    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 1002921 2010-09-30 01:33:38Z sebb $
    023     * @since Commons IO 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        public 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        public 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        public 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        public 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        public void handle(Exception ex);
    066
    067    }