    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 */
    017package org.apache.commons.fileupload2.core;
    018
    019/**
    020 * Receives progress information. May be used to display a progress bar.
    021 */
    022@FunctionalInterface
    023public interface ProgressListener {
    024
    025    /**
    026     * Nop implementation.
    027     */
    028    ProgressListener NOP = (bytesRead, contentLength, items) -> {
    029        // nop
    030    };
    031
    032    /**
    033     * Updates the listeners status information.
    034     *
    035     * @param bytesRead     The total number of bytes, which have been read so far.
    036     * @param contentLength The total number of bytes, which are being read. May be -1, if this number is unknown.
    037     * @param items         The number of the field, which is currently being read. (0 = no item so far, 1 = first item is being read, ...)
    038     */
    039    void update(long bytesRead, long contentLength, int items);
    040
    041}