Added NullDbValue exception-class from previous bad commit

catalogue/NullDbValue.cpp

+/*
+ * The CERN Tape Archive (CTA) project
+ * Copyright (C) 2015  CERN
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "catalogue/NullDbValue.hpp"
+
+namespace cta {
+namespace catalogue {
+
+//------------------------------------------------------------------------------
+// constructor
+//------------------------------------------------------------------------------
+NullDbValue::NullDbValue(const std::string &context, const bool embedBacktrace):
+  Exception(context, embedBacktrace) {
+}
+
+} // namespace catalogue
+} // namespace cta

catalogue/NullDbValue.hpp

+/*
+ * The CERN Tape Archive (CTA) project
+ * Copyright (C) 2015  CERN
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#pragma once
+
+#include "common/exception/Exception.hpp"
+
+namespace cta {
+namespace catalogue {
+
+/**
+ * An exception class representing an unexpected encounter with a NULL database
+ * value (not to be confused with a NULL C/C++ pointer).
+ */
+class NullDbValue: public exception::Exception {
+public:
+
+  /**
+   * Constructor.
+   *
+   * @param context optional context string added to the message
+   * at initialisation time.
+   * @param embedBacktrace whether to embed a backtrace of where the
+   * exception was throw in the message
+   */
+  NullDbValue(const std::string &context = "", const bool embedBacktrace = true);
+
+}; // class NullDbValue
+
+} // namespace catalogue
+} // namespace cta