KEYCLOAK-1062 Document how to configure listeners

examples/providers/event-listener-sysout/README.md

@@ -5,3 +5,13 @@ To deploy copy target/event-listener-sysout-example.jar to standalone/configurat
 Then start (or restart) the server. Once started open the admin console, select your realm, then click on Events, 
 followed by config. Click on Listeners select box, then pick sysout from the dropdown. After this try to logout and 
 login again to see events printed to System.out.
+
+The example event listener can be configured to exclude certain events, for example to exclude REFRESH_TOKEN and
+CODE_TO_TOKEN events add the following to keycloak-server.json:
+
+    ...
+    "eventsListener": {
+        "sysout" {
+            "exclude": [ "REFRESH_TOKEN", "CODE_TO_TOKEN" ]
+        }
+    }

examples/providers/event-listener-sysout/src/main/java/org/keycloak/examples/providers/events/SysoutEventListenerProviderFactory.java

@@ -24,10 +24,10 @@ public class SysoutEventListenerProviderFactory implements EventListenerProvider
 
     @Override
     public void init(Config.Scope config) {
-        String excludes = config.get("excludes");
+        String[] excludes = config.getArray("excludes");
         if (excludes != null) {
-            excludedEvents = new HashSet<EventType>();
-            for (String e : excludes.split(",")) {
+            excludedEvents = new HashSet<>();
+            for (String e : excludes) {
                 excludedEvents.add(EventType.valueOf(e));
             }
         }