[maintenance events] Push notification listener

pom.xml

@@ -348,6 +348,14 @@
 						<include>src/test/java/redis/clients/jedis/commands/jedis/ClusterStreamsCommandsTest.java</include>
 						<include>src/test/java/redis/clients/jedis/commands/jedis/PooledStreamsCommandsTest.java</include>
 						<include>src/test/java/redis/clients/jedis/resps/StreamEntryDeletionResultTest.java</include>
+						<include>**/Maintenance*.java</include>
+						<include>**/Push*.java</include>
+						<include>**/Rebind*.java</include>
+						<include>src/test/java/redis/clients/jedis/upgrade/*.java</include>
+						<include>src/test/java/redis/clients/jedis/util/server/*.java</include>
+						<include>**/TimeoutOptions.java</include>
+						<include>**/*Handler.java</include>
+						<include>**/ConnectionTestHelper.java</include>
 					</includes>
 				</configuration>
 				<executions>

src/main/java/redis/clients/jedis/AbstractListenerHandler.java

@@ -0,0 +1,25 @@
+package redis.clients.jedis;
+
+import java.util.Collection;
+import java.util.List;
+import java.util.concurrent.CopyOnWriteArrayList;
+
+abstract class AbstractListenerHandler<T> implements ListenerHandler<T> {
+  private final List<T> listeners = new CopyOnWriteArrayList<>();
+
+  public void addListener(T listener) {
+    listeners.add(listener);
+  }
+
+  public void removeListener(T listener) {
+    listeners.remove(listener);
+  }
+
+  public void removeAllListeners() {
+    listeners.clear();
+  }
+
+  public Collection<T> getListeners() {
+    return listeners;
+  }
+}