Resolves checkstyle errors for api-gateway, lazy-loading, leader-elec…

…tion (iluwatar#1066)

* Reduces checkstyle errors in lazy-loading

* Reduces checkstyle errors in leader-election

* Reduces checkstyle errors in api-gateway

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 DesktopProduct getProductDesktop() {
   }
 
   /**
-   * 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)

api-gateway/api-gateway-service/src/main/java/com/iluwatar/api/gateway/App.java

@@ -27,39 +27,36 @@
 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.
  *
- * <p>
- * 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.
+ * <p>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.
  *
- * <p>
- * 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}.
+ * <p>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);

api-gateway/api-gateway-service/src/main/java/com/iluwatar/api/gateway/DesktopProduct.java

@@ -28,12 +28,12 @@
  */
 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;
 

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();

api-gateway/api-gateway-service/src/main/java/com/iluwatar/api/gateway/ImageClientImpl.java

@@ -29,25 +29,25 @@
 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
   public String getImagePath() {
     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<String> httpResponse = httpClient.send(httpGet, BodyHandlers.ofString());

api-gateway/api-gateway-service/src/main/java/com/iluwatar/api/gateway/MobileProduct.java

@@ -28,7 +28,7 @@
  */
 public class MobileProduct {
   /**
-   * The price of the product
+   * The price of the product.
    */
   private String price;
 

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();

api-gateway/api-gateway-service/src/main/java/com/iluwatar/api/gateway/PriceClientImpl.java

@@ -29,17 +29,16 @@
 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 String getPrice() {
     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<String> httpResponse = httpClient.send(httpGet, BodyHandlers.ofString());

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

api-gateway/image-microservice/src/main/java/com/iluwatar/image/microservice/ImageApplication.java

@@ -27,16 +27,16 @@
 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);

api-gateway/image-microservice/src/main/java/com/iluwatar/image/microservice/ImageController.java

@@ -28,13 +28,14 @@
 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)

api-gateway/price-microservice/src/main/java/com/iluwatar/price/microservice/PriceApplication.java

@@ -27,16 +27,16 @@
 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);

api-gateway/price-microservice/src/main/java/com/iluwatar/price/microservice/PriceController.java

@@ -28,13 +28,14 @@
 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)

lazy-loading/src/main/java/com/iluwatar/lazy/loading/App.java

@@ -27,22 +27,20 @@
 import org.slf4j.LoggerFactory;
 
 /**
- * 
  * Lazy loading idiom defers object creation until needed.
- * <p>
- * This example shows different implementations of the pattern with increasing sophistication.
- * <p>
- * Additional information and lazy loading flavours are described in
- * http://martinfowler.com/eaaCatalog/lazyLoad.html
  *
+ * <p>This example shows different implementations of the pattern with increasing sophistication.
+ *
+ * <p>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) {

lazy-loading/src/main/java/com/iluwatar/lazy/loading/Heavy.java

@@ -27,16 +27,14 @@
 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 ...");

lazy-loading/src/main/java/com/iluwatar/lazy/loading/HolderNaive.java

@@ -27,9 +27,7 @@
 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) {

lazy-loading/src/main/java/com/iluwatar/lazy/loading/HolderThreadSafe.java

@@ -27,10 +27,8 @@
 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) {