/* * Copyright 1999-2005 The Apache Software Foundation. *  * Licensed 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.log4j.spi;import org.apache.log4j.*;/**   Listen to events occuring within a {@link   org.apache.log4j.Hierarchy Hierarchy}.   @author Ceki Gülcü   @since 1.2    */public interface HierarchyEventListener {   //public  //void categoryCreationEvent(Category cat);  public  void addAppenderEvent(Category cat, Appender appender);  public  void removeAppenderEvent(Category cat, Appender appender);}