diff --git a/api-gateway/api-gateway-service/src/main/java/com/iluwatar/api/gateway/ApiGateway.java b/api-gateway/api-gateway-service/src/main/java/com/iluwatar/api/gateway/ApiGateway.java
index 25c201521..18a071c09 100644
--- a/api-gateway/api-gateway-service/src/main/java/com/iluwatar/api/gateway/ApiGateway.java
+++ b/api-gateway/api-gateway-service/src/main/java/com/iluwatar/api/gateway/ApiGateway.java
@@ -23,12 +23,11 @@
package com.iluwatar.api.gateway;
+import javax.annotation.Resource;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RestController;
-import javax.annotation.Resource;
-
/**
* The ApiGateway aggregates calls to microservices based on the needs of the individual clients.
*/
@@ -42,7 +41,8 @@ public class ApiGateway {
private PriceClient priceClient;
/**
- * Retrieves product information that desktop clients need
+ * Retrieves product information that desktop clients need.
+ *
* @return Product information for clients on a desktop
*/
@RequestMapping(path = "/desktop", method = RequestMethod.GET)
@@ -54,7 +54,8 @@ public class ApiGateway {
}
/**
- * Retrieves product information that mobile clients need
+ * Retrieves product information that mobile clients need.
+ *
* @return Product information for clients on a mobile device
*/
@RequestMapping(path = "/mobile", method = RequestMethod.GET)
diff --git a/api-gateway/api-gateway-service/src/main/java/com/iluwatar/api/gateway/App.java b/api-gateway/api-gateway-service/src/main/java/com/iluwatar/api/gateway/App.java
index b92e3a7d0..1d72aaaec 100644
--- a/api-gateway/api-gateway-service/src/main/java/com/iluwatar/api/gateway/App.java
+++ b/api-gateway/api-gateway-service/src/main/java/com/iluwatar/api/gateway/App.java
@@ -27,39 +27,36 @@ import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
/**
- * With the Microservices pattern, a client may need data from multiple different microservices.
- * If the client called each microservice directly, that could contribute to longer load times,
- * since the client would have to make a network request for each microservice called. Moreover,
- * having the client call each microservice directly ties the client to that microservice - if the
- * internal implementations of the microservices change (for example, if two microservices are
- * combined sometime in the future) or if the location (host and port) of a microservice changes,
- * then every client that makes use of those microservices must be updated.
+ * With the Microservices pattern, a client may need data from multiple different microservices. If
+ * the client called each microservice directly, that could contribute to longer load times, since
+ * the client would have to make a network request for each microservice called. Moreover, having
+ * the client call each microservice directly ties the client to that microservice - if the internal
+ * implementations of the microservices change (for example, if two microservices are combined
+ * sometime in the future) or if the location (host and port) of a microservice changes, then every
+ * client that makes use of those microservices must be updated.
*
- *
- * The intent of the API Gateway pattern is to alleviate some of these issues. In the API Gateway
- * pattern, an additional entity (the API Gateway) is placed between the client and the
- * microservices. The job of the API Gateway is to aggregate the calls to the microservices.
- * Rather than the client calling each microservice individually, the client calls the API Gateway
- * a single time. The API Gateway then calls each of the microservices that the client needs.
+ *
The intent of the API Gateway pattern is to alleviate some of these issues. In the API
+ * Gateway pattern, an additional entity (the API Gateway) is placed between the client and the
+ * microservices. The job of the API Gateway is to aggregate the calls to the microservices. Rather
+ * than the client calling each microservice individually, the client calls the API Gateway a single
+ * time. The API Gateway then calls each of the microservices that the client needs.
*
- *
- * This implementation shows what the API Gateway pattern could look like for an e-commerce site.
- * The {@link ApiGateway} makes calls to the Image and Price microservices using the
- * {@link ImageClientImpl} and {@link PriceClientImpl} respectively. Customers viewing the site on a
- * desktop device can see both price information and an image of a product, so the {@link ApiGateway}
- * calls both of the microservices and aggregates the data in the {@link DesktopProduct} model.
- * However, mobile users only see price information; they do not see a product image. For mobile
- * users, the {@link ApiGateway} only retrieves price information, which it uses to populate the
- * {@link MobileProduct}.
