v0.2.54..v0.2.55 changeset RelationData.h

diff --git a/hoot-core/src/main/cpp/hoot/core/elements/RelationData.h b/hoot-core/src/main/cpp/hoot/core/elements/RelationData.h
index fe2040d..e05bc26 100644
--- a/hoot-core/src/main/cpp/hoot/core/elements/RelationData.h
+++ b/hoot-core/src/main/cpp/hoot/core/elements/RelationData.h
@@ -60,6 +60,8 @@ public:
       return getElementId() == other.getElementId() && getRole() == other.getRole();
     }
 
+    bool isNull() const { return _eid.isNull(); }
+
     QString toString() const
     {
       return QString("Entry: role: %1, eid: %2").arg(role).arg(_eid.toString());