v0.2.55..v0.2.56 changeset AbstractDistanceExtractor.h

diff --git a/hoot-core/src/main/cpp/hoot/core/algorithms/extractors/AbstractDistanceExtractor.h b/hoot-core/src/main/cpp/hoot/core/algorithms/extractors/AbstractDistanceExtractor.h
index b4ca914..d8f0159 100644
--- a/hoot-core/src/main/cpp/hoot/core/algorithms/extractors/AbstractDistanceExtractor.h
+++ b/hoot-core/src/main/cpp/hoot/core/algorithms/extractors/AbstractDistanceExtractor.h
@@ -23,7 +23,7 @@
  * copyrights will be updated automatically.
  *
  * @copyright Copyright (C) 2005 VividSolutions (http://www.vividsolutions.com/)
- * @copyright Copyright (C) 2015, 2017, 2018, 2019 DigitalGlobe (http://www.digitalglobe.com/)
+ * @copyright Copyright (C) 2015, 2017, 2018, 2019, 2020 DigitalGlobe (http://www.digitalglobe.com/)
  */
 #ifndef ABSTRACTDISTANCEEXTRACTOR_H
 #define ABSTRACTDISTANCEEXTRACTOR_H
@@ -55,6 +55,9 @@ public:
 
   static std::string className() { return "hoot::AbstractDistanceExtractor"; }
 
+  AbstractDistanceExtractor() = default;
+  virtual ~AbstractDistanceExtractor() = default;
+
   virtual double combinedEnvelopeDiagonalDistance(const OsmMap& map,
     const std::shared_ptr<const Element>& target,
     const std::shared_ptr<const Element>& candidate) const;