Added PersistenceManager and Namedqueries

In theory, this code is all we need for database integration

src/main/java/envoy/server/data/Message.java

@@ -4,6 +4,9 @@ import java.util.Date;
 
 import javax.persistence.Entity;
 import javax.persistence.Id;
+import javax.persistence.NamedQueries;
+import javax.persistence.NamedQuery;
+import javax.persistence.Table;
 import javax.persistence.Temporal;
 import javax.persistence.TemporalType;
 
@@ -23,6 +26,13 @@ import envoy.data.MessageBuilder;
  * @since Envoy Server Standalone v0.1-alpha
  */
 @Entity
+@Table(name = "messages")
+@NamedQueries(
+	{ @NamedQuery(query = "SELECT m FROM Message m WHERE m.recipient =:recipient AND m.state = 1", name = "getUnreadMessages"), @NamedQuery(
+		query = "SELECT m FROM Message m WHERE m.sender =:sender AND m.state = :state",
+		name = "find read messages"//TODO do we need this namedQuery?
+	), @NamedQuery(query = "SELECT m FROM Message m WHERE m.id = :messageId", name = "get message") }//TODO do we need this namedQuery?
+)
 public class Message {
 
 	@Id

src/main/java/envoy/server/data/User.java

@@ -7,6 +7,8 @@ import javax.persistence.Entity;
 import javax.persistence.GeneratedValue;
 import javax.persistence.GenerationType;
 import javax.persistence.Id;
+import javax.persistence.NamedQuery;
+import javax.persistence.Table;
 import javax.persistence.Temporal;
 import javax.persistence.TemporalType;
 
@@ -24,6 +26,8 @@ import javax.persistence.TemporalType;
  * @since Envoy Server Standalone v0.1-alpha
  */
 @Entity
+@Table(name = "users")
+@NamedQuery(query = "SELECT u FROM DBUser u WHERE u.id = :id", name = "getUserById")
 public class User {
 
 	@Id

src/main/java/envoy/server/database/PersistenceManager.java

@@ -1,21 +1,96 @@
 package envoy.server.database;
 
+import java.util.List;
+
+import javax.persistence.EntityManager;
+import javax.persistence.Persistence;
+
+import org.hibernate.Session;
+
+import envoy.server.data.Message;
+import envoy.server.data.User;
 
 /**
  * Project: <strong>envoy-server-standalone</strong><br>
  * File: <strong>PersistenceManager.java</strong><br>
- * Created: <strong>3 Jan 2020</strong><br>
+ * Created: <strong>1 Jan 2020</strong><br>
  *
  * @author Leon Hofmeister
  * @since Envoy Server Standalone v0.1-alpha
  */
 public class PersistenceManager {
 
+	private EntityManager entityManager = Persistence.createEntityManagerFactory("envoy").createEntityManager();
+
 	/**
 	 *
 	 * @since Envoy Server Standalone v0.1-alpha
 	 */
-	public PersistenceManager() { // TODO Auto-generated constructor stub
+	public PersistenceManager() {
+		/*
+		 * // TODO TESTING
+		 * User user = new User(3, "t");
+		 * User user2 = new User(2, "w");
+		 * Message msg = new MessageBuilder(user.getId(), user2.getId()).build();
+		 * entityManager.getTransaction().begin();
+		 * entityManager.persist(user);
+		 * entityManager.persist(user2);
+		 * entityManager.persist(msg);
+		 * entityManager.getTransaction().commit();
+		 */ // TODO delete until here
 	}
 
+	/**
+	 * Adds a user to the database.
+	 *
+	 * @param User the {@link User} to add to the database
+	 * @since Envoy Server Standalone v0.1-alpha
+	 */
+	public void addUser(User User) { entityManager.persist(User); }
+
+	/**
+	 * Adds a message to the database.
+	 *
+	 * @param message the {@link Message} to add to the database
+	 * @since Envoy Server Standalone v0.1-alpha
+	 */
+	public void addMessage(Message message) { entityManager.persist(message); }// TODO these functions or the one below?
+
+	/**
+	 * This is a delegate function for {@link EntityManager#persist} in order to add
+	 * an {@link User} / a {@link Message} into the database
+	 *
+	 * @param obj the object to add to the database
+	 * @since Envoy Server Standalone v0.1-alpha
+	 */
+	public void addObject(Object obj) { entityManager.persist(obj); }
+
+	/**
+	 * Updates a row of database objects, either a Message or a User with new data.
+	 *
+	 * @param obj the object to update (existing User/Message)
+	 * @since Envoy Server Standalone v0.1-alpha
+	 */
+	public void updateObject(Object obj) { entityManager.unwrap(Session.class).merge(obj); }
+
+	/**
+	 * Searches for a user with a specific id.
+	 *
+	 * @param id - the id to search for
+	 * @return the user with the specified id
+	 * @since Envoy Server Standalone v0.1-alpha
+	 */
+	public User getUserById(long id) { return (User) entityManager.createNamedQuery("getUserById").setParameter("id", id).getSingleResult(); }
+
+	/**
+	 * Returns all messages received while being offline.
+	 *
+	 * @param user - the user who wants to receive his unread messages
+	 * @return all messages that the client does not yet have (unread messages)
+	 * @since Envoy Server Standalone v0.1-alpha
+	 */
+	@SuppressWarnings("unchecked")
+	public List<Message> getUnreadMessages(User user) {// TODO may need to be changed to clientId
+		return entityManager.createNamedQuery("getUnreadMessages").setParameter("recipient", user).getResultList();
+	}
 }