Switch from `EntityManager` to `EntityManagerFactory` across repositories, managers, and services for improved resource management and thread safety.

src/main/java/com/mediamanager/MediaManagerApplication.java

@@ -60,7 +60,7 @@ public class MediaManagerApplication {
                 default:
             }
             databaseManager.init();
-            actionManager = new DelegateActionManager(databaseManager.getEntityManager());
+            actionManager = new DelegateActionManager(databaseManager.getEntityManagerFactory());
             actionManager.start();
             ipcManager = new IPCManager(config,actionManager);
             ipcManager.init();

src/main/java/com/mediamanager/repository/GenreRepository.java

@@ -2,6 +2,7 @@ package com.mediamanager.repository;
 
 import com.mediamanager.model.Genre;
 import jakarta.persistence.EntityManager;
+import jakarta.persistence.EntityManagerFactory;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 
@@ -15,10 +16,10 @@ import java.util.Optional;
 public class GenreRepository {
     private static final Logger logger = LogManager.getLogger(GenreRepository.class);
 
-    private final EntityManager entityManager;
+    private final EntityManagerFactory entityManagerFactory;
 
-    public GenreRepository(EntityManager entityManager) {
+    public GenreRepository(EntityManagerFactory entityManagerFactory) {
-        this.entityManager = entityManager;
+        this.entityManagerFactory = entityManagerFactory;
     }
 
     /**
@@ -26,16 +27,19 @@ public class GenreRepository {
      */
     public Genre save(Genre genre) {
         logger.debug("Saving genre: {}", genre.getName());
-        entityManager.getTransaction().begin();
+        EntityManager em = entityManagerFactory.createEntityManager();
+        em.getTransaction().begin();
         try {
-            entityManager.persist(genre);
+            em.persist(genre);
-            entityManager.getTransaction().commit();
+            em.getTransaction().commit();
             logger.debug("Genre saved with ID: {}", genre.getId());
             return genre;
         } catch (Exception e) {
-            entityManager.getTransaction().rollback();
+            em.getTransaction().rollback();
             logger.error("Error saving genre", e);
             throw e;
+        } finally {
+            if (em.isOpen()) em.close();
         }
     }
 
@@ -44,9 +48,14 @@ public class GenreRepository {
      */
     public List<Genre> findAll() {
         logger.debug("Finding all genres");
-        return entityManager
+        EntityManager em = entityManagerFactory.createEntityManager();
-                .createQuery("SELECT g FROM Genre g ORDER BY g.name", Genre.class)
+        try {
-                .getResultList();
+            return em
+                    .createQuery("SELECT g FROM Genre g ORDER BY g.name", Genre.class)
+                    .getResultList();
+        } finally {
+            if (em.isOpen()) em.close();
+        }
     }
 
     /**
@@ -54,8 +63,13 @@ public class GenreRepository {
      */
     public Optional<Genre> findById(Integer id) {
         logger.debug("Finding genre by ID: {}", id);
-        Genre genre = entityManager.find(Genre.class, id);
+        EntityManager em = entityManagerFactory.createEntityManager();
-        return Optional.ofNullable(genre);
+        try {
+            Genre genre = em.find(Genre.class, id);
+            return Optional.ofNullable(genre);
+        } finally {
+            if (em.isOpen()) em.close();
+        }
     }
 
     /**
@@ -63,16 +77,19 @@ public class GenreRepository {
      */
     public Genre update(Genre genre) {
         logger.debug("Updating genre ID: {}", genre.getId());
-        entityManager.getTransaction().begin();
+        EntityManager em = entityManagerFactory.createEntityManager();
+        em.getTransaction().begin();
         try {
-            Genre updated = entityManager.merge(genre);
+            Genre updated = em.merge(genre);
-            entityManager.getTransaction().commit();
+            em.getTransaction().commit();
             logger.debug("Genre updated successfully");
             return updated;
         } catch (Exception e) {
-            entityManager.getTransaction().rollback();
+            em.getTransaction().rollback();
             logger.error("Error updating genre", e);
             throw e;
+        } finally {
+            if (em.isOpen()) em.close();
         }
     }
 
