added test coverage for app.java and fixed random to be thread safe #2973

Author: skamble2

rate-limiting-pattern/src/main/java/com/iluwatar/rate/limiting/pattern/App.java

@@ -1,10 +1,10 @@
 package com.iluwatar.rate.limiting.pattern;
 
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
 import java.util.concurrent.*;
 import java.util.concurrent.atomic.AtomicBoolean;
 import java.util.concurrent.atomic.AtomicInteger;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 
 /**
  * The <em>Rate Limiter</em> pattern is a key defensive strategy used to prevent system overload and
@@ -99,10 +99,13 @@ private static void shutdownExecutor(ExecutorService service, String name) {
     }
   }
 
-  static Runnable createClientTask(int clientId, RateLimiter s3Limiter, RateLimiter dynamoDbLimiter, RateLimiter lambdaLimiter) {
+  static Runnable createClientTask(
+      int clientId, RateLimiter s3Limiter, RateLimiter dynamoDbLimiter, RateLimiter lambdaLimiter) {
     return () -> {
       String[] services = {"s3", "dynamodb", "lambda"};
-      String[] operations = {"GetObject", "PutObject", "Query", "Scan", "PutItem", "Invoke", "ListFunctions"};
+      String[] operations = {
+        "GetObject", "PutObject", "Query", "Scan", "PutItem", "Invoke", "ListFunctions"
+      };
       ThreadLocalRandom random = ThreadLocalRandom.current();
 
       while (running.get() && !Thread.currentThread().isInterrupted()) {
@@ -132,7 +135,12 @@ static void makeRequest(int clientId, RateLimiter limiter, String service, Strin
       LOGGER.info("Client {}: {}.{} - ALLOWED", clientId, service, operation);
     } catch (ThrottlingException e) {
       throttledRequests.incrementAndGet();
-      LOGGER.warn("Client {}: {}.{} - THROTTLED (Retry in {}ms)", clientId, service, operation, e.getRetryAfterMillis());
+      LOGGER.warn(
+          "Client {}: {}.{} - THROTTLED (Retry in {}ms)",
+          clientId,
+          service,
+          operation,
+          e.getRetryAfterMillis());
     } catch (ServiceUnavailableException e) {
       failedRequests.incrementAndGet();
       LOGGER.warn("Client {}: {}.{} - SERVICE UNAVAILABLE", clientId, service, operation);

rate-limiting-pattern/src/test/java/com/iluwatar/rate/limiting/pattern/AppTest.java

@@ -6,9 +6,7 @@
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 
-/**
- * Unit tests for {@link App}.
- */
+/** Unit tests for {@link App}. */
 class AppTest {
 
   private RateLimiter mockLimiter;

rate-limiting-pattern/src/test/java/com/iluwatar/rate/limiting/pattern/AppTestUtils.java

@@ -4,7 +4,8 @@
 
 public class AppTestUtils {
 
-  public static void invokeMakeRequest(int clientId, RateLimiter limiter, String service, String operation) {
+  public static void invokeMakeRequest(
+      int clientId, RateLimiter limiter, String service, String operation) {
     App.makeRequest(clientId, limiter, service, operation);
   }
 

rate-limiting-pattern/src/test/java/com/iluwatar/rate/limiting/pattern/FindCustomerRequestTest.java

@@ -48,13 +48,14 @@ void shouldExecuteUsingDefaultHelper() throws Exception {
   void shouldThrowServiceUnavailableOnInterruptedException() {
     RateLimiter noOpLimiter = (service, operation) -> {}; // no throttling
 
-    FindCustomerRequest request = new FindCustomerRequest("999", noOpLimiter) {
-      @Override
-      public String execute() throws RateLimitException {
-        Thread.currentThread().interrupt(); // Simulate thread interruption
-        return super.execute(); // Should throw ServiceUnavailableException
-      }
-    };
+    FindCustomerRequest request =
+        new FindCustomerRequest("999", noOpLimiter) {
+          @Override
+          public String execute() throws RateLimitException {
+            Thread.currentThread().interrupt(); // Simulate thread interruption
+            return super.execute(); // Should throw ServiceUnavailableException
+          }
+        };
 
     assertThrows(ServiceUnavailableException.class, request::execute);
   }