Astro Background discovery for location changes

extensions/binding/org.eclipse.smarthome.binding.astro/README.md

@@ -10,17 +10,19 @@ This binding supports two Things: Sun and Moon
 
 ## Discovery
 
-Discovery is not necessary, because all calculations are done within the binding.
+You can use the auto discovery if you have a location set in "Configuration - System - Regional Settings - Location". This will automatically create a "Local Sun" and a "Local Moon" item for this location.
+
+If you change your system location the background discovery detects this change and applies it to the "Local Sun" and a "Local Moon" items automatically.
 
 ## Binding Configuration
 
 No binding configuration required.
 
 ## Thing Configuration
 
-A thing requires the geolocation (latitude, longitude) for which the calculation is done.
+A thing requires the geolocation (latitude, longitude, (altitude)) for which the calculation is done.
 Optionally, a refresh interval (in seconds) can be defined to also calculate positional data like azimuth and elevation.
-An complementary altitude (optional) configuration item can also be specified to sharpen results provided by Radiation group.
+The complementary altitude part of the geolocation parameter is optional and sharpens results provided by the Radiation group.
 
 ## Channels
 
@@ -123,26 +125,26 @@ sunrise is 22:10 but `latest` is set to 20:00 so the event/datetime value is mov
 Things:
 
 ```
-astro:sun:home  [ geolocation="xx.xxxxxx,xx.xxxxxx", altitude=100, interval=60 ]
-astro:moon:home [ geolocation="xx.xxxxxx,xx.xxxxxx", interval=60 ]
+astro:sun:home  [ geolocation="xx.xxxxxx,xx.xxxxxx,xx.xxx", interval=60 ]
+astro:moon:home [ geolocation="xx.xxxxxx,xx.xxxxxx,xx.xxx", interval=60 ]
 ```
 
 or optionally with an event offset
 
 ```
-astro:sun:home [ geolocation="xx.xxxxxx,xx.xxxxxx", altitude=100, interval=60 ] {
+astro:sun:home [ geolocation="xx.xxxxxx,xx.xxxxxx,xx.xxx", interval=60 ] {
     Channels:
         Type rangeEvent : rise#event [
             offset=-30
         ]
 }
-astro:moon:home [ geolocation="xx.xxxxxx,xx.xxxxxx", interval=60 ]
+astro:moon:home [ geolocation="xx.xxxxxx,xx.xxxxxx,xx.xxx", interval=60 ]
 ```
 
 or a datetime offset
 
 ```
-astro:sun:home [ geolocation="xx.xxxxxx,xx.xxxxxx", altitude=100, interval=60 ] {
+astro:sun:home [ geolocation="xx.xxxxxx,xx.xxxxxx,xx.xxx", interval=60 ] {
     Channels:
         Type start : rise#start [
             offset=5
@@ -156,7 +158,7 @@ astro:sun:home [ geolocation="xx.xxxxxx,xx.xxxxxx", altitude=100, interval=60 ]
 or a offset and latest
 
