--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/main/java/edu/harvard/iq/dataverse/DatasetLinkingServiceBean.java	Tue Sep 08 17:00:21 2015 +0200
@@ -0,0 +1,86 @@
+/*
+ * To change this license header, choose License Headers in Project Properties.
+ * To change this template file, choose Tools | Templates
+ * and open the template in the editor.
+ */
+package edu.harvard.iq.dataverse;
+
+import java.util.ArrayList;
+import java.util.List;
+import javax.ejb.Stateless;
+import javax.inject.Named;
+import javax.persistence.EntityManager;
+import javax.persistence.PersistenceContext;
+import javax.persistence.Query;
+import javax.persistence.TypedQuery;
+
+/**
+ *
+ * @author skraffmiller
+ */
+@Stateless
+@Named
+public class DatasetLinkingServiceBean implements java.io.Serializable {
+
+    @PersistenceContext(unitName = "VDCNet-ejbPU")
+    private EntityManager em;
+
+    /**
+     * @todo Should this method simply be deleted? It isn't used anywhere and is
+     * throwing exceptions: Syntax error parsing [select object(o.dataverse.id)
+     * from DatasetLinkingDataverse as o where o.linkingDataverse.id
+     * =:linkingDataverseId order by o.id]
+     */
+    @Deprecated
+    public List<Dataset> findLinkedDataverses(Long linkingDataverseId) {
+        List<Dataset> retList = new ArrayList();
+        Query query = em.createQuery("select object(o.dataverse.id) from DatasetLinkingDataverse as o where o.linkingDataverse.id =:linkingDataverseId order by o.id");
+        query.setParameter("linkingDataverseId", linkingDataverseId);
+        for (Object o : query.getResultList()) {
+            DatasetLinkingDataverse convterted = (DatasetLinkingDataverse) o;
+            retList.add(convterted.getDataset());
+        }
+        return retList;
+    }
+
+    public List<Dataset> findDatasetsThisDataverseIdHasLinkedTo(Long dataverseId) {
+        List<Dataset> datasets = new ArrayList<>();
+        TypedQuery<DatasetLinkingDataverse> typedQuery = em.createQuery("SELECT OBJECT(o) FROM DatasetLinkingDataverse AS o WHERE o.linkingDataverse.id = :dataverseId", DatasetLinkingDataverse.class);
+        typedQuery.setParameter("dataverseId", dataverseId);
+        List<DatasetLinkingDataverse> datasetLinkingDataverses = typedQuery.getResultList();
+        for (DatasetLinkingDataverse datasetLinkingDataverse : datasetLinkingDataverses) {
+            datasets.add(datasetLinkingDataverse.getDataset());
+        }
+        return datasets;
+    }
+
+    public List<Dataverse> findLinkingDataverses(Long datasetId) {
+        List<Dataverse> retList = new ArrayList();
+        for (DatasetLinkingDataverse dld : findDatasetLinkingDataverses(datasetId)) {
+            retList.add(dld.getLinkingDataverse());
+        }
+        return retList;
+    }
+
+    public List<DatasetLinkingDataverse> findDatasetLinkingDataverses(Long datasetId) {
+        return em.createQuery("select object(o) from DatasetLinkingDataverse as o where o.dataset.id =:datasetId order by o.id")
+                .setParameter("datasetId", datasetId)
+                .getResultList();
+    }
+
+    public void save(DatasetLinkingDataverse datasetLinkingDataverse) {
+        if (datasetLinkingDataverse.getId() == null) {
+            em.persist(datasetLinkingDataverse);
+        } else {
+            em.merge(datasetLinkingDataverse);
+        }
+    }
+
+    public boolean alreadyLinked(Dataverse dataverse, Dataset dataset) {
+        TypedQuery<DatasetLinkingDataverse> typedQuery = em.createQuery("SELECT OBJECT(o) FROM DatasetLinkingDataverse AS o WHERE o.linkingDataverse.id = :dataverseId AND o.dataset.id = :datasetId", DatasetLinkingDataverse.class);
+        typedQuery.setParameter("dataverseId", dataverse.getId());
+        typedQuery.setParameter("datasetId", dataset.getId());
+        return !typedQuery.getResultList().isEmpty();
+    }
+
+}