Overload DatasetField method to remove type check

src/main/java/edu/harvard/iq/dataverse/DatasetField.java

@@ -54,15 +54,18 @@ public int compare(DatasetField o1, DatasetField o2) {
                                     o2.getDatasetFieldType().getDisplayOrder() );
     }};
 
-    public static DatasetField createNewEmptyDatasetField(DatasetFieldType dsfType, Object dsv) {
+    public static DatasetField createNewEmptyDatasetField(DatasetFieldType dsfType, DatasetVersion dsv) {
 
         DatasetField dsfv = createNewEmptyDatasetField(dsfType);
-        //TODO - a better way to handle this?
-        if (dsv.getClass().getName().equals("edu.harvard.iq.dataverse.DatasetVersion")){
-                   dsfv.setDatasetVersion((DatasetVersion)dsv); 
-        } else {
-            dsfv.setTemplate((Template)dsv);
-        }
+        dsfv.setDatasetVersion(dsv);
+
+        return dsfv;
+    }
+
+    public static DatasetField createNewEmptyDatasetField(DatasetFieldType dsfType, Template dsv) {
+
+        DatasetField dsfv = createNewEmptyDatasetField(dsfType);
+        dsfv.setTemplate(dsv);
 
         return dsfv;
     }
@@ -545,25 +548,28 @@ public String toString() {
         return "edu.harvard.iq.dataverse.DatasetField[ id=" + id + " ]";
     }
 
-    public DatasetField copy(Object version) {
+    public DatasetField copy(DatasetVersion version) {
         return copy(version, null);
     }
+    public DatasetField copy(Template template) {
+        return copy(template, null);
+    }
 
     // originally this was an overloaded method, but we renamed it to get around an issue with Bean Validation
     // (that looked t overloaded methods, when it meant to look at overriden methods
     public DatasetField copyChild(DatasetFieldCompoundValue parent) {
         return copy(null, parent);
     }
 
-    private DatasetField copy(Object version, DatasetFieldCompoundValue parent) {
+    private DatasetField copy(Object versionOrTemplate, DatasetFieldCompoundValue parent) {
         DatasetField dsf = new DatasetField();
         dsf.setDatasetFieldType(datasetFieldType);
 
-        if (version != null) {
-            if (version.getClass().getName().equals("edu.harvard.iq.dataverse.DatasetVersion")) {
-                dsf.setDatasetVersion((DatasetVersion) version);               
+        if (versionOrTemplate != null) {
+            if (versionOrTemplate instanceof DatasetVersion) {
+                dsf.setDatasetVersion((DatasetVersion) versionOrTemplate);               
             } else {
-                dsf.setTemplate((Template) version);
+                dsf.setTemplate((Template) versionOrTemplate);
             }
         }
 

src/test/java/edu/harvard/iq/dataverse/DatasetFieldTest.java

@@ -0,0 +1,64 @@
+package edu.harvard.iq.dataverse;
+
+import edu.harvard.iq.dataverse.DatasetFieldType.FieldType;
+import edu.harvard.iq.dataverse.mocks.MocksFactory;
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNotEquals;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+import static org.junit.jupiter.api.Assertions.assertNull;
+
+
+class DatasetFieldTest {
+    @Test
+    void testCreateNewEmptyDatasetField_withEmptyTemplate() {
+        Template template = new Template();
+
+        DatasetField field = DatasetField.createNewEmptyDatasetField(new DatasetFieldType("subject", FieldType.TEXT, false), template);
+        assertTrue(field.getTemplate() == template);
+        assertTrue(template.getDatasetFields().isEmpty());
+    }
+
+    @Test
+    void testNotEqualDatasetFields() {
+        DatasetFieldType type1 = new DatasetFieldType("subject", FieldType.TEXT, false);
+        Template template1 = new Template();
+        DatasetField field1 = DatasetField.createNewEmptyDatasetField(type1, template1);
+        field1.setId(MocksFactory.nextId());
+        DatasetFieldType type2 = new DatasetFieldType("subject", FieldType.TEXT, false);
+        Template template2 = new Template();
+        DatasetField field2 = DatasetField.createNewEmptyDatasetField(type2, template2);
+        field2.setId(MocksFactory.nextId());
+
+        assertNotEquals(field1, field2);
+        assertNotEquals(field1, template2);
+    }
+
+    @Test
+    void testEqualDatasetFields() {
+        DatasetField field1 = DatasetField.createNewEmptyDatasetField(new DatasetFieldType("subject", FieldType.TEXT, false), new Template());
+        field1.setId(100L);
+        DatasetField field2 = DatasetField.createNewEmptyDatasetField(new DatasetFieldType("subject", FieldType.TEXT, false), new Template());
+
+        // Fields are not equal before both have IDs set
+        assertNotEquals(field1, field2);
+
+        field2.setId(100L);
+
+        assertEquals(field1, field2);
+    }
+
+    @Test
+    void testCopyDatasetFields() {
+        DatasetField field1 = DatasetField.createNewEmptyDatasetField(new DatasetFieldType("subject", FieldType.TEXT, false), new Template());
+        field1.setId(100L);
+        DatasetField field2 = field1.copy(field1.getTemplate());
+
+        assertNull(field2.getId());
+        // A copy of a field should not be equal
+        assertNotEquals(field1, field2);
+
+        assertEquals(field2.getDatasetFieldType(), field1.getDatasetFieldType());
+    }
+}