[homekit] Use BigDecimal to ensure accurate rounding (openhab#7777)

Temperature values are often not reported correctly in HomeKit especially when they are in Fahrenheit this also has the side effect of having no decimal when using Fahrenheit temperatures. This intends to fix this and allows for accurate rounding and reporting of temperatures. Signed-off-by: Ethan Dye <[email protected]> Signed-off-by: Daan Meijer <[email protected]>
DaanMeijer · Sep 1, 2020 · c1bfc02 · c1bfc02
1 parent 10697f2
commit c1bfc02
Show file tree

Hide file tree

Showing 3 changed files with 20 additions and 32 deletions.
diff --git a/...c/main/java/org/openhab/io/homekit/internal/accessories/AbstractHomekitAccessoryImpl.java b/...c/main/java/org/openhab/io/homekit/internal/accessories/AbstractHomekitAccessoryImpl.java
@@ -18,12 +18,19 @@
 import java.util.Map;
 import java.util.Optional;
 import java.util.concurrent.CompletableFuture;
+import java.math.BigDecimal;
+import java.math.RoundingMode;
+
+import javax.measure.Quantity;
+import javax.measure.Unit;
 
 import org.eclipse.jdt.annotation.NonNull;
 import org.eclipse.jdt.annotation.Nullable;
 import org.eclipse.smarthome.core.items.GenericItem;
 import org.eclipse.smarthome.core.items.Item;
 import org.eclipse.smarthome.core.types.State;
+import org.eclipse.smarthome.core.library.unit.SIUnits;
+import org.eclipse.smarthome.core.library.unit.ImperialUnits;
 import org.openhab.io.homekit.internal.HomekitAccessoryUpdater;
 import org.openhab.io.homekit.internal.HomekitCharacteristicType;
 import org.openhab.io.homekit.internal.HomekitSettings;
@@ -177,4 +184,17 @@ protected <T> T getAccessoryConfiguration(String key, @NonNull T defaultValue) {
     protected void addCharacteristic(HomekitTaggedItem characteristic) {
         characteristics.add(characteristic);
     }
+
+    private <T extends Quantity<T>> double convertAndRound(double value, Unit<T> from, Unit<T> to) {
+      double rawValue = from == to ? value : from.getConverterTo(to).convert(value);
+      return new BigDecimal(rawValue).setScale(1, RoundingMode.HALF_UP).doubleValue();
+    }
+
+    protected double convertToCelsius(double degrees){
+      return convertAndRound(degrees, getSettings().useFahrenheitTemperature ? ImperialUnits.FAHRENHEIT : SIUnits.CELSIUS, SIUnits.CELSIUS);
+    }
+
+    protected double convertFromCelsius(double degrees){
+      return convertAndRound(degrees, getSettings().useFahrenheitTemperature ? SIUnits.CELSIUS : ImperialUnits.FAHRENHEIT, ImperialUnits.FAHRENHEIT);
+    }
 }
diff --git a/...c/main/java/org/openhab/io/homekit/internal/accessories/HomekitTemperatureSensorImpl.java b/...c/main/java/org/openhab/io/homekit/internal/accessories/HomekitTemperatureSensorImpl.java
@@ -55,20 +55,4 @@ public void subscribeCurrentTemperature(HomekitCharacteristicChangeCallback call
     public void unsubscribeCurrentTemperature() {
         unsubscribe(HomekitCharacteristicType.CURRENT_TEMPERATURE);
     }
-
-    protected double convertToCelsius(double degrees) {
-        if (getSettings().useFahrenheitTemperature) {
-            return Math.round((5d / 9d) * (degrees - 32d) * 1000d) / 1000d;
-        } else {
-            return degrees;
-        }
-    }
-
-    protected double convertFromCelsius(double degrees) {
-        if (getSettings().useFahrenheitTemperature) {
-            return Math.round((((9d / 5d) * degrees) + 32d) * 10d) / 10d;
-        } else {
-            return degrees;
-        }
-    }
 }
diff --git a/...ekit/src/main/java/org/openhab/io/homekit/internal/accessories/HomekitThermostatImpl.java b/...ekit/src/main/java/org/openhab/io/homekit/internal/accessories/HomekitThermostatImpl.java
@@ -236,20 +236,4 @@ public void unsubscribeTargetState() {
     public void unsubscribeTargetTemperature() {
         unsubscribe(HomekitCharacteristicType.TARGET_TEMPERATURE);
     }
-
-    protected double convertToCelsius(double degrees) {
-        if (getSettings().useFahrenheitTemperature) {
-            return Math.round((5d / 9d) * (degrees - 32d) * 1000d) / 1000d;
-        } else {
-            return degrees;
-        }
-    }
-
-    protected double convertFromCelsius(double degrees) {
-        if (getSettings().useFahrenheitTemperature) {
-            return Math.round((((9d / 5d) * degrees) + 32d) * 10d) / 10d;
-        } else {
-            return degrees;
-        }
-    }
 }