Use singleton for EntityManagerFactory

1 files changed, 54 insertions, 0 deletions

diff --git a/src/jpa/EntityManagerFactorySingleton.java b/src/jpa/EntityManagerFactorySingleton.java
new file mode 100644
index 0000000..dbd4873
--- /dev/null
+++ b/src/jpa/EntityManagerFactorySingleton.java
@@ -0,0 +1,54 @@
+/**
+ * 
+ */
+package jpa;
+
+import javax.annotation.PreDestroy;
+import javax.enterprise.context.ApplicationScoped;
+import javax.persistence.EntityManagerFactory;
+import javax.persistence.Persistence;
+
+/**
+ * A singleton for application wide {@link EntityManagerFactory}. Increases
+ * performance significant.
+ *
+ * @author Stefan Suhren
+ * @version 1.0
+ */
+@ApplicationScoped
+public class EntityManagerFactorySingleton
+{
+   private static final String DB_PU = "catalog";
+
+   private static final EntityManagerFactorySingleton singleton = new EntityManagerFactorySingleton();
+
+   private EntityManagerFactory emf;
+
+   private EntityManagerFactorySingleton()
+   {
+   }
+
+   public static EntityManagerFactorySingleton getInstance()
+   {
+      return singleton;
+   }
+
+   public EntityManagerFactory getEntityManagerFactory()
+   {
+      if (emf == null)
+      {
+         emf = Persistence.createEntityManagerFactory(DB_PU);
+      }
+      return emf;
+   }
+
+   @PreDestroy
+   public void closeEmf()
+   {
+      if (emf != null && emf.isOpen())
+      {
+         emf.close();
+      }
+      emf = null;
+   }
+}