refactor code structure

src/main/java/wtf/beatrice/releasehive/db/HibernateManager.java

@@ -0,0 +1,43 @@
+package wtf.beatrice.releasehive.db;
+
+import org.hibernate.Session;
+import org.hibernate.SessionFactory;
+import org.hibernate.Transaction;
+import org.hibernate.cfg.Configuration;
+
+public class HibernateManager
+{
+    private static Session session;
+    private static SessionFactory sessionFactory;
+
+
+    private HibernateManager() {
+    }
+
+    public static void initialize() {
+        sessionFactory = new Configuration().configure("hibernate.cfg.xml").buildSessionFactory();
+    }
+
+    public static void shutdown() {
+        if(session != null && !session.isOpen()) {
+            session.close();
+        }
+        if(sessionFactory != null && sessionFactory.isOpen()) {
+            sessionFactory.close();
+        }
+    }
+
+
+    public static Session getSession() {
+         if(session != null && (!session.isOpen() || !session.isConnected())) {
+             session.close();
+         }
+
+        session = sessionFactory.openSession();
+        return session;
+    }
+
+    public static Transaction beginTransaction() {
+        return getSession().beginTransaction();
+    }
+}