Prevent duplicate event listeners (#20554)

Signed-off-by: Michael Lobstein <michael.lobstein@gmail.com>

Author: mlobstein

bundles/org.openhab.binding.monopriceaudio/src/main/java/org/openhab/binding/monopriceaudio/internal/handler/MonopriceAudioHandler.java

@@ -462,9 +462,9 @@ private synchronized boolean openConnection() {
     private synchronized void closeConnection() {
         if (connector.isConnected()) {
             connector.close();
-            connector.removeEventListener(this);
             logger.debug("closeConnection(): disconnected");
         }
+        connector.removeEventListener(this);
     }
 
     @Override
@@ -698,10 +698,10 @@ private void processMonoprice70Update(MonopriceAudioZoneDTO zoneData, MonopriceA
      * @param channelType the channel type to be updated
      */
     private void updateChannelState(String zoneId, String channelType) {
-        MonopriceAudioZoneDTO zoneData = zoneDataMap.get(zoneId);
+        final MonopriceAudioZoneDTO zoneData = zoneDataMap.get(zoneId);
 
         if (zoneData != null) {
-            String channel = amp.getZoneName(zoneId) + CHANNEL_DELIMIT + channelType;
+            final String channel = amp.getZoneName(zoneId) + CHANNEL_DELIMIT + channelType;
 
             if (!isLinked(channel)) {
                 return;

bundles/org.openhab.binding.nuvo/src/main/java/org/openhab/binding/nuvo/internal/handler/NuvoHandler.java

@@ -680,10 +680,10 @@ private synchronized boolean openConnection() {
     private synchronized void closeConnection() {
         if (connector.isConnected()) {
             connector.close();
-            connector.removeEventListener(this);
             pollStatusNeeded = true;
             logger.debug("closeConnection(): disconnected");
         }
+        connector.removeEventListener(this);
     }
 
     /**

bundles/org.openhab.binding.oppo/src/main/java/org/openhab/binding/oppo/internal/handler/OppoHandler.java

@@ -379,9 +379,9 @@ private synchronized void closeConnection() {
 
         if (connector.isConnected()) {
             connector.close();
-            connector.removeEventListener(this);
             logger.debug("closeConnection(): disconnected");
         }
+        connector.removeEventListener(this);
     }
 
     /**