Java tutorial
/* * 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. */ package org.apache.commons.configuration2.builder; import org.apache.commons.configuration2.event.Event; import org.apache.commons.configuration2.event.EventType; /** * <p> * A base event class for events generated by a {@link ConfigurationBuilder}. * </p> * <p> * Configuration builders can trigger a number of different events. All these * events are derived from this class. This event base class does not define any * additional properties. However, it defines that the event source must be a * {@code ConfigurationBuilder}. * </p> * * @version $Id$ * @since 2.0 */ public class ConfigurationBuilderEvent extends Event { /** The common super type for all events related to configuration builders. */ public static final EventType<ConfigurationBuilderEvent> ANY = new EventType<>(Event.ANY, "BUILDER"); /** * The specific event type for builder reset events. Events of this type are * generated each time the builder's {@code resetResult()} method is called. */ public static final EventType<ConfigurationBuilderEvent> RESET = new EventType<>(ANY, "RESET"); /** * The specific event type for configuration request events. Events of this * type are generated each time the builder's {@code getConfiguration()} * method is called (before the managed configuration is actually accessed * and the lock is acquired). This gives listeners the opportunity to * perform some checks which may invalidate the configuration, e.g. trigger * a reload check. <strong>Note:</strong> A listener must not call the * builder's {@code getConfiguration()} method - this will cause an * infinite loop! * * @see ConfigurationBuilder#getConfiguration() */ public static final EventType<ConfigurationBuilderEvent> CONFIGURATION_REQUEST = new EventType<>(ANY, "CONFIGURATION_REQUEST"); /** * Creates a new instance of {@code ConfigurationBuilderEvent} and sets * basic properties. * * @param source the {@code ConfigurationBuilder} object which triggered * this event (must not be <b>null</b>) * @param evType the type of this event (must not be <b>null</b>) * @throws IllegalArgumentException if a required parameter is null */ public ConfigurationBuilderEvent(final ConfigurationBuilder<?> source, final EventType<? extends ConfigurationBuilderEvent> evType) { super(source, evType); } /** * Returns the source of this event as a {@code ConfigurationBuilder}. * * @return the {@code ConfigurationBuilder} which generated this event */ @Override public ConfigurationBuilder<?> getSource() { return (ConfigurationBuilder<?>) super.getSource(); } }