    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     */
    017    package org.apache.log4j.spi;
    018
    019    import org.apache.log4j.Appender;
    020    import org.apache.log4j.Category;
    021
    022    /**
    023     Listen to events occurring within a Hierarchy.
    024
    025     @since 1.2
    026
    027     */
    028    public interface HierarchyEventListener {
    029
    030        void addAppenderEvent(Category cat, Appender appender);
    031
    032        void removeAppenderEvent(Category cat, Appender appender);
    033    }