[knx] Adapt to core, temperature differences (openhab#15573)

Special handling for temperature differences in °F and °F/%,
DPT 9.002 and 9.003, needs to be adapted due to change in core.

Refs openhab/openhab-core#3792.

Implementation is valid for 4.0 and 4.x snapshot.

Fixes openhab#15567.

Signed-off-by: Holger Friedrich <mail@holger-friedrich.de>

bundles/org.openhab.binding.knx/src/main/java/org/openhab/binding/knx/internal/dpt/ValueEncoder.java

@@ -33,6 +33,7 @@
 import org.openhab.core.library.types.StringType;
 import org.openhab.core.library.types.UpDownType;
 import org.openhab.core.library.unit.SIUnits;
+import org.openhab.core.library.unit.Units;
 import org.openhab.core.types.Type;
 import org.openhab.core.util.ColorUtil;
 import org.slf4j.Logger;
@@ -192,10 +193,15 @@ private static String handleNumericTypes(String dptId, String mainNumber, DPT dp
                         unit = unit.replace("K", "°C");
                     }
                 } else if (value.toString().contains("°F")) {
-                    if (unit != null) {
-                        unit = unit.replace("K", "°F");
+                    // an new approach to handle temperature differences was introduced to core
+                    // after 4.0, stripping the unit and and creating a new QuantityType works
+                    // both with core release 4.0 and current snapshot
+                    boolean perPercent = value.toString().contains("/%");
+                    value = new QuantityType<>(((QuantityType<?>) value).doubleValue() * 5.0 / 9.0, Units.KELVIN);
+                    // PercentType needs to be adapted
+                    if (perPercent) {
+                        value = ((QuantityType<?>) value).multiply(BigDecimal.valueOf(100));
                     }
-                    value = ((QuantityType<?>) value).multiply(BigDecimal.valueOf(5.0 / 9.0));
                 }
             } else if (DPTXlator4ByteFloat.DPT_LIGHT_QUANTITY.getID().equals(dptId)) {
                 if (!value.toString().contains("J")) {

bundles/org.openhab.binding.knx/src/test/java/org/openhab/binding/knx/internal/dpt/DPTTest.java

@@ -109,8 +109,7 @@ void testToDPT9ValueFromQuantityType() {
         assertEquals("1", ValueEncoder.encode(new QuantityType<>("1 K"), "9.002"));
         assertEquals("1", ValueEncoder.encode(new QuantityType<>("1000 mK"), "9.002"));
         assertEquals("1", ValueEncoder.encode(new QuantityType<>("1 °C"), "9.002"));
-        // TODO
-        // assertTrue(ValueEncoder.encode(new QuantityType<>("1 °F"), "9.002").startsWith("0.55"));
+        assertTrue(ValueEncoder.encode(new QuantityType<>("1 °F"), "9.002").startsWith("0.55"));
         assertEquals("1", ValueEncoder.encode(new QuantityType<>("1 K/h"), "9.003"));
         assertEquals("1", ValueEncoder.encode(new QuantityType<>("1 °C/h"), "9.003"));
         assertEquals("1", ValueEncoder.encode(new QuantityType<>("1000 mK/h"), "9.003"));
@@ -134,8 +133,7 @@ void testToDPT9ValueFromQuantityType() {
         assertEquals("12", ValueEncoder.encode(new QuantityType<>("12 W/m²"), "9.022"));
         assertEquals("1", ValueEncoder.encode(new QuantityType<>("1 K/%"), "9.023"));
         assertEquals("1", ValueEncoder.encode(new QuantityType<>("1 °C/%"), "9.023"));
-        // TODO
-        // assertTrue(ValueEncoder.encode(new QuantityType<>("1 °F/%"), "9.023").startsWith("0.55"));
+        assertTrue(ValueEncoder.encode(new QuantityType<>("1 °F/%"), "9.023").startsWith("0.55"));
         assertEquals("1", ValueEncoder.encode(new QuantityType<>("1 kW"), "9.024"));
         assertEquals("1", ValueEncoder.encode(new QuantityType<>("1 l/h"), "9.025"));
         assertEquals("60", ValueEncoder.encode(new QuantityType<>("1 l/min"), "9.025"));