 ```
-astro:sun:home [ geolocation="xx.xxxxxx,xx.xxxxxx", altitude=100, interval=60 ] {
+astro:sun:home [ geolocation="xx.xxxxxx,xx.xxxxxx,xx.xxx", interval=60 ] {
     Channels:
         Type rangeEvent : rise#event [
             offset=-10,
@@ -187,3 +189,7 @@ then
     ...
 end
 ```
+
+##Tipps
+
+Do not worry if for example the "astro dawn" is "-" in the place that you set for your item. The reason might be that you live in a northern country and it is summer, because then by definition the sun is not 18 degrees below the horizon in the morning. For details see: https://en.wikipedia.org/wiki/Dawn Also while reading this wikipedia article you might come to the conclusion that you want to use "civil dawn" anyway.

extensions/binding/org.eclipse.smarthome.binding.astro/src/main/java/org/eclipse/smarthome/binding/astro/discovery/AstroDiscoveryLocationChangedTask.java

@@ -0,0 +1,23 @@
+package org.eclipse.smarthome.binding.astro.discovery;
+
+import org.eclipse.smarthome.core.library.types.PointType;
+
+public class AstroDiscoveryLocationChangedTask implements Runnable {
+
+    private AstroDiscoveryService astroDiscoveryService;
+    private PointType previousLocation;
+
+    public AstroDiscoveryLocationChangedTask(AstroDiscoveryService astroDiscoveryService) {
+        this.astroDiscoveryService = astroDiscoveryService;
+    }
+
+    @Override
+    public void run() {
+        PointType currentLocation = astroDiscoveryService.getLocationProvider().getLocation();
+        if (currentLocation != previousLocation) {
+            astroDiscoveryService.createResults(currentLocation);
+            previousLocation = currentLocation;
+        }
+    }
+
+}

extensions/binding/org.eclipse.smarthome.binding.astro/src/main/java/org/eclipse/smarthome/binding/astro/discovery/AstroDiscoveryService.java

@@ -9,14 +9,19 @@
 
 import static org.eclipse.smarthome.binding.astro.AstroBindingConstants.*;
 
+import java.text.ParseException;
 import java.util.Arrays;
 import java.util.HashSet;
 
-import org.eclipse.smarthome.binding.astro.AstroBindingConstants;
 import org.eclipse.smarthome.config.discovery.AbstractDiscoveryService;
 import org.eclipse.smarthome.config.discovery.DiscoveryResultBuilder;
 import org.eclipse.smarthome.core.i18n.LocationProvider;
 import org.eclipse.smarthome.core.library.types.PointType;
+import org.eclipse.smarthome.core.scheduler.CronExpression;
+import org.eclipse.smarthome.core.scheduler.CronHelper;
+import org.eclipse.smarthome.core.scheduler.Expression;
+import org.eclipse.smarthome.core.scheduler.ExpressionThreadPoolManager;
+import org.eclipse.smarthome.core.scheduler.ExpressionThreadPoolManager.ExpressionThreadPoolExecutor;
 import org.eclipse.smarthome.core.thing.ThingTypeUID;
 import org.eclipse.smarthome.core.thing.ThingUID;
 import org.slf4j.Logger;
@@ -31,42 +36,77 @@
 public class AstroDiscoveryService extends AbstractDiscoveryService {
     private final Logger logger = LoggerFactory.getLogger(AstroDiscoveryService.class);
     private static final int DISCOVER_TIMEOUT_SECONDS = 30;
+    private static final int LOCATION_CHANGED_CHECK_INTERVAL = 60;
     private LocationProvider locationProvider;
+    private final ExpressionThreadPoolExecutor scheduledExecutor;
+    private Runnable backgroundJob;
+
+    private static ThingUID SUN_THING = new ThingUID(THING_TYPE_SUN, LOCAL);
+    private static ThingUID MOON_THING = new ThingUID(THING_TYPE_MOON, LOCAL);
 
     /**
-     * Creates a AstroDiscoveryService with disabled autostart.
+     * Creates a AstroDiscoveryService with enabled autostart.
      */
     public AstroDiscoveryService() {
-        super(new HashSet<>(Arrays.asList(new ThingTypeUID(BINDING_ID, "-"))), DISCOVER_TIMEOUT_SECONDS, false);
+        super(new HashSet<>(Arrays.asList(new ThingTypeUID(BINDING_ID, "-"))), DISCOVER_TIMEOUT_SECONDS, true);
+
+        scheduledExecutor = ExpressionThreadPoolManager.getExpressionScheduledPool("astro");
     }
 
     @Override
     protected void startScan() {
         logger.debug("Starting Astro discovery scan");
-
         PointType location = locationProvider.getLocation();
-
         if (location == null) {
             logger.debug("LocationProvider.getLocation() is not set -> Will not provide any discovery results");
             return;
         }
+        createResults(location);
+    }
+
+    @Override
+    protected void startBackgroundDiscovery() {
+        Expression expression = null;
+        try {
+            expression = new CronExpression(
+                    CronHelper.createCronForRepeatEverySeconds(LOCATION_CHANGED_CHECK_INTERVAL));
+        } catch (ParseException e) {
+            return;
+        }
+        if (expression != null && backgroundJob == null) {
+            AstroDiscoveryLocationChangedTask job = new AstroDiscoveryLocationChangedTask(this);
+            scheduledExecutor.schedule(job, expression);
+            logger.info("Scheduled astro location-changed job every {} seconds", LOCATION_CHANGED_CHECK_INTERVAL);
+            backgroundJob = job;
+        }
+    }
 
-        ThingUID sunThing = new ThingUID(AstroBindingConstants.THING_TYPE_SUN, LOCAL);
-        ThingUID moonThing = new ThingUID(AstroBindingConstants.THING_TYPE_MOON, LOCAL);
+    @Override
+    protected void stopBackgroundDiscovery() {
+        if (backgroundJob != null) {
+            scheduledExecutor.remove(backgroundJob);
+            backgroundJob = null;
+        }
+    }
 
+    public void createResults(PointType location) {
         String propGeolocation;
         if (location.getAltitude() != null) {
             propGeolocation = String.format("%s,%s,%s", location.getLatitude(), location.getLongitude(),
                     location.getAltitude());
         } else {
             propGeolocation = String.format("%s,%s", location.getLatitude(), location.getLongitude());
         }
-        thingDiscovered(DiscoveryResultBuilder.create(sunThing).withLabel("Local Sun")
+        thingDiscovered(DiscoveryResultBuilder.create(SUN_THING).withLabel("Local Sun")
                 .withProperty("geolocation", propGeolocation).build());
-        thingDiscovered(DiscoveryResultBuilder.create(moonThing).withLabel("Local Moon")
+        thingDiscovered(DiscoveryResultBuilder.create(MOON_THING).withLabel("Local Moon")
                 .withProperty("geolocation", propGeolocation).build());
     }
 
+    public LocationProvider getLocationProvider() {
+        return locationProvider;
+    }
+
     protected void setLocationProvider(LocationProvider locationProvider) {
         this.locationProvider = locationProvider;
     }