Set date format to ISO 8601 and added ivo://ivoa.net/vospace/core#date property

src/main/java/it/inaf/oats/vospace/persistence/NodeDAO.java

@@ -190,8 +190,10 @@ public class NodeDAO {
         addProperty(NodeProperties.LENGTH_URI, rs.getString("content_length"),
                 properties);
 
-        addProperty(NodeProperties.INITIAL_CREATION_TIME_URI, rs.getString("created_on"),
-                properties);
+        String creationTime = rs.getString("created_on").replace(" ", "T");
+        
+        addProperty(NodeProperties.INITIAL_CREATION_TIME_URI, creationTime, properties);
+        addProperty(NodeProperties.DATE_URI, creationTime, properties); // required by CADC
 
         addProperty(NodeProperties.CREATOR_URI, rs.getString("creator_id"),
                 properties);

src/test/java/it/inaf/oats/vospace/persistence/NodeDAOTest.java

@@ -62,6 +62,10 @@ public class NodeDAOTest {
         assertEquals("true", NodeProperties.getNodePropertyAsListByURI(root, NodeProperties.PUBLIC_READ_URI).get(0));
 
         assertEquals("group1 group2", NodeProperties.getNodePropertyByURI(root.getNodes().get(0), NodeProperties.GROUP_READ_URI));
+
+        String bTime = NodeProperties.getNodePropertyByURI(root.getNodes().get(0), NodeProperties.INITIAL_CREATION_TIME_URI);
+        assertTrue(bTime.contains("T"));
+        assertEquals(bTime, NodeProperties.getNodePropertyByURI(root.getNodes().get(0), NodeProperties.DATE_URI));
     }
 
     @Test