feat: Implement Spring Cache for Account Service Transaction Retrieval

Account-Service/pom.xml

@@ -42,6 +42,14 @@
             <groupId>org.springframework.cloud</groupId>
             <artifactId>spring-cloud-starter-openfeign</artifactId>
         </dependency>
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter-cache</artifactId>
+        </dependency>
+        <dependency>
+            <groupId>com.github.ben-manes.caffeine</groupId>
+            <artifactId>caffeine</artifactId>
+        </dependency>
 
         <dependency>
             <groupId>org.springframework.boot</groupId>
@@ -64,6 +72,11 @@
             <artifactId>spring-boot-starter-test</artifactId>
             <scope>test</scope>
         </dependency>
+        <dependency>
+            <groupId>com.h2database</groupId>
+            <artifactId>h2</artifactId>
+            <scope>runtime</scope>
+        </dependency>
     </dependencies>
     <dependencyManagement>
         <dependencies>

Account-Service/src/main/java/org/training/account/service/AccountServiceApplication.java

@@ -2,10 +2,12 @@
 
 import org.springframework.boot.SpringApplication;
 import org.springframework.boot.autoconfigure.SpringBootApplication;
+import org.springframework.cache.annotation.EnableCaching;
 import org.springframework.cloud.openfeign.EnableFeignClients;
 
 @SpringBootApplication
 @EnableFeignClients
+@EnableCaching
 public class AccountServiceApplication {
 
     public static void main(String[] args) {

Account-Service/src/main/java/org/training/account/service/external/TransactionService.java

@@ -8,7 +8,7 @@
 
 import java.util.List;
 
-@FeignClient(name = "transaction-service", configuration = FeignConfiguration.class)
+@FeignClient(name = "transaction-service", url = "http://localhost:8082", configuration = FeignConfiguration.class)
 public interface TransactionService {
 
     /**

Account-Service/src/main/java/org/training/account/service/service/implementation/AccountServiceImpl.java

@@ -4,6 +4,7 @@
 import lombok.extern.slf4j.Slf4j;
 import org.springframework.beans.BeanUtils;
 import org.springframework.beans.factory.annotation.Value;
+import org.springframework.cache.annotation.Cacheable;
 import org.springframework.http.ResponseEntity;
 import org.springframework.stereotype.Service;
 import org.training.account.service.exception.*;
@@ -162,6 +163,7 @@ public String getBalance(String accountNumber) {
      * @return A list of transaction responses
      */
     @Override
+    @Cacheable(value = "transactions", key = "#accountId")
     public List<TransactionResponse> getTransactionsFromAccountId(String accountId) {
 
         return transactionService.getTransactionsFromAccountId(accountId);
@@ -213,4 +215,4 @@ public AccountDto readAccountByUserId(Long userId) {
                     return accountDto;
                 }).orElseThrow(ResourceNotFound::new);
     }
-}
+}

Account-Service/src/main/resources/application.yml

@@ -7,17 +7,30 @@ spring:
     not_found: 404
 
   datasource:
-    url: jdbc:mysql://localhost:3306/account_service
-    username: root
-    password: root
+    url: jdbc:h2:mem:testdb
+    driver-class-name: org.h2.Driver
+    username: sa
+    password: password
 
   jpa:
+    database-platform: org.hibernate.dialect.H2Dialect
     hibernate:
-      ddl-auto: update
-    show-sql: true
-    properties:
-      hibernate:
-        format_sql: true
+      ddl-auto: create-drop
+    show-sql: false
+
+  cache:
+    type: caffeine
+    caffeine:
+      spec: maximumSize=1000,expireAfterWrite=5m
+    cache-names:
+      - transactions
 
 server:
   port: 8081
+
+# Direct URL configuration for Feign clients
+feign:
+  client:
+    config:
+      transaction-service:
+        url: http://localhost:8082

Account-Service/src/test/java/org/training/account/service/CachePerformanceTest.java

