    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 *      https://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
    018package org.apache.commons.io.input;
    019
    020/**
    021 * Listens to events from a {@link Tailer}.
    022 *
    023 * @since 2.0
    024 */
    025public interface TailerListener {
    026
    027    /**
    028     * Called if the tailed file is not found.
    029     * <p>
    030     * <strong>Note:</strong> this is called from the tailer thread.
    031     * </p>
    032     */
    033    void fileNotFound();
    034
    035    /**
    036     * Called if a file rotation is detected.
    037     *
    038     * This method is called before the file is reopened, and fileNotFound may be called if the new file has not yet been created.
    039     * <p>
    040     * <strong>Note:</strong> Called from the tailer thread.
    041     * </p>
    042     */
    043    void fileRotated();
    044
    045    /**
    046     * Called when an Exception is thrown.
    047     * <p>
    048     * <strong>Note:</strong> Called from the tailer thread.
    049     * </p>
    050     *
    051     * @param e the exception.
    052     */
    053    void handle(Exception e);
    054
    055    /**
    056     * Called when a line is read.
    057     * <p>
    058     * <strong>Note:</strong> Called from the tailer thread.
    059     * </p>
    060     *
    061     * @param line the line.
    062     */
    063    void handle(String line);
    064
    065    /**
    066     * Called during construction, giving the listener a method of stopping the tailer.
    067     *
    068     * @param tailer the tailer.
    069     */
    070    void init(Tailer tailer);
    071}