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.Event; 020import org.apache.commons.configuration2.event.EventType; 021 022/** 023 * <p> 024 * A base event class for events generated by a {@link ConfigurationBuilder}. 025 * </p> 026 * <p> 027 * Configuration builders can trigger a number of different events. All these 028 * events are derived from this class. This event base class does not define any 029 * additional properties. However, it defines that the event source must be a 030 * {@code ConfigurationBuilder}. 031 * </p> 032 * 033 * @since 2.0 034 */ 035public class ConfigurationBuilderEvent extends Event 036{ 037 /** The common super type for all events related to configuration builders. */ 038 public static final EventType<ConfigurationBuilderEvent> ANY = 039 new EventType<>(Event.ANY, "BUILDER"); 040 041 /** 042 * The specific event type for builder reset events. Events of this type are 043 * generated each time the builder's {@code resetResult()} method is called. 044 */ 045 public static final EventType<ConfigurationBuilderEvent> RESET = 046 new EventType<>(ANY, "RESET"); 047 048 /** 049 * The specific event type for configuration request events. Events of this 050 * type are generated each time the builder's {@code getConfiguration()} 051 * method is called (before the managed configuration is actually accessed 052 * and the lock is acquired). This gives listeners the opportunity to 053 * perform some checks which may invalidate the configuration, e.g. trigger 054 * a reload check. <strong>Note:</strong> A listener must not call the 055 * builder's {@code getConfiguration()} method - this will cause an 056 * infinite loop! 057 * 058 * @see ConfigurationBuilder#getConfiguration() 059 */ 060 public static final EventType<ConfigurationBuilderEvent> CONFIGURATION_REQUEST = 061 new EventType<>(ANY, 062 "CONFIGURATION_REQUEST"); 063 064 /** 065 * Creates a new instance of {@code ConfigurationBuilderEvent} and sets 066 * basic properties. 067 * 068 * @param source the {@code ConfigurationBuilder} object which triggered 069 * this event (must not be <b>null</b>) 070 * @param evType the type of this event (must not be <b>null</b>) 071 * @throws IllegalArgumentException if a required parameter is null 072 */ 073 public ConfigurationBuilderEvent(final ConfigurationBuilder<?> source, 074 final EventType<? extends ConfigurationBuilderEvent> evType) 075 { 076 super(source, evType); 077 } 078 079 /** 080 * Returns the source of this event as a {@code ConfigurationBuilder}. 081 * 082 * @return the {@code ConfigurationBuilder} which generated this event 083 */ 084 @Override 085 public ConfigurationBuilder<?> getSource() 086 { 087 return (ConfigurationBuilder<?>) super.getSource(); 088 } 089}