Here you can find the source of getFiles(String sourceDirPath, FilenameFilter filter, Comparator
public static List<String> getFiles(String sourceDirPath, FilenameFilter filter, Comparator<String> comparator) throws IOException
//package com.java2s; /*/*www . ja va2s .c o m*/ * * Licensed to the Apache Software Foundation (ASF) under one * or more contributor license agreements. See the NOTICE file * distributed with this work for additional information * regarding copyright ownership. The ASF licenses this file * to you under the Apache License, Version 2.0 (the * "License"); you may not use this file except in compliance * with the License. You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, * software distributed under the License is distributed on an * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY * KIND, either express or implied. See the License for the * specific language governing permissions and limitations * under the License. * */ import java.io.*; import java.util.*; public class Main { public static final String FILE_SEPARATOR = File.separator; public static List<String> getFiles(String sourceDirPath, FilenameFilter filter, Comparator<String> comparator) throws IOException { File file = new File(sourceDirPath); if (!file.exists()) { throw new IOException("Directory " + sourceDirPath + " does not exist"); } if (!file.isDirectory()) { throw new IOException("File " + sourceDirPath + " is not a directory"); } String[] files = file.list(filter); Arrays.sort(files, comparator); List<String> fullPaths = new LinkedList<>(); for (int i = 0; i < files.length; i++) { String fullPath = sourceDirPath + FILE_SEPARATOR + files[i]; fullPaths.add(fullPath); } return fullPaths; } }