Java tutorial
/* * Created by Angel Leon (@gubatron), Alden Torres (aldenml) * Copyright (c) 2011, 2012, FrostWire(R). All rights reserved. * * This program is free software: you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation, either version 3 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program. If not, see <http://www.gnu.org/licenses/>. */ package com.frostwire.android.gui.util; import java.io.File; import java.io.IOException; import java.util.Collection; import java.util.HashSet; import java.util.Set; import java.util.Stack; import org.apache.commons.io.FilenameUtils; /** * @author gubatron * @author aldenml * */ public final class FileUtils { private FileUtils() { } /** * @param parentDir */ public static File createFolder(File parentDir, String folderName) { File f = new File(parentDir, folderName); if (!f.exists() || !f.isDirectory()) { f.mkdir(); } return f; } public static void deleteFolderRecursively(File folder) { if (folder != null && folder.isDirectory() && folder.canWrite()) { //delete your contents and recursively delete sub-folders File[] listFiles = folder.listFiles(); if (listFiles != null) { for (File f : listFiles) { if (f.isFile()) { f.delete(); } else if (f.isDirectory()) { deleteFolderRecursively(f); } } folder.delete(); } } } public static boolean deleteEmptyDirectoryRecursive(File directory) { // make sure we only delete canonical children of the parent file we // wish to delete. I have a hunch this might be an issue on OSX and // Linux under certain circumstances. // If anyone can test whether this really happens (possibly related to // symlinks), I would much appreciate it. String canonicalParent; try { canonicalParent = directory.getCanonicalPath(); } catch (IOException ioe) { return false; } if (!directory.isDirectory()) { return false; } boolean canDelete = true; File[] files = directory.listFiles(); for (int i = 0; i < files.length; i++) { try { if (!files[i].getCanonicalPath().startsWith(canonicalParent)) continue; } catch (IOException ioe) { canDelete = false; } if (!deleteEmptyDirectoryRecursive(files[i])) { canDelete = false; } } return canDelete ? directory.delete() : false; } public static String getValidFileName(String fileName) { String newFileName = fileName.replaceAll("[\\\\/:*?\"<>|\\[\\]]+", "_"); return newFileName; } /** Given a folder path it'll return all the files contained within it and it's subfolders * as a flat set of Files. * * Non-recursive implementation, up to 20% faster in tests than recursive implementation. :) * * @author gubatron * @param folder * @param extensions If you only need certain files filtered by their extensions, use this string array (without the "."). or set to null if you want all files. e.g. ["txt","jpg"] if you only want text files and jpegs. * * @return The set of files. */ public static Collection<File> getAllFolderFiles(File folder, String[] extensions) { Set<File> results = new HashSet<File>(); Stack<File> subFolders = new Stack<File>(); File currentFolder = folder; while (currentFolder != null && currentFolder.isDirectory() && currentFolder.canRead()) { File[] fs = null; try { fs = currentFolder.listFiles(); } catch (SecurityException e) { } if (fs != null && fs.length > 0) { for (File f : fs) { if (!f.isDirectory()) { if (extensions == null || FilenameUtils.isExtension(f.getName(), extensions)) { results.add(f); } } else { subFolders.push(f); } } } if (!subFolders.isEmpty()) { currentFolder = subFolders.pop(); } else { currentFolder = null; } } return results; } public static boolean isValidDirectory(File dir) { return dir != null && dir.exists() && dir.isDirectory(); } }