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--- openjpa [2015/05/13 15:48]
+++ openjpa [2021/04/05 11:23] (current)
@@ Line 1: / Line 1: @@
+====== OpenJPA ======
+OpenJPA is a JPA implementation hosted by Apache.
+===== Default Fetch Type =====
+OpenJPA seems to have ''FetchType.LAZY'' as a default. Other JPA implementations have other defaults, f. e. EclipseLink. Keep in mind to explicitly set the fetch type (''FetchType.EAGER'')for relations if you want them loaded immediately.
+===== Remove Embedded Entity =====
+On a One-To-Many relationship the removal of the entities occurs by removing the entities from the list and merging the owner entity.
+This may lead to an owner entity having no embedded entity. When serializing this case it may lead to a null value for the list which is a valid value. But OpenJPA will ignore the embedded entities in this case and leaves them attached and in relation to the owner entity.
+The only way to remove all embedded entities seems to set an empty list to the relation attribute.
+<sxh java>
+public class ContactPerson {
+        @OneToMany(cascade=CascadeType.ALL, fetch=FetchType.EAGER, orphanRemoval=true)
+        private List<Phone> phones;
+        ...
+}
+</sxh>
+<sxh java>
+public class ContactPersonService {
+	public ContactPerson update(ContactPerson contactPerson) {
+		if (contactPerson.getPhones() == null) {
+			contactPerson.setPhones(new LinkedList());
+		}
+                return em.merge(contactPerson);
+        }
+}
+</sxh>
+===== Links =====
+  * [[http://openjpa.apache.org|Apache OpenJPA]]
+{{tag>java}}