001/*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements.  See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License.  You may obtain a copy of the License at
008 *
009 *     http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017package org.apache.commons.configuration2.builder;
018
019import org.apache.commons.configuration2.event.EventListenerList;
020
021/**
022 * <p>
023 * Definition of an interface that is evaluated by a
024 * {@link ConfigurationBuilder} to initialize event listeners.
025 * </p>
026 * <p>
027 * This interface allows a convenient initialization of a configuration builder
028 * with event listeners to be registered at the managed configuration object.
029 * The {@code configure()} method of {@link BasicConfigurationBuilder} checks
030 * whether a parameters object passed to it implements this interface. If this
031 * is the case, all event listeners defined by the object are added to the
032 * internal list managed by the builder. They are then automatically registered
033 * at the managed configuration when it is created. When using a corresponding
034 * implementation the configuration of event listeners can be done in the same
035 * fluent API style as the other initialization of the configuration builder.
036 * </p>
037 *
038 * @since 2.0
039 */
040public interface EventListenerProvider
041{
042    /**
043     * Returns an {@code EventListenerList} object with information about event
044     * listener registrations. All listeners contained in this object are added
045     * to the processing {@code ConfigurationBuilder}.
046     *
047     * @return the {@code EventListenerList} with event listener registrations
048     *         (must not be <b>null</b>)
049     */
050    EventListenerList getListeners();
051}