Java tutorial
/* * Created on 19/giu/2010 * * Copyright 2010 by Andrea Vacondio (andrea.vacondio@gmail.com). * * This file is part of the Sejda source code * * This program 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, 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 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/>. */ package org.sejda.core.support.io; import static java.util.Optional.of; import static org.apache.commons.lang3.StringUtils.isBlank; import static org.sejda.model.output.ExistingOutputPolicy.FAIL; import static org.sejda.model.output.ExistingOutputPolicy.SKIP; import java.io.File; import java.io.FileInputStream; import java.io.IOException; import java.io.InputStream; import java.io.OutputStream; import java.util.Map; import java.util.Map.Entry; import java.util.zip.ZipEntry; import java.util.zip.ZipOutputStream; import org.apache.commons.io.FileUtils; import org.apache.commons.io.IOUtils; import org.sejda.model.output.ExistingOutputPolicy; import org.slf4j.Logger; import org.slf4j.LoggerFactory; /** * Utility class responsible for writing the input files to the output destination * * @author Andrea Vacondio * */ final class OutputWriterHelper { private static final Logger LOG = LoggerFactory.getLogger(OutputWriterHelper.class); private OutputWriterHelper() { // util class } /** * Moves the input file contained in the input map (single file) to the output file * * @param files * @param outputFile * @param existingOutputPolicy * policy to use if an output that already exists is found * @throws IOException */ static void moveToFile(Map<String, File> files, File outputFile, ExistingOutputPolicy existingOutputPolicy) throws IOException { if (outputFile.exists() && !outputFile.isFile()) { throw new IOException(String.format("Wrong output destination %s, must be a file.", outputFile)); } if (files.size() != 1) { throw new IOException( String.format("Wrong files map size %d, must be 1 to copy to the selected destination %s", files.size(), outputFile)); } for (Entry<String, File> entry : files.entrySet()) { moveFile(entry.getValue(), outputFile, of(existingOutputPolicy).filter(p -> p != SKIP).orElseGet(() -> { LOG.debug("Cannot use {} output policy for single output, replaced with {}", SKIP, FAIL); return FAIL; })); } } /** * Moves the input files to the output directory * * @param files * @param outputDirectory * @param existingOutputPolicy * policy to use if an output that already exists is found * @throws IOException */ static void moveToDirectory(Map<String, File> files, File outputDirectory, ExistingOutputPolicy existingOutputPolicy) throws IOException { if (!outputDirectory.isDirectory()) { throw new IOException( String.format("Wrong output destination %s, must be a directory.", outputDirectory)); } if (!outputDirectory.exists() && !outputDirectory.mkdirs()) { throw new IOException(String.format("Unable to make destination directory tree %s.", outputDirectory)); } for (Entry<String, File> entry : files.entrySet()) { if (isBlank(entry.getKey())) { throw new IOException(String.format( "Unable to move %s to the output directory, no output name specified.", entry.getValue())); } moveFile(entry.getValue(), new File(outputDirectory, entry.getKey()), existingOutputPolicy); } } /** * Moves the input file to the output file * * @param input * input file * @param output * output file * @param existingOutputPolicy * policy to use if an output that already exists is found * @throws IOException */ private static void moveFile(File input, File output, ExistingOutputPolicy existingOutputPolicy) throws IOException { if (output.exists()) { switch (existingOutputPolicy) { case OVERWRITE: LOG.debug("Moving {} to {}.", input, output); FileUtils.deleteQuietly(output); FileUtils.moveFile(input, output); break; case SKIP: LOG.info("Skipping already existing output file {}", output); break; default: throw new IOException(String.format( "Unable to write %s to the already existing file destination %s. (policy is %s)", input, output, existingOutputPolicy)); } } else { LOG.debug("Moving {} to {}.", input, output); FileUtils.moveFile(input, output); } } /** * Copy the populated file map to a zip output stream * * @param files * @param out * @throws IOException */ static void copyToStreamZipped(Map<String, File> files, OutputStream out) throws IOException { ZipOutputStream zipOut = new ZipOutputStream(out); for (Entry<String, File> entry : files.entrySet()) { FileInputStream input = null; if (isBlank(entry.getKey())) { throw new IOException(String.format( "Unable to copy %s to the output stream, no output name specified.", entry.getValue())); } try { input = new FileInputStream(entry.getValue()); zipOut.putNextEntry(new ZipEntry(entry.getKey())); LOG.debug("Copying {} to zip stream {}.", entry.getValue(), entry.getKey()); IOUtils.copy(input, zipOut); } finally { IOUtils.closeQuietly(input); delete(entry.getValue()); } } IOUtils.closeQuietly(zipOut); } /** * Copies the contents of the file to the specified outputstream, without zipping or applying any other changes. * * @param file * @param out * @throws IOException */ static void copyToStream(File file, OutputStream out) throws IOException { InputStream in = null; try { in = new FileInputStream(file); IOUtils.copy(in, out); } finally { IOUtils.closeQuietly(in); delete(file); } } private static void delete(File file) { if (!file.delete()) { LOG.warn("Unable to delete temporary file {}", file); } } }