Fixed NPE when accessory was removed from registry

Author: gdombiak

src/main/java/com/beowulfe/hap/impl/HomekitRegistry.java

@@ -1,20 +1,14 @@
 package com.beowulfe.hap.impl;
 
-import java.util.ArrayList;
-import java.util.Collection;
-import java.util.Collections;
-import java.util.HashMap;
-import java.util.List;
-import java.util.Map;
-import java.util.concurrent.ConcurrentHashMap;
-
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
-
 import com.beowulfe.hap.HomekitAccessory;
 import com.beowulfe.hap.Service;
 import com.beowulfe.hap.characteristics.Characteristic;
 import com.beowulfe.hap.impl.services.AccessoryInformationService;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.util.*;
+import java.util.concurrent.ConcurrentHashMap;
 
 public class HomekitRegistry {
 
@@ -72,7 +66,11 @@ public List<Service> getServices(Integer aid) {
 	}
 
 	public Map<Integer, Characteristic> getCharacteristics(Integer aid) {
-		return Collections.unmodifiableMap(characteristics.get(accessories.get(aid)));
+		Map<Integer, Characteristic> characteristics = this.characteristics.get(accessories.get(aid));
+		if (characteristics == null) {
+			return Collections.emptyMap();
+		}
+		return Collections.unmodifiableMap(characteristics);
 	}
 
 	public void add(HomekitAccessory accessory) {

src/main/java/com/beowulfe/hap/impl/json/CharacteristicsController.java

@@ -1,18 +1,5 @@
 package com.beowulfe.hap.impl.json;
 
-import java.io.ByteArrayInputStream;
-import java.io.ByteArrayOutputStream;
-
-import javax.json.Json;
-import javax.json.JsonArray;
-import javax.json.JsonArrayBuilder;
-import javax.json.JsonObject;
-import javax.json.JsonObjectBuilder;
-import javax.json.JsonValue;
-
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
-
 import com.beowulfe.hap.characteristics.Characteristic;
 import com.beowulfe.hap.characteristics.EventableCharacteristic;
 import com.beowulfe.hap.impl.HomekitRegistry;
@@ -21,6 +8,13 @@
 import com.beowulfe.hap.impl.http.HttpRequest;
 import com.beowulfe.hap.impl.http.HttpResponse;
 import com.beowulfe.hap.impl.responses.NotFoundResponse;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import javax.json.*;
+import java.io.ByteArrayInputStream;
+import java.io.ByteArrayOutputStream;
+import java.util.Map;
 
 public class CharacteristicsController {
 
@@ -49,9 +43,19 @@ public HttpResponse get(HttpRequest request) throws Exception {
 			int aid = Integer.parseInt(parts[0]);
 			int iid = Integer.parseInt(parts[1]);
 			JsonObjectBuilder characteristic = Json.createObjectBuilder();
-			registry.getCharacteristics(aid).get(iid).supplyValue(characteristic);
+			Map<Integer, Characteristic> characteristicMap = registry.getCharacteristics(aid);
+			if (!characteristicMap.isEmpty()) {
+				Characteristic targetCharacteristic = characteristicMap.get(iid);
+				if (targetCharacteristic != null) {
+					targetCharacteristic.supplyValue(characteristic);
 
-			characteristics.add(characteristic.add("aid", aid).add("iid", iid).build());
+					characteristics.add(characteristic.add("aid", aid).add("iid", iid).build());
+				} else {
+					logger.warn("Accessory " + aid + " does not have characteristic " + iid + "Request: " + uri);
+				}
+			} else {
+				logger.warn("Accessory " + aid + " has no characteristics or does not exist. Request: " + uri);
+			}
 		}
 		try(ByteArrayOutputStream baos = new ByteArrayOutputStream()) {
 			Json.createWriter(baos).write(Json.createObjectBuilder().add("characteristics", characteristics.build()).build());