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.commons.io.input;
018    
019    /**
020     * Listener for events from a {@link Tailer}.
021     *
022     * @version $Id: TailerListener.java 1304052 2012-03-22 20:55:29Z ggregory $
023     * @since 2.0
024     */
025    public interface TailerListener {
026    
027        /**
028         * The tailer will call this method during construction,
029         * giving the listener a method of stopping the tailer.
030         * @param tailer the tailer.
031         */
032        void init(Tailer tailer);
033    
034        /**
035         * This method is called if the tailed file is not found.
036         * <p>
037         * <b>Note:</b> this is called from the tailer thread.
038         */
039        void fileNotFound();
040    
041        /**
042         * Called if a file rotation is detected.
043         *
044         * This method is called before the file is reopened, and fileNotFound may
045         * be called if the new file has not yet been created.
046         * <p>
047         * <b>Note:</b> this is called from the tailer thread.
048         */
049        void fileRotated();
050    
051        /**
052         * Handles a line from a Tailer.
053         * <p>
054         * <b>Note:</b> this is called from the tailer thread.
055         * @param line the line.
056         */
057        void handle(String line);
058    
059        /**
060         * Handles an Exception .
061         * <p>
062         * <b>Note:</b> this is called from the tailer thread.
063         * @param ex the exception.
064         */
065        void handle(Exception ex);
066    
067    }