com.agapsys.web.toolkit.utils.FileUtils Maven / Gradle / Ivy

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/*
 * Copyright 2015-2016 Agapsys Tecnologia Ltda-ME.
 *
 * 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.
 */
package com.agapsys.web.toolkit.utils;

import java.io.File;
import java.io.FileNotFoundException;
import java.io.IOException;

/**
 * File Handling utilities
 */
public class FileUtils {

    protected FileUtils() {}

    public static class AccessError extends Exception {

        public AccessError() {
        }

        public AccessError(String message) {
            super(message);
        }

        public AccessError(String message, Throwable cause) {
            super(message, cause);
        }

        public AccessError(Throwable cause) {
            super(cause);
        }
    }

    /**
     * Default folder delimiter.
     */
    public static final String FOLDER_DELIMITER;

    /**
     * Current user folder.
     */
    public static final File USER_HOME;

    /**
     * Default temporary folder.
     */
    public static final File DEFAULT_TEMPORARY_FOLDER;

    /**
     * Current Operating System.
     */
    public static final String OS_NAME;

    static {
        FOLDER_DELIMITER = System.getProperty("file.separator");
        USER_HOME = new File(System.getProperty("user.home"));
        DEFAULT_TEMPORARY_FOLDER = new File(System.getProperty("java.io.tmpdir"));
        OS_NAME = System.getProperty("os.name");
    }

    /**
     * @return a file representing a given path. If directory hierarchy does not exist, they will be created.
     *
     * @param path directory path
     * @throws AccessError if directory hierarchy does not exist and it was not possible to create it.
     * @throws IllegalArgumentException if given path points to a file instead of a directory.
     */
    public static File getOrCreateDirectory(String path) throws AccessError, IllegalArgumentException {
        File folder = new File(path);
        if (!folder.exists()) {
            if (!folder.mkdirs())
                throw new AccessError(String.format("cannot create/access '%s'", path));

        } else if (!folder.isDirectory()) {
            throw new IllegalArgumentException(String.format("Path '%s' is a file", path));
        }

        if (OS_NAME.toLowerCase().contains("win") && folder.getName().startsWith(".")) {
            try {
                Runtime.getRuntime().exec("attrib +H " + folder.getAbsolutePath());
            } catch (IOException ignore) {}
        }
        return folder;
    }

    /**
     * Deletes a file. If given file is a folder, delete its contents also.
     *
     * @param file file to delete.
     * @throws FileNotFoundException if given file does not exist.
     */
    public static void deleteFile(File file) throws FileNotFoundException {
        if (file == null)
            throw new IllegalArgumentException("Null file");

        if (!file.exists())
            throw new FileNotFoundException(String.format("File not found: %s", file.getAbsolutePath()));

        if (file.isDirectory()) {
            File[] files = file.listFiles();

            for (File tmpFile : files) {
                deleteFile(tmpFile); // recursive
            }

            file.delete();
        } else {
            file.delete();
        }
    }

    /**
     * Returns a generated non-existent file.
     *
     * @param parentDirectory parent directory.
     * @param nameLength filename length.
     * @param maxAttempts maximum number of attempts trying to get a random non-existent file before an exception is thrown.
     * @return non-existent file with random name.
     * @throws FileNotFoundException if a non-existent file could not be found.
     */
    public static File getRandomNonExistentFile(File parentDirectory, int nameLength, int maxAttempts) throws FileNotFoundException {
        char[] chars = "abcdefghijklmnopqrstuvwxyz0123456789".toCharArray();

        if (parentDirectory == null)
            throw new IllegalArgumentException("Parent directory cannot be null");

        if (nameLength < 1)
            throw new IllegalArgumentException("Name length must be greater than 1");

        if (maxAttempts < 1)
            throw new IllegalArgumentException("Maximum attempts must be greater than 1");

        File file;
        int attempts = 0;

        while (true) {
            if (attempts >= maxAttempts)
                throw new FileNotFoundException(String.format("It was not possible to generate a randon non-existent file after %d attempts", maxAttempts));

            file = new File(parentDirectory, StringUtils.getRandom(nameLength, chars));

            if (!file.exists())
                return file;

            attempts++;
        }
    }

}