[icalendar] Ensure Bridge is initialized and calendar is available to update child Things (#9337)

* Ensure Bridge is initialized and calendar is available to update child Things

Signed-off-by: Christoph Weitkamp <github@christophweitkamp.de>

bundles/org.openhab.binding.icalendar/src/main/java/org/openhab/binding/icalendar/internal/handler/EventFilterHandler.java

@@ -45,6 +45,7 @@ import org.openhab.core.thing.binding.BaseThingHandler;
 import org.openhab.core.thing.binding.ThingHandlerCallback;
 import org.openhab.core.thing.binding.builder.ChannelBuilder;
 import org.openhab.core.thing.binding.builder.ThingBuilder;
+import org.openhab.core.thing.util.ThingHandlerHelper;
 import org.openhab.core.types.Command;
 import org.openhab.core.types.RefreshType;
 import org.openhab.core.types.UnDefType;
@@ -64,12 +65,10 @@ public class EventFilterHandler extends BaseThingHandler implements CalendarUpda
     private final List<ResultChannelSet> resultChannels;
     private final TimeZoneProvider tzProvider;
     private @Nullable ScheduledFuture<?> updateFuture;
-    private boolean initFinished;
 
     public EventFilterHandler(Thing thing, TimeZoneProvider tzProvider) {
         super(thing);
         resultChannels = new CopyOnWriteArrayList<>();
-        initFinished = false;
         this.tzProvider = tzProvider;
     }
 
@@ -101,8 +100,6 @@ public class EventFilterHandler extends BaseThingHandler implements CalendarUpda
 
     @Override
     public void initialize() {
-        updateStatus(ThingStatus.UNKNOWN);
-
         Bridge iCalendarBridge = getBridge();
         if (iCalendarBridge == null) {
             updateStatus(ThingStatus.OFFLINE, ThingStatusDetail.CONFIGURATION_ERROR,
@@ -120,12 +117,12 @@ public class EventFilterHandler extends BaseThingHandler implements CalendarUpda
         configuration = config;
 
         updateChannelSet(config);
-        initFinished = true;
         if (iCalendarBridge.getStatus() != ThingStatus.ONLINE) {
             updateStatus(ThingStatus.OFFLINE, ThingStatusDetail.BRIDGE_OFFLINE);
             return;
         }
-        updateStates();
+
+        updateStatus(ThingStatus.UNKNOWN);
     }
 
     @Override
@@ -254,7 +251,7 @@ public class EventFilterHandler extends BaseThingHandler implements CalendarUpda
      * Updates all states and channels. Reschedules an update if no error occurs.
      */
     private void updateStates() {
-        if (!initFinished) {
+        if (!ThingHandlerHelper.isHandlerInitialized(this)) {
             logger.debug("Ignoring call for updating states as this instance is not initialized yet.");
             return;
         }

bundles/org.openhab.binding.icalendar/src/main/java/org/openhab/binding/icalendar/internal/handler/ICalendarHandler.java

@@ -158,6 +158,7 @@ public class ICalendarHandler extends BaseBridgeHandler implements CalendarUpdat
                     // reload calendar file asynchronously
                     if (reloadCalendar()) {
                         updateStates();
+                        updateChildren();
                     } else {
                         updateStatus(ThingStatus.OFFLINE, ThingStatusDetail.COMMUNICATION_ERROR,
                                 "The calendar seems to be configured correctly, but the local copy of calendar could not be loaded.");
@@ -176,21 +177,19 @@ public class ICalendarHandler extends BaseBridgeHandler implements CalendarUpdat
         }
     }
 
+    @Override
+    public void childHandlerInitialized(ThingHandler childHandler, Thing childThing) {
+        final AbstractPresentableCalendar calendar = runtimeCalendar;
+        if (calendar != null) {
+            updateChild(childHandler);
+        }
+    }
+
     @Override
     public void onCalendarUpdated() {
         if (reloadCalendar()) {
             updateStates();
-            for (Thing childThing : getThing().getThings()) {
+            updateChildren();
-                ThingHandler handler = childThing.getHandler();
-                if (handler instanceof CalendarUpdateListener) {
-                    try {
-                        logger.trace("Notifying {} about fresh calendar.", handler.getThing().getUID());
-                        ((CalendarUpdateListener) handler).onCalendarUpdated();
-                    } catch (Exception e) {
-                        logger.trace("The update of a child handler failed. Ignoring.", e);
-                    }
-                }
-            }
         } else {
             logger.trace("Calendar was updated, but loading failed.");
         }
@@ -389,4 +388,27 @@ public class ICalendarHandler extends BaseBridgeHandler implements CalendarUpdat
             updateStatesLastCalledTime = now;
         }
     }
+
+    /**
+     * Updates all children of this handler.
+     */
+    private void updateChildren() {
+        getThing().getThings().forEach(childThing -> updateChild(childThing.getHandler()));
+    }
+
+    /**
+     * Updates a specific child handler.
+     *
+     * @param childHandler the handler to be updated
+     */
+    private void updateChild(@Nullable ThingHandler childHandler) {
+        if (childHandler instanceof CalendarUpdateListener) {
+            logger.trace("Notifying {} about fresh calendar.", childHandler.getThing().getUID());
+            try {
+                ((CalendarUpdateListener) childHandler).onCalendarUpdated();
+            } catch (Exception e) {
+                logger.trace("The update of a child handler failed. Ignoring.", e);
+            }
+        }
+    }
 }