@@ -0,0 +1,91 @@
+package org.training.account.service;
+
+import org.junit.jupiter.api.Test;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.boot.test.mock.mockito.MockBean;
+import org.springframework.test.context.ActiveProfiles;
+import org.training.account.service.external.TransactionService;
+import org.training.account.service.model.dto.external.TransactionResponse;
+import org.training.account.service.service.AccountService;
+
+import java.math.BigDecimal;
+import java.time.LocalDateTime;
+import java.util.Arrays;
+import java.util.List;
+
+import static org.mockito.ArgumentMatchers.anyString;
+import static org.mockito.Mockito.when;
+
+@SpringBootTest
+@ActiveProfiles("test")
+public class CachePerformanceTest {
+
+    @Autowired
+    private AccountService accountService;
+
+    @MockBean
+    private TransactionService transactionService;
+
+    @Test
+    public void testTransactionCachePerformance() {
+        String testAccountId = "TEST_ACCOUNT_001";
+
+        List<TransactionResponse> mockTransactions = Arrays.asList(
+            TransactionResponse.builder()
+                .referenceId("TXN001")
+                .accountId(testAccountId)
+                .transactionType("DEPOSIT")
+                .amount(BigDecimal.valueOf(1000))
+                .localDateTime(LocalDateTime.now())
+                .transactionStatus("COMPLETED")
+                .comments("Test transaction")
+                .build()
+        );
+
+        when(transactionService.getTransactionsFromAccountId(anyString()))
+            .thenAnswer(invocation -> {
+                Thread.sleep(100);
+                return mockTransactions;
+            });
+
+        System.out.println("=== Cache Performance Test ===");
+
+        long startTime1 = System.currentTimeMillis();
+        List<TransactionResponse> transactions1 = accountService.getTransactionsFromAccountId(testAccountId);
+        long endTime1 = System.currentTimeMillis();
+        long firstCallTime = endTime1 - startTime1;
+
+        System.out.println("First call (cache miss): " + firstCallTime + "ms");
+        System.out.println("Transactions found: " + (transactions1 != null ? transactions1.size() : 0));
+
+        long startTime2 = System.currentTimeMillis();
+        List<TransactionResponse> transactions2 = accountService.getTransactionsFromAccountId(testAccountId);
+        long endTime2 = System.currentTimeMillis();
+        long secondCallTime = endTime2 - startTime2;
+
+        System.out.println("Second call (cache hit): " + secondCallTime + "ms");
+        System.out.println("Transactions found: " + (transactions2 != null ? transactions2.size() : 0));
+
+        if (firstCallTime > 0) {
+            double improvement = ((double)(firstCallTime - secondCallTime) / firstCallTime) * 100;
+            System.out.println("Performance improvement: " + String.format("%.1f", improvement) + "%");
+
+            if (improvement > 90) {
+                System.out.println("✅ Cache performance target achieved (>90% improvement)");
+            } else if (improvement > 50) {
+                System.out.println("⚠️ Cache working but improvement below target (<90%)");
+            } else {
+                System.out.println("❌ Cache may not be working effectively");
+            }
+        }
+
+        long startTime3 = System.currentTimeMillis();
+        List<TransactionResponse> transactions3 = accountService.getTransactionsFromAccountId(testAccountId);
+        long endTime3 = System.currentTimeMillis();
+        long thirdCallTime = endTime3 - startTime3;
+
+        System.out.println("Third call (cache hit): " + thirdCallTime + "ms");
+        System.out.println("=== Test Complete ===");
+    }
+}

Account-Service/src/test/resources/application-test.yml

@@ -0,0 +1,39 @@
+spring:
+  application:
+    name: account-service-test
+    ok: 200
+    not_found: 404
+    bad_request: 400
+    conflict: 409
+
+  datasource:
+    url: jdbc:h2:mem:testdb
+    driver-class-name: org.h2.Driver
+    username: sa
+    password: password
+
+  jpa:
+    database-platform: org.hibernate.dialect.H2Dialect
+    hibernate:
+      ddl-auto: create-drop
+    show-sql: false
+
+  cache:
+    type: caffeine
+    caffeine:
+      spec: maximumSize=100,expireAfterWrite=1m
+    cache-names:
+      - transactions
+
+# Mock external services for testing
+feign:
+  client:
+    config:
+      default:
+        connectTimeout: 5000
+        readTimeout: 5000
+
+logging:
+  level:
+    org.training.account.service: DEBUG
+    org.springframework.cache: DEBUG

test-cache-performance.sh

@@ -0,0 +1,68 @@
+#!/bin/bash
+
+echo "=== Cache Performance Testing Script ==="
+echo "This script will test the cache implementation by making HTTP requests"
+echo
+
+ACCOUNT_ID="ACC0000001"
+BASE_URL="http://localhost:8081"
+ENDPOINT="/accounts/${ACCOUNT_ID}/transactions"
+
+echo "Testing endpoint: ${BASE_URL}${ENDPOINT}"
+echo
+
+make_request() {
+    local request_num=$1
+    echo "Request #${request_num}:"
+
+    start_time=$(date +%s%3N)
+    response=$(curl -s -w "%{http_code}" -o /tmp/response_${request_num}.json "${BASE_URL}${ENDPOINT}")
+    end_time=$(date +%s%3N)
+
+    duration=$((end_time - start_time))
+
+    if [ "$response" = "200" ]; then
+        transaction_count=$(cat /tmp/response_${request_num}.json | jq '. | length' 2>/dev/null || echo "unknown")
+        echo "  ✅ Success (${duration}ms) - Transactions: ${transaction_count}"
+    else
+        echo "  ❌ Failed (HTTP ${response}) - Time: ${duration}ms"
+    fi
+
+    echo "  Response time: ${duration}ms"
+    return $duration
+}
+
+echo "Making 5 consecutive requests to test cache performance..."
+echo
+
+times=()
+for i in {1..5}; do
+    make_request $i
+    times+=($?)
+    echo
+    sleep 1
+done
+
+echo "=== Performance Analysis ==="
+echo "Request times: ${times[@]}ms"
+
+if [ ${#times[@]} -ge 2 ]; then
+    first_time=${times[0]}
+    second_time=${times[1]}
+
+    if [ $first_time -gt 0 ]; then
+        improvement=$(( (first_time - second_time) * 100 / first_time ))
+        echo "Performance improvement from 1st to 2nd request: ${improvement}%"
+
+        if [ $improvement -gt 90 ]; then
+            echo "✅ Cache performance target achieved (>90% improvement)"
+        elif [ $improvement -gt 50 ]; then
+            echo "⚠️ Cache working but improvement below target"
+        else
+            echo "❌ Cache may not be working effectively"
+        fi
+    fi
+fi
+
+echo
+echo "=== Test Complete ==="