bug fix. environment change is now also propagated when no remaining connection exists

Author: thsc42

src/main/java/net/sharksystem/asap/ASAPEnvironmentChangesListener.java

@@ -6,7 +6,7 @@ public interface ASAPEnvironmentChangesListener {
     /**
      * ASAP peers establish connections on their own and usually if possible. This
      * message is called if one or more connections could be established or got lost.
-     * @param peerList current list of peer we have a connection to
+     * @param peerList current list of peer we have a connection to (can be empty)
      */
     void onlinePeersChanged(Set<CharSequence> peerList);
 }

src/main/java/net/sharksystem/asap/engine/ASAPInternalPeerFS.java

@@ -439,7 +439,7 @@ private void notifyOnlinePeersChangedListener() {
             Log.writeLog(this, "no (more) peers: ");
         }
 
-        if(this.onlinePeersChangedListeners != null) {
+        if(this.onlinePeersChangedListeners != null && !this.onlinePeersChangedListeners.isEmpty()) {
             for(ASAPInternalOnlinePeersChangedListener listener: this.onlinePeersChangedListeners) {
                 listener.notifyOnlinePeersChanged(this);
             }
@@ -505,7 +505,7 @@ public synchronized void asapConnectionTerminated(Exception terminatingException
 
         StringBuilder sb = new StringBuilder();
         sb.append(this.getLogStart());
-        sb.append("asapConnection terminated connected to: ");
+        sb.append("asapConnection terminated; was connected to: ");
 
         if(peerName != null) {
             sb.append(peerName);

src/main/java/net/sharksystem/asap/listenermanager/ASAPEnvironmentChangesListenerManager.java

@@ -22,8 +22,10 @@ public void removeASAPEnvironmentChangesListener(ASAPEnvironmentChangesListener
     }
 
     public void notifyListeners(Set<CharSequence> peerList) {
-        if(peerList == null || peerList.isEmpty()) return;
+        if(peerList == null) peerList = new HashSet<>();
+
         if(this.listenerList == null || this.listenerList.isEmpty()) return;
+
         // make a copy of that list
         for(ASAPEnvironmentChangesListener listener : this.listenerList) {
             if(listener != null) listener.onlinePeersChanged(new HashSet<>(peerList));