added proper postgesql setup, implemented delete

Author: Juraj Veverka

hibernate-demo/README.md

@@ -26,8 +26,15 @@ Create user to access the database
 ./createdb username
 ./psql -U username
 \password
+
 # set password for username
 SELECT * FROM pg_catalog.pg_tables;
+
 # create database userdata
 create database userdata;
+GRANT ALL PRIVILEGES ON DATABASE userdata TO username;
+
+# select data from userdata database and table userdata
+\c userdata;
+select * from userdata;
 ```

hibernate-demo/src/main/java/itx/examples/hibernate/App.java

@@ -3,6 +3,7 @@
 import itx.examples.hibernate.entities.UserData;
 import itx.examples.hibernate.services.DataAccessService;
 import itx.examples.hibernate.services.DataAccessServiceImpl;
+import itx.examples.hibernate.utils.HibernateUtil;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
@@ -12,16 +13,26 @@ public class App {
 
     final private static Logger LOG = LoggerFactory.getLogger(App.class);
 
-    public static void main(String[] args) {
-        DataAccessService dataAccessService = new DataAccessServiceImpl();
+    public static void main(String[] args) throws Exception {
+        DataAccessService dataAccessService = new DataAccessServiceImpl(HibernateUtil.getPostgresql10Properties());
+
+        //1. create and save new user
         UserData userData = new UserData("Juraj", "Veverka", "[email protected]");
         dataAccessService.saveUserData(userData);
         LOG.info("UserData saved");
+
+        //2. get all users
         Collection<UserData> userDataCollection = dataAccessService.getUserData();
         LOG.info("UserData [{}]", userDataCollection.size());
+
+        //3. delete all users
         userDataCollection.forEach(u->{
             LOG.info("UserData: {}", u);
+            dataAccessService.deleteUserData(u.getId());
         });
+
+        //4. close the service
+        dataAccessService.close();
     }
 
 }

hibernate-demo/src/main/java/itx/examples/hibernate/entities/UserData.java

@@ -20,6 +20,10 @@ public class UserData {
     @Column(name = "email")
     private String email;
 
+    public UserData(long id) {
+        this.id = id;
+    }
+
     public UserData() {
     }
 
@@ -67,4 +71,15 @@ public String getEmail() {
     public void setEmail(String email) {
         this.email = email;
     }
+
+    @Override
+    public String toString() {
+        return "UserData{" +
+                "id=" + id +
+                ", firstName='" + firstName + '\'' +
+                ", lastName='" + lastName + '\'' +
+                ", email='" + email + '\'' +
+                '}';
+    }
+
 }

hibernate-demo/src/main/java/itx/examples/hibernate/services/DataAccessService.java

@@ -4,10 +4,12 @@
 
 import java.util.Collection;
 
-public interface DataAccessService {
+public interface DataAccessService extends AutoCloseable {
 
     void saveUserData(UserData userData);
 
     Collection<UserData> getUserData();
 
+    void deleteUserData(long id);
+
 }

hibernate-demo/src/main/java/itx/examples/hibernate/services/DataAccessServiceImpl.java

@@ -5,36 +5,70 @@
 import org.hibernate.Session;
 import org.hibernate.SessionFactory;
 import org.hibernate.Transaction;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 
 import java.util.Collection;
+import java.util.Properties;
 
 public class DataAccessServiceImpl implements DataAccessService {
 
+    final private static Logger LOG = LoggerFactory.getLogger(DataAccessServiceImpl.class);
+
     private final SessionFactory sessionFactory;
 
-    public DataAccessServiceImpl() {
-        this.sessionFactory = HibernateUtil.getSessionFactory();
+    public DataAccessServiceImpl(Properties properties) {
+        this.sessionFactory = HibernateUtil.getSessionFactory(properties);
     }
 
     @Override
     public void saveUserData(UserData userData) {
         Transaction transaction = null;
-        try(Session session = this.sessionFactory.openSession()) {
+        try (Session session = this.sessionFactory.openSession()) {
             transaction = session.beginTransaction();
+            LOG.info("save user data, TX started");
             session.save(userData);
             transaction.commit();
+            LOG.info("save user data, TX committed");
         } catch (Exception e) {
+            LOG.error("Error: ", e);
             if (transaction != null) {
+                LOG.info("user data rollback, TX rollback");
                 transaction.rollback();
             }
         }
     }
 
     @Override
     public Collection<UserData> getUserData() {
-        try (Session session = HibernateUtil.getSessionFactory().openSession()) {
+        try (Session session = this.sessionFactory.openSession()) {
             return session.createQuery("from UserData", UserData.class).list();
         }
     }
 
+    @Override
+    public void deleteUserData(long id) {
+        Transaction transaction = null;
+        try (Session session = this.sessionFactory.openSession()) {
+            transaction = session.beginTransaction();
+            LOG.info("delete user data id={}, TX started", id);
+            //Delete a transient  object
+            UserData userData = new UserData(id);
+            session.delete(userData);
+            transaction.commit();
+            LOG.info("delete user data id={}, TX committed", id);
+        } catch (Exception e) {
+            LOG.error("Error: ", e);
+            if (transaction != null) {
+                LOG.info("user data rollback, TX rollback");
+                transaction.rollback();
+            }
+        }
+    }
+
+    @Override
+    public void close() throws Exception {
+        this.sessionFactory.close();
+    }
+
 }

hibernate-demo/src/main/java/itx/examples/hibernate/utils/HibernateUtil.java

@@ -14,10 +14,8 @@ public final class HibernateUtil {
     private HibernateUtil() {
     }
 
-    public static SessionFactory getSessionFactory() {
-        Configuration configuration = new Configuration();
+    public static Properties getPostgresql10Properties() {
         Properties properties = new Properties();
-
         properties.put(Environment.DRIVER, "org.postgresql.Driver");
         // jdbc:postgresql://host:port/database
         properties.put(Environment.URL, "jdbc:postgresql://127.0.0.1:5432/userdata");
@@ -26,7 +24,12 @@ public static SessionFactory getSessionFactory() {
         properties.put(Environment.DIALECT, "org.hibernate.dialect.PostgreSQL10Dialect");
         properties.put(Environment.SHOW_SQL, "true");
         properties.put(Environment.CURRENT_SESSION_CONTEXT_CLASS, "thread");
-        properties.put(Environment.HBM2DDL_AUTO, "create-drop");
+        properties.put(Environment.HBM2DDL_AUTO, "update");
+        return properties;
+    }
+
+    public static SessionFactory getSessionFactory(Properties properties) {
+        Configuration configuration = new Configuration();
 
         configuration.setProperties(properties);
         configuration.addAnnotatedClass(UserData.class);