Added tests for service-layer pattern

service-layer/src/main/java/com/iluwatar/servicelayer/common/BaseEntity.java

@@ -12,8 +12,37 @@ import javax.persistence.Version;
  */
 @MappedSuperclass
 @Inheritance(strategy = InheritanceType.TABLE_PER_CLASS)
-public class BaseEntity {
+public abstract class BaseEntity {
 
   @Version
   private Long version;
+
+  /**
+   * Indicates the unique id of this entity
+   *
+   * @return The id of the entity, or 'null' when not persisted
+   */
+  public abstract Long getId();
+
+  /**
+   * Set the id of this entity
+   *
+   * @param id The new id
+   */
+  public abstract void setId(Long id);
+
+  /**
+   * Get the name of this entity
+   *
+   * @return The name of the entity
+   */
+  public abstract String getName();
+
+  /**
+   * Set the name of this entity
+   *
+   * @param name The new name
+   */
+  public abstract void setName(final String name);
+
 }

service-layer/src/main/java/com/iluwatar/servicelayer/hibernate/HibernateUtil.java

@@ -1,41 +1,56 @@
 package com.iluwatar.servicelayer.hibernate;
 
-import org.hibernate.SessionFactory;
-import org.hibernate.cfg.Configuration;
-
 import com.iluwatar.servicelayer.spell.Spell;
 import com.iluwatar.servicelayer.spellbook.Spellbook;
 import com.iluwatar.servicelayer.wizard.Wizard;
 
+import org.hibernate.SessionFactory;
+import org.hibernate.cfg.Configuration;
+
 /**
- * 
  * Produces the Hibernate {@link SessionFactory}.
- *
  */
 public class HibernateUtil {
 
-  private static final SessionFactory SESSION_FACTORY;
-
-  static {
-    try {
-      SESSION_FACTORY =
-          new Configuration().addAnnotatedClass(Wizard.class).addAnnotatedClass(Spellbook.class)
-              .addAnnotatedClass(Spell.class)
-              .setProperty("hibernate.dialect", "org.hibernate.dialect.H2Dialect")
-              .setProperty("hibernate.connection.url", "jdbc:h2:mem:test;DB_CLOSE_DELAY=-1")
-              .setProperty("hibernate.current_session_context_class", "thread")
-              .setProperty("hibernate.show_sql", "true")
-              .setProperty("hibernate.hbm2ddl.auto", "create-drop").buildSessionFactory();
-    } catch (Throwable ex) {
-      System.err.println("Initial SessionFactory creation failed." + ex);
-      throw new ExceptionInInitializerError(ex);
-    }
-  }
+  /**
+   * The cached session factory
+   */
+  private static volatile SessionFactory sessionFactory;
 
   private HibernateUtil() {
   }
 
-  public static SessionFactory getSessionFactory() {
-    return SESSION_FACTORY;
+  /**
+   * Create the current session factory instance, create a new one when there is none yet.
+   *
+   * @return The session factory
+   */
+  public static synchronized SessionFactory getSessionFactory() {
+    if (sessionFactory == null) {
+      try {
+        sessionFactory =
+            new Configuration().addAnnotatedClass(Wizard.class).addAnnotatedClass(Spellbook.class)
+                .addAnnotatedClass(Spell.class)
+                .setProperty("hibernate.dialect", "org.hibernate.dialect.H2Dialect")
+                .setProperty("hibernate.connection.url", "jdbc:h2:mem:test;DB_CLOSE_DELAY=-1")
+                .setProperty("hibernate.current_session_context_class", "thread")
+                .setProperty("hibernate.show_sql", "true")
+                .setProperty("hibernate.hbm2ddl.auto", "create-drop").buildSessionFactory();
+      } catch (Throwable ex) {
+        System.err.println("Initial SessionFactory creation failed." + ex);
+        throw new ExceptionInInitializerError(ex);
+      }
+    }
+    return sessionFactory;
   }
+
+  /**
+   * Drop the current connection, resulting in a create-drop clean database next time. This is
+   * mainly used for JUnit testing since one test should not influence the other
+   */
+  public static void dropSession() {
+    getSessionFactory().close();
+    sessionFactory = null;
+  }
+
 }

service-layer/src/main/java/com/iluwatar/servicelayer/spell/SpellDaoImpl.java

@@ -1,12 +1,12 @@
 package com.iluwatar.servicelayer.spell;
 
+import com.iluwatar.servicelayer.common.DaoBaseImpl;
+
 import org.hibernate.Criteria;
 import org.hibernate.Session;
 import org.hibernate.Transaction;
 import org.hibernate.criterion.Restrictions;
 
-import com.iluwatar.servicelayer.common.DaoBaseImpl;
-
 /**
  * 
  * SpellDao implementation.
@@ -24,7 +24,6 @@ public class SpellDaoImpl extends DaoBaseImpl<Spell> implements SpellDao {
       Criteria criteria = session.createCriteria(persistentClass);
       criteria.add(Restrictions.eq("name", name));
       result = (Spell) criteria.uniqueResult();
-      result.getSpellbook().getWizards().size();
       tx.commit();
     } catch (Exception e) {
       if (tx != null) {

service-layer/src/main/java/com/iluwatar/servicelayer/spellbook/Spellbook.java

@@ -6,6 +6,7 @@ import java.util.Set;
 import javax.persistence.CascadeType;
 import javax.persistence.Column;
 import javax.persistence.Entity;
+import javax.persistence.FetchType;
 import javax.persistence.GeneratedValue;
 import javax.persistence.Id;
 import javax.persistence.ManyToMany;
@@ -50,7 +51,7 @@ public class Spellbook extends BaseEntity {
 
   private String name;
 
-  @ManyToMany(mappedBy = "spellbooks")
+  @ManyToMany(mappedBy = "spellbooks", fetch = FetchType.EAGER)
   private Set<Wizard> wizards;
 
   @OneToMany(mappedBy = "spellbook", orphanRemoval = true, cascade = CascadeType.ALL)