v0.2.54..v0.2.55 changeset MemoryUsageChecker.h

diff --git a/hoot-core/src/main/cpp/hoot/core/util/MemoryUsageChecker.h b/hoot-core/src/main/cpp/hoot/core/util/MemoryUsageChecker.h
new file mode 100644
index 0000000..75f612b
--- /dev/null
+++ b/hoot-core/src/main/cpp/hoot/core/util/MemoryUsageChecker.h
@@ -0,0 +1,77 @@
+/*
+ * This file is part of Hootenanny.
+ *
+ * Hootenanny 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/>.
+ *
+ * --------------------------------------------------------------------
+ *
+ * The following copyright notices are generated automatically. If you
+ * have a new notice to add, please use the format:
+ * " * @copyright Copyright ..."
+ * This will properly maintain the copyright information. DigitalGlobe
+ * copyrights will be updated automatically.
+ *
+ * @copyright Copyright (C) 2020 DigitalGlobe (http://www.digitalglobe.com/)
+ */
+
+#ifndef MEMORY_USAGE_CHECKER_H
+#define MEMORY_USAGE_CHECKER_H
+
+namespace hoot
+{
+
+/**
+ * Utility for checking available memory (Singleton)
+ *
+ * This has been put to use so far in the most likely locations to use large amounts of memory but
+ * could be potentially added anywhere in the code. Use memory.usage.checker.interval if calling
+ * in a loop.
+ *
+ * @todo This should probably be integrated with max.memory.usage setting to where the warning is
+ * logged based on what percentage the process memory is of that value instead of the total
+ * available.
+ */
+class MemoryUsageChecker
+{
+
+public:
+
+  static MemoryUsageChecker& getInstance();
+
+  /**
+   * Checks the available physical and virtual memory and logs a single message when it drops below
+   * a configurable threshold
+   */
+  void check();
+
+private:
+
+  MemoryUsageChecker();
+  /** Default constructor/destructor */
+  ~MemoryUsageChecker() = default;
+  /** Delete copy constructor and assignment operator */
+  MemoryUsageChecker(const MemoryUsageChecker&) = delete;
+  MemoryUsageChecker& operator=(const MemoryUsageChecker&) = delete;
+
+  bool _enabled;
+  // memory usage percentage threshold above which a notification is logged
+  double _notificationThreshold;
+
+  bool _loggedPhysicalMemNotification;
+  bool _loggedVirtualMemNotification;
+};
+
+}
+
+#endif // MEMORY_USAGE_CHECKER_H