Fix DS-3263. Check for null MetadataField whenever using metadataFieldService.findByElement()

dspace-api/src/main/java/org/dspace/content/CollectionServiceImpl.java

@@ -123,14 +123,23 @@ public class CollectionServiceImpl extends DSpaceObjectServiceImpl<Collection> i
 
     @Override
     public List<Collection> findAll(Context context) throws SQLException {
-        MetadataField nameField = metadataFieldService.findByElement(context, "dc", "title", null);
+        MetadataField nameField = metadataFieldService.findByElement(context, MetadataSchema.DC_SCHEMA, "title", null);
-        return collectionDAO.findAll(context, nameField);
+        if(nameField==null)
+        {
+            throw new IllegalArgumentException("Required metadata field '" + MetadataSchema.DC_SCHEMA + ".title' doesn't exist!");
+        }
 
+        return collectionDAO.findAll(context, nameField);
     }
 
     @Override
     public List<Collection> findAll(Context context, Integer limit, Integer offset) throws SQLException {
-        MetadataField nameField = metadataFieldService.findByElement(context, "dc", "title", null);
+        MetadataField nameField = metadataFieldService.findByElement(context, MetadataSchema.DC_SCHEMA, "title", null);
+        if(nameField==null)
+        {
+            throw new IllegalArgumentException("Required metadata field '" + MetadataSchema.DC_SCHEMA + ".title' doesn't exist!");
+        }
+
         return collectionDAO.findAll(context, nameField, limit, offset);
     }
 

dspace-api/src/main/java/org/dspace/content/CommunityServiceImpl.java

@@ -137,12 +137,22 @@ public class CommunityServiceImpl extends DSpaceObjectServiceImpl<Community> imp
     @Override
     public List<Community> findAll(Context context) throws SQLException {
         MetadataField sortField = metadataFieldService.findByElement(context, MetadataSchema.DC_SCHEMA, "title", null);
+        if(sortField==null)
+        {
+            throw new IllegalArgumentException("Required metadata field '" + MetadataSchema.DC_SCHEMA + ".title' doesn't exist!");
+        }
+
         return communityDAO.findAll(context, sortField);
     }
 
     @Override
     public List<Community> findAll(Context context, Integer limit, Integer offset) throws SQLException {
         MetadataField nameField = metadataFieldService.findByElement(context, MetadataSchema.DC_SCHEMA, "title", null);
+        if(nameField==null)
+        {
+            throw new IllegalArgumentException("Required metadata field '" + MetadataSchema.DC_SCHEMA + ".title' doesn't exist!");
+        }
+
         return communityDAO.findAll(context, nameField, limit, offset);
     }
 
@@ -151,6 +161,11 @@ public class CommunityServiceImpl extends DSpaceObjectServiceImpl<Community> imp
     {
         // get all communities that are not children
         MetadataField sortField = metadataFieldService.findByElement(context, MetadataSchema.DC_SCHEMA, "title", null);
+        if(sortField==null)
+        {
+            throw new IllegalArgumentException("Required metadata field '" + MetadataSchema.DC_SCHEMA + ".title' doesn't exist!");
+        }
+
         return communityDAO.findAllNoParent(context, sortField);
     }
 

dspace-api/src/main/java/org/dspace/content/DSpaceObjectServiceImpl.java

@@ -207,7 +207,7 @@ public abstract class DSpaceObjectServiceImpl<T extends DSpaceObject> implements
     public void addMetadata(Context context, T dso, String schema, String element, String qualifier, String lang, List<String> values) throws SQLException {
         MetadataField metadataField = metadataFieldService.findByElement(context, schema, element, qualifier);
         if (metadataField == null) {
-            throw new SQLException("bad_dublin_core schema=" + schema + "." + element + "." + qualifier);
+            throw new SQLException("bad_dublin_core schema=" + schema + "." + element + "." + qualifier + ". Metadata field does not exist!");
         }
 
         addMetadata(context, dso, metadataField, lang, values);
@@ -219,7 +219,7 @@ public abstract class DSpaceObjectServiceImpl<T extends DSpaceObject> implements
         // until update() is called.
         MetadataField metadataField = metadataFieldService.findByElement(context, schema, element, qualifier);
         if (metadataField == null) {
-            throw new SQLException("bad_dublin_core schema=" + schema + "." + element + "." + qualifier);
+            throw new SQLException("bad_dublin_core schema=" + schema + "." + element + "." + qualifier + ". Metadata field does not exist!");
         }
         addMetadata(context, dso, metadataField, lang, values, authorities, confidences);
     }

dspace-api/src/main/java/org/dspace/content/ItemServiceImpl.java

@@ -192,6 +192,11 @@ public class ItemServiceImpl extends DSpaceObjectServiceImpl<Item> implements It
     public Iterator<Item> findBySubmitterDateSorted(Context context, EPerson eperson, Integer limit) throws SQLException {
 
         MetadataField metadataField = metadataFieldService.findByElement(context, MetadataSchema.DC_SCHEMA, "date", "accessioned");
+        if(metadataField==null)
+        {
+            throw new IllegalArgumentException("Required metadata field '" + MetadataSchema.DC_SCHEMA + ".date.accessioned' doesn't exist!");
+        }
+
         return itemDAO.findBySubmitter(context, eperson, metadataField, limit);
     }