Java Path File Extention nio listFiles(String path, String extension)

Description

list Files

License

Apache License

Declaration

public static String[] listFiles(String path, String extension) throws IOException 

Method Source Code

//package com.java2s;
/*// ww w  . j  a v a2  s .  c o m
 * Copyright 2015 Futeh Kao
 *
 * Licensed 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.File;
import java.io.IOException;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.util.LinkedList;
import java.util.List;
import java.util.stream.Stream;

public class Main {
    private static final String[] EMPTY_FILE_LIST = new String[0];

    public static String[] listFiles(String path, String extension) throws IOException {
        String[] paths = EMPTY_FILE_LIST;
        if (path.endsWith("**")) {
            String dir = path.substring(0, path.length() - 2);
            if (Paths.get(dir).toFile().isDirectory()) {
                paths = listFiles(dir, extension, true);
            } else if (!Paths.get(dir).toFile().exists()) {
                throw new IOException("Directory " + dir + " does not exist");
            }
        } else if (path.endsWith("*")) {
            String dir = path.substring(0, path.length() - 1);
            if (Paths.get(dir).toFile().isDirectory()) {
                paths = listFiles(dir, extension, false);
            } else if (!Paths.get(dir).toFile().exists()) {
                throw new IOException("Directory " + dir + " does not exist");
            }
        } else {
            paths = getSingleFile(path, extension);
        }
        return paths;
    }

    private static String[] listFiles(String path, String extension, boolean recursive) throws IOException {
        List<String> directories = new LinkedList<>();
        List<String> list = new LinkedList<>();

        if (new File(path).isDirectory()) { // a directory
            directories.add(path);
        } else if (extension == null || path.endsWith(extension)) {
            list.add(path);
        }

        while (!directories.isEmpty()) {
            String parent = directories.remove(0);
            try (Stream<Path> stream = Files.list(Paths.get(parent))) {
                stream.forEach(f -> {
                    if (f.toFile().isDirectory()) {
                        if (recursive)
                            directories.add(f.toString());
                    } else if (extension == null || f.toString().endsWith(extension)) {
                        list.add(f.toString());
                    }
                });
            }
        }
        return list.toArray(new String[list.size()]);
    }

    private static String[] getSingleFile(String path, String extension) {
        String p = path.endsWith(extension) ? path : path + extension;
        if (path.startsWith("classpath:")) {
            return new String[] { p };
        } else {
            File f = new File(p);
            if (!f.isDirectory() && f.exists())
                return new String[] { p };

            return EMPTY_FILE_LIST;
        }
    }
}

Related

1. getTransformedOutputPath(Path input, String compressExtension, String outputDir)
2. hasExtensionIgnoreCase(Path path, String ext)
3. insertSuffixBeforeExtension(String path, String suffix)
4. listFile(final String path, final String extension)
5. listFiles(final Path path, final String... extensions)
6. removeExtension(final Path path)
7. removeExtension(Path file)
8. replaceExtensionWith(String toFilePath, String newExtension)
9. stripExtension(Path path, String extension)