+ *
This implementation shows what the API Gateway pattern could look like for an e-commerce
+ * site. The {@link ApiGateway} makes calls to the Image and Price microservices using the {@link
+ * ImageClientImpl} and {@link PriceClientImpl} respectively. Customers viewing the site on a
+ * desktop device can see both price information and an image of a product, so the {@link
+ * ApiGateway} calls both of the microservices and aggregates the data in the {@link DesktopProduct}
+ * model. However, mobile users only see price information; they do not see a product image. For
+ * mobile users, the {@link ApiGateway} only retrieves price information, which it uses to populate
+ * the {@link MobileProduct}.
*/
@SpringBootApplication
public class App {
/**
- * Program entry point
+ * Program entry point.
*
- * @param args
- * command line args
+ * @param args command line args
*/
public static void main(String[] args) {
SpringApplication.run(App.class, args);
diff --git a/api-gateway/api-gateway-service/src/main/java/com/iluwatar/api/gateway/DesktopProduct.java b/api-gateway/api-gateway-service/src/main/java/com/iluwatar/api/gateway/DesktopProduct.java
index 06b9e9495..2f790bef5 100644
--- a/api-gateway/api-gateway-service/src/main/java/com/iluwatar/api/gateway/DesktopProduct.java
+++ b/api-gateway/api-gateway-service/src/main/java/com/iluwatar/api/gateway/DesktopProduct.java
@@ -28,12 +28,12 @@ package com.iluwatar.api.gateway;
*/
public class DesktopProduct {
/**
- * The price of the product
+ * The price of the product.
*/
private String price;
/**
- * The path to the image of the product
+ * The path to the image of the product.
*/
private String imagePath;
diff --git a/api-gateway/api-gateway-service/src/main/java/com/iluwatar/api/gateway/ImageClient.java b/api-gateway/api-gateway-service/src/main/java/com/iluwatar/api/gateway/ImageClient.java
index 9c8c341cc..33e212b07 100644
--- a/api-gateway/api-gateway-service/src/main/java/com/iluwatar/api/gateway/ImageClient.java
+++ b/api-gateway/api-gateway-service/src/main/java/com/iluwatar/api/gateway/ImageClient.java
@@ -24,7 +24,7 @@
package com.iluwatar.api.gateway;
/**
- * An interface used to communicate with the Image microservice
+ * An interface used to communicate with the Image microservice.
*/
public interface ImageClient {
String getImagePath();
diff --git a/api-gateway/api-gateway-service/src/main/java/com/iluwatar/api/gateway/ImageClientImpl.java b/api-gateway/api-gateway-service/src/main/java/com/iluwatar/api/gateway/ImageClientImpl.java
index d2f80858c..6aa9698ef 100644
--- a/api-gateway/api-gateway-service/src/main/java/com/iluwatar/api/gateway/ImageClientImpl.java
+++ b/api-gateway/api-gateway-service/src/main/java/com/iluwatar/api/gateway/ImageClientImpl.java
@@ -29,17 +29,16 @@ import java.net.http.HttpClient;
import java.net.http.HttpRequest;
import java.net.http.HttpResponse;
import java.net.http.HttpResponse.BodyHandlers;
-
import org.springframework.stereotype.Component;
/**
- * An adapter to communicate with the Image microservice
+ * An adapter to communicate with the Image microservice.
*/
@Component
public class ImageClientImpl implements ImageClient {
/**
- * Makes a simple HTTP Get request to the Image microservice
- *
+ * Makes a simple HTTP Get request to the Image microservice.
+ *
* @return The path to the image
*/
@Override
@@ -47,7 +46,8 @@ public class ImageClientImpl implements ImageClient {
String response = null;
HttpClient httpClient = HttpClient.newHttpClient();
- HttpRequest httpGet = HttpRequest.newBuilder().GET().uri(URI.create("http://localhost:50005/image-path")).build();
+ HttpRequest httpGet =
+ HttpRequest.newBuilder().GET().uri(URI.create("http://localhost:50005/image-path")).build();
try {
HttpResponse httpResponse = httpClient.send(httpGet, BodyHandlers.ofString());
diff --git a/api-gateway/api-gateway-service/src/main/java/com/iluwatar/api/gateway/MobileProduct.java b/api-gateway/api-gateway-service/src/main/java/com/iluwatar/api/gateway/MobileProduct.java
index b7edb1047..45fa4e486 100644
--- a/api-gateway/api-gateway-service/src/main/java/com/iluwatar/api/gateway/MobileProduct.java
+++ b/api-gateway/api-gateway-service/src/main/java/com/iluwatar/api/gateway/MobileProduct.java
@@ -28,7 +28,7 @@ package com.iluwatar.api.gateway;
*/
public class MobileProduct {
/**
- * The price of the product
+ * The price of the product.
