1 /* 2 * Licensed to the Apache Software Foundation (ASF) under one or more 3 * contributor license agreements. See the NOTICE file distributed with 4 * this work for additional information regarding copyright ownership. 5 * The ASF licenses this file to You under the Apache License, Version 2.0 6 * (the "License"); you may not use this file except in compliance with 7 * the License. You may obtain a copy of the License at 8 * 9 * http://www.apache.org/licenses/LICENSE-2.0 10 * 11 * Unless required by applicable law or agreed to in writing, software 12 * distributed under the License is distributed on an "AS IS" BASIS, 13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 14 * See the License for the specific language governing permissions and 15 * limitations under the License. 16 */ 17 package org.apache.commons.fileupload2.core; 18 19 /** 20 * Receives progress information. May be used to display a progress bar. 21 */ 22 @FunctionalInterface 23 public interface ProgressListener { 24 25 /** 26 * Nop implementation. 27 */ 28 ProgressListener NOP = (bytesRead, contentLength, items) -> { 29 // nop 30 }; 31 32 /** 33 * Updates the listeners status information. 34 * 35 * @param bytesRead The total number of bytes, which have been read so far. 36 * @param contentLength The total number of bytes, which are being read. May be -1, if this number is unknown. 37 * @param items The number of the field, which is currently being read. (0 = no item so far, 1 = first item is being read, ...) 38 */ 39 void update(long bytesRead, long contentLength, int items); 40 41 }