Introduce caching with Caffeine and annotate EmployeeService with cache operations

pom.xml

@@ -52,6 +52,14 @@
             <groupId>org.springframework.boot</groupId>
             <artifactId>spring-boot-starter-web</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.apache.tika</groupId>
             <artifactId>tika-core</artifactId>

src/main/java/org/example/projektarendehantering/application/service/EmployeeService.java

@@ -10,6 +10,8 @@
 import org.example.projektarendehantering.presentation.dto.EmployeeCreateDTO;
 import org.example.projektarendehantering.presentation.dto.EmployeeDTO;
 import org.example.projektarendehantering.presentation.dto.EmployeeUpdateDTO;
+import org.springframework.cache.annotation.CacheEvict;
+import org.springframework.cache.annotation.Cacheable;
 import org.springframework.stereotype.Service;
 import org.springframework.transaction.annotation.Transactional;
 import lombok.RequiredArgsConstructor;
@@ -28,6 +30,7 @@ public class EmployeeService {
     private final EmployeeRepository employeeRepository;
     private final EmployeeMapper employeeMapper;
 
+    @CacheEvict(value = {"employees-by-role", "all-employees"}, allEntries = true)
     @Transactional
     public EmployeeDTO createEmployee(Actor actor, EmployeeCreateDTO dto) {
         requireCanManageEmployees(actor);
@@ -50,6 +53,7 @@ public EmployeeDTO createEmployee(Actor actor, EmployeeCreateDTO dto) {
         return employeeMapper.toDTO(employeeRepository.save(entity));
     }
 
+    @CacheEvict(value = {"employees-by-role", "all-employees"}, allEntries = true)
     @Transactional
     public EmployeeDTO updateEmployee(Actor actor, UUID id, EmployeeUpdateDTO dto) {
         requireCanManageEmployees(actor);
@@ -66,6 +70,7 @@ public EmployeeDTO updateEmployee(Actor actor, UUID id, EmployeeUpdateDTO dto) {
         return employeeMapper.toDTO(employeeRepository.save(entity));
     }
 
+    @CacheEvict(value = {"employees-by-role", "all-employees"}, allEntries = true)
     @Transactional
     public void deleteEmployee(Actor actor, UUID id) {
         requireCanManageEmployees(actor);
@@ -80,6 +85,7 @@ public Optional<EmployeeDTO> getEmployee(Actor actor, UUID id) {
         return employeeRepository.findById(id).map(employeeMapper::toDTO);
     }
 
+    @Cacheable("all-employees")
     @Transactional(readOnly = true)
     public List<EmployeeDTO> getAllEmployees(Actor actor) {
         requireCanManageEmployees(actor);
@@ -88,6 +94,7 @@ public List<EmployeeDTO> getAllEmployees(Actor actor) {
                 .collect(Collectors.toList());
     }
 
+    @Cacheable(value = "employees-by-role", key = "#role")
     @Transactional(readOnly = true)
     public List<EmployeeDTO> findByRole(Role role) {
         return employeeRepository.findAllByRole(role).stream()

src/main/java/org/example/projektarendehantering/infrastructure/config/CacheConfig.java

@@ -0,0 +1,23 @@
+package org.example.projektarendehantering.infrastructure.config;
+
+import com.github.benmanes.caffeine.cache.Caffeine;
+import org.springframework.cache.annotation.EnableCaching;
+import org.springframework.cache.caffeine.CaffeineCacheManager;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+
+import java.util.concurrent.TimeUnit;
+
+@Configuration
+@EnableCaching
+public class CacheConfig {
+
+    @Bean
+    public CaffeineCacheManager cacheManager() {
+        CaffeineCacheManager manager = new CaffeineCacheManager("employees-by-role", "all-employees");
+        manager.setCaffeine(Caffeine.newBuilder()
+                .maximumSize(500)
+                .expireAfterWrite(10, TimeUnit.MINUTES));
+        return manager;
+    }
+}