Wire monitored property to OPC UA monitored items

The monitored bool now calls enableMonitoring/disableMonitoring on
the Value attribute. Adds publishingInterval property (default 100ms).
Value is no longer read at init — delivered by the monitored item.
Empty 4th demo page to verify monitoring stops when navigating away.

1 files changed, 13 insertions, 0 deletions

diff --git a/src/OpcUaMonitoredNode.h b/src/OpcUaMonitoredNode.h
index 5895bea..3e86cb4 100644
--- a/src/OpcUaMonitoredNode.h
+++ b/src/OpcUaMonitoredNode.h
@@ -56,6 +56,8 @@ class OpcUaMonitoredNode : public QObject, public QQmlParserStatus
   Q_PROPERTY (QString nodeId READ nodeId WRITE setNodeId NOTIFY nodeIdChanged)
   Q_PROPERTY (
       bool monitored READ monitored WRITE setMonitored NOTIFY monitoredChanged)
+  Q_PROPERTY (double publishingInterval READ publishingInterval WRITE
+                  setPublishingInterval NOTIFY publishingIntervalChanged)
   Q_PROPERTY (QVariant value READ value NOTIFY valueChanged)
   Q_PROPERTY (bool writable READ writable NOTIFY writableChanged)
   Q_PROPERTY (OpcUaNodeInfo info READ info NOTIFY infoChanged)
@@ -69,6 +71,9 @@ public:
   bool monitored () const;
   void setMonitored (bool monitored);
 
+  double publishingInterval () const;
+  void setPublishingInterval (double interval);
+
   QVariant value () const;
   bool writable () const;
   OpcUaNodeInfo info () const;
@@ -89,6 +94,7 @@ public:
 signals:
   void nodeIdChanged ();
   void monitoredChanged ();
+  void publishingIntervalChanged ();
   void valueChanged ();
   void writableChanged ();
   void infoChanged ();
@@ -101,14 +107,21 @@ private slots:
   void handleClientConnectedChanged ();
   void handleAttributeWritten (QOpcUa::NodeAttribute attr,
                                QOpcUa::UaStatusCode statusCode);
+  void handleEnableMonitoringFinished (QOpcUa::NodeAttribute attr,
+                                       QOpcUa::UaStatusCode statusCode);
+  void handleDisableMonitoringFinished (QOpcUa::NodeAttribute attr,
+                                        QOpcUa::UaStatusCode statusCode);
 
 private:
   void setupNode ();
   void teardownNode ();
+  void startMonitoring ();
+  void stopMonitoring ();
   QVariant coerceValue (const QVariant &input) const;
 
   QString m_nodeId;
   bool m_monitored = true;
+  double m_publishingInterval = 100.0;
   bool m_componentComplete = false;
 
   QOpcUaNode *m_node = nullptr;