*/
private String price;
diff --git a/api-gateway/api-gateway-service/src/main/java/com/iluwatar/api/gateway/PriceClient.java b/api-gateway/api-gateway-service/src/main/java/com/iluwatar/api/gateway/PriceClient.java
index 74c564132..ebe5150ba 100644
--- a/api-gateway/api-gateway-service/src/main/java/com/iluwatar/api/gateway/PriceClient.java
+++ b/api-gateway/api-gateway-service/src/main/java/com/iluwatar/api/gateway/PriceClient.java
@@ -24,7 +24,7 @@
package com.iluwatar.api.gateway;
/**
- * An interface used to communicate with the Price microservice
+ * An interface used to communicate with the Price microservice.
*/
public interface PriceClient {
String getPrice();
diff --git a/api-gateway/api-gateway-service/src/main/java/com/iluwatar/api/gateway/PriceClientImpl.java b/api-gateway/api-gateway-service/src/main/java/com/iluwatar/api/gateway/PriceClientImpl.java
index 0a43c4b1f..0c63e57f4 100644
--- a/api-gateway/api-gateway-service/src/main/java/com/iluwatar/api/gateway/PriceClientImpl.java
+++ b/api-gateway/api-gateway-service/src/main/java/com/iluwatar/api/gateway/PriceClientImpl.java
@@ -29,17 +29,16 @@ import java.net.http.HttpClient;
import java.net.http.HttpRequest;
import java.net.http.HttpResponse;
import java.net.http.HttpResponse.BodyHandlers;
-
import org.springframework.stereotype.Component;
/**
- * An adapter to communicate with the Price microservice
+ * An adapter to communicate with the Price microservice.
*/
@Component
public class PriceClientImpl implements PriceClient {
/**
- * Makes a simple HTTP Get request to the Price microservice
- *
+ * Makes a simple HTTP Get request to the Price microservice.
+ *
* @return The price of the product
*/
@Override
@@ -48,7 +47,8 @@ public class PriceClientImpl implements PriceClient {
String response = null;
HttpClient httpClient = HttpClient.newHttpClient();
- HttpRequest httpGet = HttpRequest.newBuilder().GET().uri(URI.create("http://localhost:50006/price")).build();
+ HttpRequest httpGet =
+ HttpRequest.newBuilder().GET().uri(URI.create("http://localhost:50006/price")).build();
try {
HttpResponse httpResponse = httpClient.send(httpGet, BodyHandlers.ofString());
diff --git a/api-gateway/api-gateway-service/src/main/resources/application.properties b/api-gateway/api-gateway-service/src/main/resources/application.properties
index 35bbf3471..f9e29f5a7 100644
--- a/api-gateway/api-gateway-service/src/main/resources/application.properties
+++ b/api-gateway/api-gateway-service/src/main/resources/application.properties
@@ -20,5 +20,4 @@
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
# THE SOFTWARE.
#
-
server.port=50004
\ No newline at end of file
diff --git a/api-gateway/image-microservice/src/main/java/com/iluwatar/image/microservice/ImageApplication.java b/api-gateway/image-microservice/src/main/java/com/iluwatar/image/microservice/ImageApplication.java
index bb551ac31..12c001976 100644
--- a/api-gateway/image-microservice/src/main/java/com/iluwatar/image/microservice/ImageApplication.java
+++ b/api-gateway/image-microservice/src/main/java/com/iluwatar/image/microservice/ImageApplication.java
@@ -27,16 +27,16 @@ import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
/**
- * ImageApplication starts up Spring Boot, exposing endpoints for the Image microservice through
- * the {@link ImageController}.
