Gate digital output event creation on listner / binding presence

pi4j-core/src/main/java/com/pi4j/event/EventManager.java

@@ -43,6 +43,11 @@ public EventManager(SOURCE_TYPE source, EventDelegate<LISTENER_TYPE,EVENT_TYPE>
         this.delegate = delegate;
     }
 
+    /** Returns true if this event manager has at least one listener. Used to skip event creation otherwise. */
+    public boolean hasListeners() {
+        return !listeners.isEmpty();
+    }
+
     public SOURCE_TYPE add(LISTENER_TYPE ... listener){
         listeners.addAll(List.of(listener));
         return this.source;

pi4j-core/src/main/java/com/pi4j/io/binding/BindingManager.java

@@ -71,4 +71,8 @@ public SOURCE_TYPE unbind(BINDING_TYPE... binding) {
         bindings.removeAll(List.of(binding));
         return this.source;
     }
+
+    public boolean hasBindings() {
+        return !bindings.isEmpty();
+    }
 }

pi4j-core/src/main/java/com/pi4j/io/gpio/digital/DigitalBase.java

@@ -107,6 +107,11 @@ public DIGITAL_TYPE unbind(DigitalBinding ... binding) {
         //return (DIGITAL_TYPE)this;
     }
 
+    public boolean hasListenersOrBindings() {
+        return stateChangeEventManager.hasListeners() || bindings.hasBindings();
+    }
+
+
     /**
      * Dispatch DigitalChangeEvent on digital input state changes
      *

pi4j-core/src/main/java/com/pi4j/io/gpio/digital/DigitalOutputBase.java

@@ -77,7 +77,9 @@ public DigitalOutput state(DigitalState state) throws IOException {
 
         if(!this.state.equals(state)){
             this.state = state;
-            this.dispatch(new DigitalStateChangeEvent<>(this, this.state));
+            if (this.hasListenersOrBindings()) {
+                this.dispatch(new DigitalStateChangeEvent<>(this, this.state));
+            }
         }
         return this;
     }

pi4j-core/src/main/java/com/pi4j/runtime/impl/DefaultRuntime.java

@@ -379,14 +379,14 @@ private void addProvider(Provider provider, Map<IOType, Provider> providers) {
             if (provider.getPriority() <= existingProvider.getPriority()) {
                 if (existingProvider.getName().equals(provider.getName()))
                     throw new InitializeException(
-                        provider.getType() + " with name " + provider.getName() + " is already registered.");
-                logger.info("Ignoring provider {} {} with priority {} as lower priority than {} which has priority {}",
-                    provider.getType(), provider.getName(), provider.getPriority(), existingProvider.getName(),
-                    existingProvider.getPriority());
+                        provider.getType() + " with name " + provider.getName() + " (" + provider.getId() + ") is already registered.");
+                logger.info("Ignoring provider {} {} ({}) with priority {} as lower priority than {} which has priority {}",
+                    provider.getType(), provider.getName(), provider.getId(), provider.getPriority(),
+                    existingProvider.getName(), existingProvider.getPriority());
             } else {
-                logger.info("Replacing provider {} {} with priority {} with provider {} with higher priority {}",
-                    existingProvider.getType(), existingProvider.getName(), existingProvider.getPriority(),
-                    provider.getName(), provider.getPriority());
+                logger.info("Replacing provider {} {} ({}) with priority {} with provider {} ({}) with higher priority {}",
+                    existingProvider.getType(), existingProvider.getName(), existingProvider.getId(), existingProvider.getPriority(),
+                    provider.getName(), provider.getId(), provider.getPriority());
                 providers.put(provider.getType(), provider);
             }
         }