http://xmlgraphics.apache.org/fop/: Apache FOP (Formatting Objects Processor) is the world's first print formatter driven by XSL formatting objects (XSL-FO) and the world's first output independent formatter. It is a Java application that reads a formatting object (FO) tree and renders the resulting pages to a specified output. Output formats currently supported include PDF, PCL, PS, AFP, TIFF, PNG, SVG, XML (area tree representation), Print, AWT and TXT. The primary output target is PDF. (Apache Software Foundation) 
/*
 * 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: CompositeEventListener.java 1734671 2016-03-12 05:39:53Z gadams $ */

package org.apache.fop.events;

import java.util.ArrayList;
import java.util.List;


EventListener implementation forwards events to possibly multiple other EventListeners.

/**
 * EventListener implementation forwards events to possibly multiple other EventListeners.
 */
public class CompositeEventListener implements EventListener {

    private List<EventListener> listeners = new ArrayList<EventListener>();

    
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).

Params:
  • listener – the listener to be added
/**
     * 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
     */
    public synchronized void addEventListener(EventListener listener) {
        this.listeners.add(listener);
    }

    
Removes an event listener from the broadcaster. If the event listener is not registered,
nothing happens.

Params:
  • listener – the listener to be removed
/**
     * Removes an event listener from the broadcaster. If the event listener is not registered,
     * nothing happens.
     * @param listener the listener to be removed
     */
    public synchronized void removeEventListener(EventListener listener) {
        this.listeners.remove(listener);
    }

    
Indicates whether any listeners have been registered with the broadcaster.

Returns:true if listeners are present, false otherwise
/**
     * Indicates whether any listeners have been registered with the broadcaster.
     * @return true if listeners are present, false otherwise
     */
    public synchronized boolean hasEventListeners() {
        return !listeners.isEmpty();
    }

    
{@inheritDoc } 
/** {@inheritDoc } */
    public synchronized void processEvent(Event event) {
        for (EventListener listener : listeners) {
            listener.processEvent(event);
        }
    }

}