+ * ImageApplication starts up Spring Boot, exposing endpoints for the Image microservice through the
+ * {@link ImageController}.
*/
@SpringBootApplication
public class ImageApplication {
/**
- * Microservice entry point
- * @param args
- * command line args
+ * Microservice entry point.
+ *
+ * @param args command line args
*/
public static void main(String[] args) {
SpringApplication.run(ImageApplication.class, args);
diff --git a/api-gateway/image-microservice/src/main/java/com/iluwatar/image/microservice/ImageController.java b/api-gateway/image-microservice/src/main/java/com/iluwatar/image/microservice/ImageController.java
index 9781dbc01..b1f6dd3f7 100644
--- a/api-gateway/image-microservice/src/main/java/com/iluwatar/image/microservice/ImageController.java
+++ b/api-gateway/image-microservice/src/main/java/com/iluwatar/image/microservice/ImageController.java
@@ -28,13 +28,14 @@ import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RestController;
/**
- * Exposes the Image microservice's endpoints
+ * Exposes the Image microservice's endpoints.
*/
@RestController
public class ImageController {
/**
- * An endpoint for a user to retrieve an image path
+ * An endpoint for a user to retrieve an image path.
+ *
* @return An image path
*/
@RequestMapping(value = "/image-path", method = RequestMethod.GET)
diff --git a/api-gateway/price-microservice/src/main/java/com/iluwatar/price/microservice/PriceApplication.java b/api-gateway/price-microservice/src/main/java/com/iluwatar/price/microservice/PriceApplication.java
index 1a29e53c9..5fc6a0f96 100644
--- a/api-gateway/price-microservice/src/main/java/com/iluwatar/price/microservice/PriceApplication.java
+++ b/api-gateway/price-microservice/src/main/java/com/iluwatar/price/microservice/PriceApplication.java
@@ -27,16 +27,16 @@ import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
/**
- * PriceApplication starts up Spring Boot, exposing endpoints for the Price microservice through
- * the {@link PriceController}.
+ * PriceApplication starts up Spring Boot, exposing endpoints for the Price microservice through the
+ * {@link PriceController}.
*/
@SpringBootApplication
public class PriceApplication {
/**
- * Microservice entry point
- * @param args
- * command line args
+ * Microservice entry point.
+ *
+ * @param args command line args
*/
public static void main(String[] args) {
SpringApplication.run(PriceApplication.class, args);
diff --git a/api-gateway/price-microservice/src/main/java/com/iluwatar/price/microservice/PriceController.java b/api-gateway/price-microservice/src/main/java/com/iluwatar/price/microservice/PriceController.java
index efb982253..cf2f5eb4f 100644
--- a/api-gateway/price-microservice/src/main/java/com/iluwatar/price/microservice/PriceController.java
+++ b/api-gateway/price-microservice/src/main/java/com/iluwatar/price/microservice/PriceController.java
@@ -28,13 +28,14 @@ import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RestController;
/**
- * Exposes the Price microservice's endpoints
+ * Exposes the Price microservice's endpoints.
*/
@RestController
public class PriceController {
/**
- * An endpoint for a user to retrieve a product's price
+ * An endpoint for a user to retrieve a product's price.
+ *
* @return A product's price
*/
@RequestMapping(value = "/price", method = RequestMethod.GET)
diff --git a/lazy-loading/src/main/java/com/iluwatar/lazy/loading/App.java b/lazy-loading/src/main/java/com/iluwatar/lazy/loading/App.java
index ec795b40f..ace157154 100644
--- a/lazy-loading/src/main/java/com/iluwatar/lazy/loading/App.java
+++ b/lazy-loading/src/main/java/com/iluwatar/lazy/loading/App.java
@@ -27,22 +27,20 @@ import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
- *
* Lazy loading idiom defers object creation until needed.
- *
- * This example shows different implementations of the pattern with increasing sophistication.
- *
- * Additional information and lazy loading flavours are described in
- * http://martinfowler.com/eaaCatalog/lazyLoad.html
*
+ *
This example shows different implementations of the pattern with increasing sophistication.
+ *
+ *
Additional information and lazy loading flavours are described in
+ * http://martinfowler.com/eaaCatalog/lazyLoad.html
*/
public class App {
private static final Logger LOGGER = LoggerFactory.getLogger(App.class);
/**
- * Program entry point
- *
+ * Program entry point.
