Java tutorial
/* * ProActive Parallel Suite(TM): * The Open Source library for parallel and distributed * Workflows & Scheduling, Orchestration, Cloud Automation * and Big Data Analysis on Enterprise Grids & Clouds. * * Copyright (c) 2007 - 2017 ActiveEon * Contact: contact@activeeon.com * * This library is free software: you can redistribute it and/or * modify it under the terms of the GNU Affero General Public License * as published by the Free Software Foundation: version 3 of * the License. * * 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 Affero General Public License for more details. * * You should have received a copy of the GNU Affero General Public License * along with this program. If not, see <http://www.gnu.org/licenses/>. * * If needed, contact us to obtain a release under GPL Version 2 or 3 * or a different license than the AGPL. */ package org.ow2.proactive_grid_cloud_portal.cli.utils; import static org.ow2.proactive_grid_cloud_portal.cli.CLIException.REASON_IO_ERROR; import static org.ow2.proactive_grid_cloud_portal.cli.CLIException.REASON_OTHER; import java.io.File; import java.io.FileInputStream; import java.io.FileNotFoundException; import java.io.FileOutputStream; import java.io.IOException; import java.io.ObjectOutputStream; import java.io.OutputStream; import org.apache.commons.codec.digest.DigestUtils; import org.apache.commons.io.FileUtils; import org.ow2.proactive_grid_cloud_portal.cli.CLIException; public class FileUtility { public static String md5Checksum(File file) { try { return DigestUtils.md5Hex(new FileInputStream(file)); } catch (IOException ioe) { throw new CLIException(REASON_IO_ERROR, ioe); } } public static void writeStringToFile(File file, String content) { try { FileUtils.writeStringToFile(file, content); } catch (IOException ioe) { throw new CLIException(REASON_OTHER, ioe); } file.setReadable(true, true); file.setWritable(true, true); } public static String readFileToString(File file) { try { return FileUtils.readFileToString(file); } catch (IOException ioe) { throw new CLIException(REASON_IO_ERROR, ioe); } } public static byte[] byteArray(File file) { try { return FileUtils.readFileToByteArray(file); } catch (IOException ioe) { throw new CLIException(REASON_IO_ERROR, ioe); } } public static void writeByteArrayToFile(byte[] data, File file) { try { FileUtils.writeByteArrayToFile(file, data); } catch (IOException ioe) { throw new CLIException(REASON_IO_ERROR, ioe); } } public static void writeObjectToFile(Object object, File file) { FileOutputStream outputStream = null; try { outputStream = new FileOutputStream(file); ObjectOutputStream decorated = new ObjectOutputStream(outputStream); decorated.writeObject(object); decorated.flush(); } catch (IOException ioe) { throw new CLIException(REASON_IO_ERROR, ioe); } finally { if (outputStream != null) { try { outputStream.close(); } catch (IOException e) { // ignore } } } } public static OutputStream buildOutputStream(File file) throws IllegalArgumentException { if (file.exists() && !file.delete()) { throw new RuntimeException("Cannot delete the existing output file. " + file.getAbsolutePath()); } else { File parentFile = file.getParentFile(); if (parentFile == null) { throw new IllegalArgumentException( "Invalid pathname. Cannot determine the parent directory. " + file.getAbsolutePath()); } if (!(parentFile.exists() || parentFile.mkdirs())) { throw new RuntimeException( "Cannot create the non-existing parent directory of the file. " + file.getAbsolutePath()); } } try { return new FileOutputStream(file, true); } catch (FileNotFoundException e) { throw new IllegalArgumentException(e); } } private FileUtility() { } }