keep subscriptions up to date when accessories are replaced

but the connection is _not_ torn down

also add the ability to modify accessories in a batch without
having to regenerate all AIDs and IIDs (and other temporary
data structures) at each intermediate step. You must use this
mechanism if you plan on replacing an existing accessory with an
equivalent one, but want to keep subscriptions intact.

Author: ccutrer

src/main/java/io/github/hapjava/characteristics/Characteristic.java

@@ -18,6 +18,8 @@
  * @author Andy Lintner
  */
 public interface Characteristic {
+  /** @return The UUID type for this characteristic. */
+  String getType();
 
   /**
    * Adds an attribute to the passed JsonObjectBuilder named "value" with the current value of the

src/main/java/io/github/hapjava/characteristics/impl/base/BaseCharacteristic.java

@@ -70,6 +70,12 @@ public BaseCharacteristic(
     this.unsubscriber = unsubscriber;
   }
 
+  @Override
+  /** {@inheritDoc} */
+  public String getType() {
+    return type;
+  }
+
   @Override
   /** {@inheritDoc} */
   public final CompletableFuture<JsonObject> toJson(int iid) {

src/main/java/io/github/hapjava/server/impl/HomekitRegistry.java

@@ -2,6 +2,7 @@
 
 import io.github.hapjava.accessories.HomekitAccessory;
 import io.github.hapjava.characteristics.Characteristic;
+import io.github.hapjava.server.impl.connections.SubscriptionManager;
 import io.github.hapjava.services.Service;
 import io.github.hapjava.services.impl.AccessoryInformationService;
 import java.util.ArrayList;
@@ -19,14 +20,16 @@ public class HomekitRegistry {
   private static final Logger logger = LoggerFactory.getLogger(HomekitRegistry.class);
 
   private final String label;
+  private final SubscriptionManager subscriptions;
   private final Map<Integer, HomekitAccessory> accessories;
   private final Map<HomekitAccessory, Map<Integer, Service>> services = new HashMap<>();
   private final Map<HomekitAccessory, Map<Integer, Characteristic>> characteristics =
       new HashMap<>();
   private boolean isAllowUnauthenticatedRequests = false;
 
-  public HomekitRegistry(String label) {
+  public HomekitRegistry(String label, SubscriptionManager subscriptions) {
     this.label = label;
+    this.subscriptions = subscriptions;
     this.accessories = new ConcurrentHashMap<>();
     reset();
   }
@@ -61,6 +64,7 @@ public synchronized void reset() {
       services.put(accessory, newServicesByInterfaceId);
       characteristics.put(accessory, newCharacteristicsByInterfaceId);
     }
+    subscriptions.resync(this);
   }
 
   public String getLabel() {
@@ -87,8 +91,8 @@ public void add(HomekitAccessory accessory) {
     accessories.put(accessory.getId(), accessory);
   }
 
-  public void remove(HomekitAccessory accessory) {
-    accessories.remove(accessory.getId());
+  public boolean remove(HomekitAccessory accessory) {
+    return accessories.remove(accessory.getId()) != null;
   }
 
   public boolean isAllowUnauthenticatedRequests() {

src/main/java/io/github/hapjava/server/impl/HomekitRoot.java

@@ -36,6 +36,8 @@ public class HomekitRoot {
   private final SubscriptionManager subscriptions = new SubscriptionManager();
   private boolean started = false;
   private int configurationIndex = 1;
+  private int nestedBatches = 0;
+  private boolean madeChanges = false;
 
   HomekitRoot(
       String label, HomekitWebHandler webHandler, InetAddress host, HomekitAuthInfo authInfo)
@@ -65,7 +67,7 @@ public class HomekitRoot {
     this.authInfo = authInfo;
     this.label = label;
     this.category = category;
-    this.registry = new HomekitRegistry(label);
+    this.registry = new HomekitRegistry(label, subscriptions);
   }
 
   HomekitRoot(
@@ -83,11 +85,19 @@ public class HomekitRoot {
     this(
         label, DEFAULT_ACCESSORY_CATEGORY, webHandler, authInfo, new JmdnsHomekitAdvertiser(jmdns));
   }
+
+  public synchronized void batchUpdate() {
+    if (this.nestedBatches == 0) madeChanges = false;
+    ++this.nestedBatches;
+  }
+
+  public synchronized void completeUpdateBatch() {
+    if (--this.nestedBatches == 0 && madeChanges) registry.reset();
+  }
+
   /**
-   * Add an accessory to be handled and advertised by this root. Any existing HomeKit connections
-   * will be terminated to allow the clients to reconnect and see the updated accessory list. When
-   * using this for a bridge, the ID of the accessory must be greater than 1, as that ID is reserved
-   * for the Bridge itself.
+   * Add an accessory to be handled and advertised by this root. When using this for a bridge, the
+   * ID of the accessory must be greater than 1, as that ID is reserved for the Bridge itself.
    *
    * @param accessory to advertise and handle.
    */
@@ -110,25 +120,28 @@ void addAccessorySkipRangeCheck(HomekitAccessory accessory) {
     if (logger.isTraceEnabled()) {
       accessory.getName().thenAccept(name -> logger.trace("Added accessory {}", name));
     }
-    if (started) {
+    madeChanges = true;
+    if (started && nestedBatches == 0) {
       registry.reset();
     }
   }
 
   /**
-   * Removes an accessory from being handled or advertised by this root. Any existing HomeKit
-   * connections will be terminated to allow the clients to reconnect and see the updated accessory
-   * list.
+   * Removes an accessory from being handled or advertised by this root.
    *
    * @param accessory accessory to cease advertising and handling
    */
   public void removeAccessory(HomekitAccessory accessory) {
-    this.registry.remove(accessory);
-    if (logger.isTraceEnabled()) {
-      accessory.getName().thenAccept(name -> logger.trace("Removed accessory {}", name));
-    }
-    if (started) {
-      registry.reset();
+    if (this.registry.remove(accessory)) {
+      if (logger.isTraceEnabled()) {
+        accessory.getName().thenAccept(name -> logger.trace("Removed accessory {}", name));
+      }
+      madeChanges = true;
+      if (started && nestedBatches == 0) {
+        registry.reset();
+      }
+    } else {
+      accessory.getName().thenAccept(name -> logger.warn("Could not remove accessory {}", name));
     }
   }
 
@@ -140,6 +153,7 @@ public void removeAccessory(HomekitAccessory accessory) {
    */
   public void start() {
     started = true;
+    madeChanges = false;
     registry.reset();
     webHandler
         .start(