+ *
* @param args command line args
*/
public static void main(String[] args) {
diff --git a/lazy-loading/src/main/java/com/iluwatar/lazy/loading/Heavy.java b/lazy-loading/src/main/java/com/iluwatar/lazy/loading/Heavy.java
index 1e2dd8ae7..dea2d6341 100644
--- a/lazy-loading/src/main/java/com/iluwatar/lazy/loading/Heavy.java
+++ b/lazy-loading/src/main/java/com/iluwatar/lazy/loading/Heavy.java
@@ -27,16 +27,14 @@ import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
- *
* Heavy objects are expensive to create.
- *
*/
public class Heavy {
private static final Logger LOGGER = LoggerFactory.getLogger(Heavy.class);
/**
- * Constructor
+ * Constructor.
*/
public Heavy() {
LOGGER.info("Creating Heavy ...");
diff --git a/lazy-loading/src/main/java/com/iluwatar/lazy/loading/HolderNaive.java b/lazy-loading/src/main/java/com/iluwatar/lazy/loading/HolderNaive.java
index a23f70fb7..c18ced6d4 100644
--- a/lazy-loading/src/main/java/com/iluwatar/lazy/loading/HolderNaive.java
+++ b/lazy-loading/src/main/java/com/iluwatar/lazy/loading/HolderNaive.java
@@ -27,9 +27,7 @@ import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
- *
* Simple implementation of the lazy loading idiom. However, this is not thread safe.
- *
*/
public class HolderNaive {
@@ -38,14 +36,14 @@ public class HolderNaive {
private Heavy heavy;
/**
- * Constructor
+ * Constructor.
*/
public HolderNaive() {
LOGGER.info("HolderNaive created");
}
/**
- * Get heavy object
+ * Get heavy object.
*/
public Heavy getHeavy() {
if (heavy == null) {
diff --git a/lazy-loading/src/main/java/com/iluwatar/lazy/loading/HolderThreadSafe.java b/lazy-loading/src/main/java/com/iluwatar/lazy/loading/HolderThreadSafe.java
index b7c72e14c..ef6d5e663 100644
--- a/lazy-loading/src/main/java/com/iluwatar/lazy/loading/HolderThreadSafe.java
+++ b/lazy-loading/src/main/java/com/iluwatar/lazy/loading/HolderThreadSafe.java
@@ -27,10 +27,8 @@ import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
- *
* Same as HolderNaive but with added synchronization. This implementation is thread safe, but each
* {@link #getHeavy()} call costs additional synchronization overhead.
- *
*/
public class HolderThreadSafe {
@@ -39,14 +37,14 @@ public class HolderThreadSafe {
private Heavy heavy;
/**
- * Constructor
+ * Constructor.
*/
public HolderThreadSafe() {
LOGGER.info("HolderThreadSafe created");
}
/**
- * Get heavy object
+ * Get heavy object.
*/
public synchronized Heavy getHeavy() {
if (heavy == null) {
diff --git a/lazy-loading/src/main/java/com/iluwatar/lazy/loading/Java8Holder.java b/lazy-loading/src/main/java/com/iluwatar/lazy/loading/Java8Holder.java
index 5066b5479..2854a7822 100644
--- a/lazy-loading/src/main/java/com/iluwatar/lazy/loading/Java8Holder.java
+++ b/lazy-loading/src/main/java/com/iluwatar/lazy/loading/Java8Holder.java
@@ -23,16 +23,13 @@
package com.iluwatar.lazy.loading;
+import java.util.function.Supplier;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
-import java.util.function.Supplier;
-
/**
- *
* This lazy loader is thread safe and more efficient than {@link HolderThreadSafe}. It utilizes
* Java 8 functional interface {@link Supplier} as {@link Heavy} factory.
