| /* |
| * Licensed to the Apache Software Foundation (ASF) under one or more |
| * contributor license agreements. See the NOTICE file distributed with |
| * this work for additional information regarding copyright ownership. |
| * The ASF licenses this file to You under the Apache License, Version 2.0 |
| * (the "License"); you may not use this file except in compliance with |
| * the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| /* $Id$ */ |
| |
| package org.apache.fop.events; |
| |
| /** |
| * The EventBroadcaster is the central relay point for events. It receives events from various |
| * parts of the application and forwards them to any registered EventListener. |
| */ |
| public interface EventBroadcaster { |
| |
| /** |
| * Adds an event listener to the broadcaster. It is appended to the list of previously |
| * registered listeners (the order of registration defines the calling order). |
| * @param listener the listener to be added |
| */ |
| void addEventListener(EventListener listener); |
| |
| /** |
| * Removes an event listener from the broadcaster. If the event listener is not registered, |
| * nothing happens. |
| * @param listener the listener to be removed |
| */ |
| void removeEventListener(EventListener listener); |
| |
| /** |
| * Indicates whether any listeners have been registered with the broadcaster. |
| * @return true if listeners are present, false otherwise |
| */ |
| boolean hasEventListeners(); |
| |
| /** |
| * Broadcasts an event. This method is usually called from within the observed component. |
| * @param event the event to be broadcast |
| */ |
| void broadcastEvent(Event event); |
| |
| /** |
| * Returns an event producer instance for the given interface class. |
| * @param clazz the Class object identifying an {@link EventProducer} interface |
| * @return the event producer instance |
| */ |
| EventProducer getEventProducerFor(Class clazz); |
| |
| } |