@@ -81,21 +98,24 @@ public class GenreRepository {
      */
     public boolean deleteById(Integer id) {
         logger.debug("Deleting genre by ID: {}", id);
-        entityManager.getTransaction().begin();
+        EntityManager em = entityManagerFactory.createEntityManager();
+        em.getTransaction().begin();
         try {
-            Genre genre = entityManager.find(Genre.class, id);
+            Genre genre = em.find(Genre.class, id);
             if (genre == null) {
-                entityManager.getTransaction().rollback();
+                em.getTransaction().rollback();
                 return false;
             }
-            entityManager.remove(genre);
+            em.remove(genre);
-            entityManager.getTransaction().commit();
+            em.getTransaction().commit();
             logger.debug("Genre deleted successfully");
             return true;
         } catch (Exception e) {
-            entityManager.getTransaction().rollback();
+            em.getTransaction().rollback();
             logger.error("Error deleting genre", e);
             throw e;
+        } finally {
+            if (em.isOpen()) em.close();
         }
     }
 }

src/main/java/com/mediamanager/service/database/DatabaseManager.java

@@ -1,6 +1,5 @@
 package com.mediamanager.service.database;
 
-import jakarta.persistence.EntityManager;
 import jakarta.persistence.EntityManagerFactory;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
@@ -20,7 +19,6 @@ public abstract class DatabaseManager {
     protected Connection connection;
     protected String connectionUrl;
     protected EntityManagerFactory entityManagerFactory;
-    protected EntityManager entityManager;
     protected static final Logger logger = LogManager.getLogger(DatabaseManager.class);
 
     public DatabaseManager(Properties config) {
@@ -48,14 +46,6 @@ public abstract class DatabaseManager {
     }
 
     public void close() {
-        if (entityManager != null && entityManager.isOpen()) {
-            try {
-                entityManager.close();
-                logger.info("EntityManager closed");
-            } catch (Exception e) {
-                logger.error("Error closing EntityManager: {}", e.getMessage());
-            }
-        }
         if (entityManagerFactory != null && entityManagerFactory.isOpen()) {
             try {
                 entityManagerFactory.close();
@@ -138,7 +128,6 @@ public abstract class DatabaseManager {
 
         try {
             entityManagerFactory = hibernateConfig.buildSessionFactory().unwrap(EntityManagerFactory.class);
-            entityManager = entityManagerFactory.createEntityManager();
             } catch (Exception e) {
             logger.error("Failed to initialize Hibernate: {}", e.getMessage());
             throw new RuntimeException("Hibernate initialization failed", e);
@@ -147,7 +136,7 @@ public abstract class DatabaseManager {
         logger.info("Hibernate ORM initialized successfully");
     }
 
-    public EntityManager getEntityManager() {
+    public EntityManagerFactory getEntityManagerFactory() {
-        return entityManager;
+        return entityManagerFactory;
     }
 }

src/main/java/com/mediamanager/service/delegate/DelegateActionManager.java

@@ -8,7 +8,7 @@ import com.mediamanager.service.delegate.handler.EchoHandler;
 import com.mediamanager.service.delegate.handler.HeartbeatHandler;
 import com.mediamanager.service.delegate.handler.genre.*;
 import com.mediamanager.service.genre.GenreService;
-import jakarta.persistence.EntityManager;
+import jakarta.persistence.EntityManagerFactory;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 
@@ -19,13 +19,13 @@ public class DelegateActionManager {
     private static final Logger logger = LogManager.getLogger(DelegateActionManager.class);
     
     private final Map<String, ActionHandler> handlerRegistry;
-    private final EntityManager entityManager;
+    private final EntityManagerFactory entityManagerFactory;
     private final GenreService genreService;
 
-    public DelegateActionManager(EntityManager entityManager) {
+    public DelegateActionManager(EntityManagerFactory entityManagerFactory) {
-        this.entityManager = entityManager;
+        this.entityManagerFactory = entityManagerFactory;
 
-        GenreRepository genreRepository = new GenreRepository(entityManager);
+        GenreRepository genreRepository = new GenreRepository(entityManagerFactory);
         this.genreService = new GenreService(genreRepository);
         logger.debug("DelegateActionManager created");
         this.handlerRegistry = new HashMap<>();