- *
*/
public class Java8Holder {
@@ -57,9 +54,11 @@ public class Java8Holder {
return heavyInstance;
}
}
+
if (!HeavyFactory.class.isInstance(heavy)) {
heavy = new HeavyFactory();
}
+
return heavy.get();
}
}
diff --git a/leader-election/src/main/java/com/iluwatar/leaderelection/AbstractInstance.java b/leader-election/src/main/java/com/iluwatar/leaderelection/AbstractInstance.java
index d69a1f134..f30610597 100644
--- a/leader-election/src/main/java/com/iluwatar/leaderelection/AbstractInstance.java
+++ b/leader-election/src/main/java/com/iluwatar/leaderelection/AbstractInstance.java
@@ -23,11 +23,10 @@
package com.iluwatar.leaderelection;
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
-
import java.util.Queue;
import java.util.concurrent.ConcurrentLinkedQueue;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
/**
* Abstract class of all the instance implementation classes.
@@ -69,7 +68,9 @@ public abstract class AbstractInstance implements Instance, Runnable {
}
/**
- * Once messages are sent to the certain instance, it will firstly be added to the queue and wait to be executed.
+ * 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
@@ -79,6 +80,7 @@ public abstract class AbstractInstance implements Instance, Runnable {
/**
* Check if the instance is alive or not.
+ *
* @return {@code true} if the instance is alive.
*/
@Override
@@ -88,6 +90,7 @@ public abstract class AbstractInstance implements Instance, Runnable {
/**
* Set the health status of the certain instance.
+ *
* @param alive {@code true} for alive.
*/
@Override
@@ -97,6 +100,7 @@ public abstract class AbstractInstance implements Instance, Runnable {
/**
* Process the message according to its type.
+ *
* @param message Message polled from queue.
*/
private void processMessage(Message message) {
@@ -131,8 +135,8 @@ public abstract class AbstractInstance implements Instance, Runnable {
}
/**
- * Abstract methods to handle different types of message. These methods need to be implemented in concrete instance
- * class to implement corresponding leader-selection pattern.
+ * 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);
diff --git a/leader-election/src/main/java/com/iluwatar/leaderelection/AbstractMessageManager.java b/leader-election/src/main/java/com/iluwatar/leaderelection/AbstractMessageManager.java
index c7e4fa598..ae2c2f380 100644
--- a/leader-election/src/main/java/com/iluwatar/leaderelection/AbstractMessageManager.java
+++ b/leader-election/src/main/java/com/iluwatar/leaderelection/AbstractMessageManager.java
@@ -38,7 +38,7 @@ public abstract class AbstractMessageManager implements MessageManager {
protected Map instanceMap;
/**
- * Construtor of AbstractMessageManager
+ * Construtor of AbstractMessageManager.
*/
public AbstractMessageManager(Map instanceMap) {
this.instanceMap = instanceMap;
@@ -46,15 +46,16 @@ public abstract class AbstractMessageManager implements MessageManager {
/**
* 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());
+ .stream()
+ .filter((i) -> i > currentId && instanceMap.get(i).isAlive())
+ .sorted()
+ .collect(Collectors.toList());
if (candidateList.isEmpty()) {
int index = instanceMap.keySet()
.stream()
diff --git a/leader-election/src/main/java/com/iluwatar/leaderelection/Instance.java b/leader-election/src/main/java/com/iluwatar/leaderelection/Instance.java
index 1b39dff83..3ea57c04b 100644
--- a/leader-election/src/main/java/com/iluwatar/leaderelection/Instance.java
+++ b/leader-election/src/main/java/com/iluwatar/leaderelection/Instance.java
@@ -24,24 +24,27 @@
package com.iluwatar.leaderelection;
/**
- * Instance interface
+ * 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
index 1302d5588..21f021aff 100644
--- a/leader-election/src/main/java/com/iluwatar/leaderelection/Message.java
+++ b/leader-election/src/main/java/com/iluwatar/leaderelection/Message.java
@@ -26,7 +26,7 @@ package com.iluwatar.leaderelection;
import java.util.Objects;
/**
- * Message used to transport data between instances.
+ * Message used to transport data between instances.
*/
public class Message {
@@ -34,7 +34,8 @@ public class Message {
private String content;
- public Message() {}
+ public Message() {
+ }
public Message(MessageType type, String content) {
this.type = type;
diff --git a/leader-election/src/main/java/com/iluwatar/leaderelection/MessageManager.java b/leader-election/src/main/java/com/iluwatar/leaderelection/MessageManager.java
index fbd41cac9..9f10de22e 100644
--- a/leader-election/src/main/java/com/iluwatar/leaderelection/MessageManager.java
+++ b/leader-election/src/main/java/com/iluwatar/leaderelection/MessageManager.java
@@ -24,12 +24,13 @@
package com.iluwatar.leaderelection;
/**
- * MessageManager interface
+ * 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.
