Fix for new Homekit restriction on write-only characteristics not

exposing a value.

Author: Andy Lintner

src/main/java/com/beowulfe/hap/characteristics/BaseCharacteristic.java

@@ -151,7 +151,13 @@ public void supplyValue(JsonObjectBuilder builder) {
 	 */
 	protected abstract T getDefault();
 
-	private void setJsonValue(JsonObjectBuilder builder, T value) {
+	/**
+	 * Writes the value key to the serialized characteristic
+	 * 
+	 * @param builder The JSON builder to add the value to
+	 * @param value The value to add
+	 */
+	protected void setJsonValue(JsonObjectBuilder builder, T value) {
 		//I don't like this - there should really be a way to construct a disconnected JSONValue...
 		if (value instanceof Boolean) {
 			builder.add("value", (Boolean) value);

src/main/java/com/beowulfe/hap/characteristics/WriteOnlyBooleanCharacteristic.java

@@ -2,6 +2,8 @@
 
 import java.util.concurrent.CompletableFuture;
 
+import javax.json.JsonObjectBuilder;
+
 /**
  * A characteristic that provides a boolean that can only be written to, not read.
  *
@@ -27,4 +29,8 @@ public WriteOnlyBooleanCharacteristic(String type, String description) {
 	@Override
 	protected final CompletableFuture<Boolean> getValue() { return CompletableFuture.completedFuture(false); }
 
+	@Override
+	protected final void setJsonValue(JsonObjectBuilder builder, Boolean value) {
+		//Do nothing - non-readable characteristics cannot have a value key set
+	}
 }