Added StructuredDataNode support

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

@@ -16,6 +16,7 @@ import javax.sql.DataSource;
 import net.ivoa.xml.vospace.v2.ContainerNode;
 import net.ivoa.xml.vospace.v2.DataNode;
 import net.ivoa.xml.vospace.v2.Property;
+import net.ivoa.xml.vospace.v2.StructuredDataNode;
 import net.ivoa.xml.vospace.v2.View;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.beans.factory.annotation.Value;
@@ -211,6 +212,9 @@ public class NodeDAO {
             case "data":
                 node = new DataNode();
                 break;
+            case "structured":
+                node = new StructuredDataNode();
+                break;
             default:
                 throw new UnsupportedOperationException("Node type " + type + " not supported yet");
         }