*/
@@ -37,22 +38,25 @@ public interface MessageManager {
/**
* Send election message to other instances.
+ *
* @param currentId Instance ID of which sends this message.
- * @param content Election message content.
+ * @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.
+ * @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
index 1749ca15c..a82bfa38f 100644
--- a/leader-election/src/main/java/com/iluwatar/leaderelection/MessageType.java
+++ b/leader-election/src/main/java/com/iluwatar/leaderelection/MessageType.java
@@ -24,7 +24,7 @@
package com.iluwatar.leaderelection;
/**
- * Message Type enum
+ * Message Type enum.
*/
public enum MessageType {
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
index c111f442e..34231b3d5 100644
--- a/leader-election/src/main/java/com/iluwatar/leaderelection/bully/BullyApp.java
+++ b/leader-election/src/main/java/com/iluwatar/leaderelection/bully/BullyApp.java
@@ -27,19 +27,18 @@ 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.
+ * 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
+ * Program entry point.
*/
public static void main(String[] args) {
@@ -60,11 +59,11 @@ public class BullyApp {
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);
+ final Thread thread1 = new Thread(instance1);
+ final Thread thread2 = new Thread(instance2);
+ final Thread thread3 = new Thread(instance3);
+ final Thread thread4 = new Thread(instance4);
+ final Thread thread5 = new Thread(instance5);
thread1.start();
thread2.start();
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
index c2c497339..92cb18ab4 100644
--- a/leader-election/src/main/java/com/iluwatar/leaderelection/bully/BullyInstance.java
+++ b/leader-election/src/main/java/com/iluwatar/leaderelection/bully/BullyInstance.java
@@ -32,11 +32,11 @@ 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.
+ * 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 {
@@ -50,9 +50,9 @@ public class BullyInstance extends AbstractInstance {
}
/**
- * 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.
+ * 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() {
@@ -64,7 +64,8 @@ public class BullyInstance extends AbstractInstance {
messageManager.sendHeartbeatInvokeMessage(localId);
} else {
LOGGER.info("Instance " + localId + "- Leader is not alive. Start election.");
- boolean electionResult = messageManager.sendElectionMessage(localId, String.valueOf(localId));
+ boolean electionResult =
+ messageManager.sendElectionMessage(localId, String.valueOf(localId));
if (electionResult) {
LOGGER.info("Instance " + localId + "- Succeed in election. Start leader notification.");
messageManager.sendLeaderMessage(localId, localId);
@@ -76,9 +77,9 @@ public class BullyInstance extends AbstractInstance {
}
/**
- * 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.
+ * 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() {
@@ -111,11 +112,14 @@ public class BullyInstance extends AbstractInstance {
* Not used in Bully instance.
*/
@Override
- protected void handleLeaderInvokeMessage() {}
+ protected void handleLeaderInvokeMessage() {
+ }
@Override
- protected void handleHeartbeatMessage(Message message) {}
+ protected void handleHeartbeatMessage(Message message) {
+ }
@Override
- protected void handleElectionMessage(Message message) {}
+ 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
index 907098f6b..d1e4c7db1 100644
--- a/leader-election/src/main/java/com/iluwatar/leaderelection/bully/BullyMessageManager.java
+++ b/leader-election/src/main/java/com/iluwatar/leaderelection/bully/BullyMessageManager.java
@@ -27,13 +27,12 @@ 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
+ * Implementation of BullyMessageManager.
*/
public class BullyMessageManager extends AbstractMessageManager {
@@ -46,6 +45,7 @@ public class BullyMessageManager extends AbstractMessageManager {
/**
* Send heartbeat message to current leader instance to check the health.
+ *
* @param leaderId leaderID
* @return {@code true} if the leader is alive.
*/
@@ -58,8 +58,9 @@ public class BullyMessageManager extends AbstractMessageManager {
/**
* Send election message to all the instances with smaller ID.
+ *
* @param currentId Instance ID of which sends this message.
- * @param content Election message content.
