);
+ Instance instance3 = new RingInstance(null, 1, 3);
+ Map instanceMap = new HashMap<>();
+ instanceMap.put(1, instance1);
+ instanceMap.put(2, instance2);
+ instanceMap.put(3, instance3);
+ MessageManager messageManager = new RingMessageManager(instanceMap);
+ messageManager.sendHeartbeatInvokeMessage(2);
+ Message ringMessage = new Message(MessageType.HEARTBEAT_INVOKE, "");
+ Class instanceClass = AbstractInstance.class;
+ Field messageQueueField = instanceClass.getDeclaredField("messageQueue");
+ messageQueueField.setAccessible(true);
+ Message ringMessageSent = ((Queue) messageQueueField.get(instance3)).poll();
+ assertEquals(ringMessageSent.getType(), ringMessage.getType());
+ assertEquals(ringMessageSent.getContent(), ringMessage.getContent());
+ } catch (NoSuchFieldException | IllegalAccessException e) {
+ fail("Error to access private field.");
+ }
+ }
+
+}
diff --git a/pom.xml b/pom.xml
index 39cfee91c..d812d27c4 100644
--- a/pom.xml
+++ b/pom.xml
@@ -176,7 +176,9 @@
commander
typeobjectpattern
bytecode
+ leader-election
data-locality
+