+ * @param content Election message content.
* @return {@code true} if no alive instance has smaller ID, so that the election is accepted.
*/
@Override
@@ -70,29 +71,31 @@ public class BullyMessageManager extends AbstractMessageManager {
} else {
Message electionMessage = new Message(MessageType.ELECTION_INVOKE, "");
candidateList.stream()
- .forEach((i) -> instanceMap.get(i).onMessage(electionMessage));
+ .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.
+ * @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));
+ .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
@@ -104,14 +107,15 @@ public class BullyMessageManager extends AbstractMessageManager {
/**
* 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());
+ .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
index a8a6271ea..096beb566 100644
--- a/leader-election/src/main/java/com/iluwatar/leaderelection/ring/RingApp.java
+++ b/leader-election/src/main/java/com/iluwatar/leaderelection/ring/RingApp.java
@@ -27,19 +27,18 @@ 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.
+ * 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
+ * Program entry point.
*/
public static void main(String[] args) {
@@ -60,11 +59,11 @@ public class RingApp {
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);
+ final Thread thread1 = new Thread(instance1);
+ final Thread thread2 = new Thread(instance2);
+ final Thread thread3 = new Thread(instance3);
+ final Thread thread4 = new Thread(instance4);
+ final Thread thread5 = new Thread(instance5);
thread1.start();
thread2.start();
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
index 4cdbb5709..903ac15ce 100644
--- a/leader-election/src/main/java/com/iluwatar/leaderelection/ring/RingInstance.java
+++ b/leader-election/src/main/java/com/iluwatar/leaderelection/ring/RingInstance.java
@@ -26,23 +26,22 @@ 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;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
/**
* 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.
+ * 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 {
@@ -56,9 +55,9 @@ public class RingInstance extends AbstractInstance {
}
/**
- * 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.
+ * 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() {
@@ -78,9 +77,10 @@ public class RingInstance extends AbstractInstance {
}
/**
- * 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.
+ * 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) {
@@ -88,9 +88,9 @@ public class RingInstance extends AbstractInstance {
LOGGER.info("Instance " + localId + " - Election Message: " + content);
List candidateList =
Arrays.stream(content.trim().split(","))
- .map(Integer::valueOf)
- .sorted()
- .collect(Collectors.toList());
+ .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 + ".");
@@ -102,8 +102,8 @@ public class RingInstance extends AbstractInstance {
}
/**
- * 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.
+ * 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) {
@@ -122,12 +122,15 @@ public class RingInstance extends AbstractInstance {
* Not used in Ring instance.
*/
@Override
- protected void handleLeaderInvokeMessage() {}
+ protected void handleLeaderInvokeMessage() {
+ }
@Override
- protected void handleHeartbeatMessage(Message message) {}
+ protected void handleHeartbeatMessage(Message message) {
+ }
@Override
- protected void handleElectionInvokeMessage() {}
+ 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
index 344963633..6cbadf184 100644
--- a/leader-election/src/main/java/com/iluwatar/leaderelection/ring/RingMessageManager.java
+++ b/leader-election/src/main/java/com/iluwatar/leaderelection/ring/RingMessageManager.java
@@ -27,11 +27,10 @@ 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
+ * Implementation of RingMessageManager.
*/
public class RingMessageManager extends AbstractMessageManager {
@@ -44,6 +43,7 @@ public class RingMessageManager extends AbstractMessageManager {
/**
* Send heartbeat message to current leader instance to check the health.
+ *
* @param leaderId leaderID
* @return {@code true} if the leader is alive.
*/
@@ -56,8 +56,10 @@ public class RingMessageManager extends AbstractMessageManager {
/**
* 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.
+ * @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
@@ -70,8 +72,9 @@ public class RingMessageManager extends AbstractMessageManager {
/**
* Send leader message to the next instance.
+ *
* @param currentId Instance ID of which sends this message.
- * @param leaderId Leader message content.
+ * @param leaderId Leader message content.
* @return {@code true} if the leader message is accepted by the target instance.
*/
@Override
@@ -84,6 +87,7 @@ public class RingMessageManager extends AbstractMessageManager {
/**
* Send heartbeat invoke message to the next instance.
+ *
* @param currentId Instance ID of which sends this message.
*/
@Override