Java tutorial
/* Copyright (c) 2011 Danish Maritime Authority * * This library is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public * License as published by the Free Software Foundation; either * version 3 of the License, or (at your option) any later version. * * This library 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 * Lesser General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this library. If not, see <http://www.gnu.org/licenses/>. */ package dk.dma.msiproxy.common.repo; import dk.dma.msiproxy.common.settings.annotation.Setting; import org.apache.commons.io.FileUtils; import org.apache.commons.io.FilenameUtils; import org.apache.commons.lang.StringUtils; import org.slf4j.Logger; import javax.annotation.PostConstruct; import javax.annotation.PreDestroy; import javax.ejb.Lock; import javax.ejb.LockType; import javax.enterprise.context.ApplicationScoped; import javax.imageio.ImageIO; import javax.inject.Inject; import javax.inject.Named; import java.awt.Graphics2D; import java.awt.geom.AffineTransform; import java.awt.image.BufferedImage; import java.io.BufferedReader; import java.io.File; import java.io.IOException; import java.io.InputStreamReader; import java.nio.file.Files; import java.nio.file.Path; import java.util.HashSet; import java.util.Set; import java.util.concurrent.ExecutionException; import java.util.concurrent.ExecutorService; import java.util.concurrent.Executors; /** * Creates thumbnails * <p> * An ExecutorService is used to limit load on the system * </p> */ @Named @ApplicationScoped @Lock(LockType.READ) public class ThumbnailService { private static final int EXECUTOR_POOL_SIZE = 2; @Inject Logger log; @Inject @Setting(value = "vipsPath") String vipsCmd; Set<String> vipsFileTypes = new HashSet<>(); @Inject FileTypes fileTypes; private ExecutorService processPool; @PostConstruct private void init() { processPool = Executors.newFixedThreadPool(EXECUTOR_POOL_SIZE); // Enlist image types supported by vips (avoid gif) vipsFileTypes.add("image/bmp"); vipsFileTypes.add("image/jpeg"); vipsFileTypes.add("image/jpg"); vipsFileTypes.add("image/tiff"); vipsFileTypes.add("image/tif"); vipsFileTypes.add("image/png"); } @PreDestroy private void closeDown() { if (processPool != null && !processPool.isShutdown()) { processPool.shutdown(); processPool = null; } } /** * Returns or creates the a thumbnail for the given file if it is an image. * Otherwise, null is returned * * @param file the file to create a thumbnail for * @param size the size of the thumbnail * @return the thumbnail file or null if none was found or created */ public Path getThumbnail(final Path file, final IconSize size) { // Check that the file exists if (!Files.isRegularFile(file)) { log.warn("File does not exist: " + file); return null; } final String type = fileTypes.getContentType(file); if (type == null || !type.startsWith("image")) { log.debug("File not an image: " + file); return null; } // Submit the thumbnail creation job to the process pool. // Please note, this is used as a way of restricting load on the system, // not per se as a way of executing the task asynchronously. try { return processPool.submit(() -> createThumbnail(file, type, size)).get(); } catch (InterruptedException | ExecutionException e) { log.debug("Error creating thumbnail"); } return null; } /** * Returns or creates the a thumbnail for the given file if it is an image. * Otherwise, null is returned * * @param file the file to create a thumbnail for * @param type the type of image * @param size the size of the thumbnail * @return the thumbnail file or null if none was found or created */ public Path createThumbnail(Path file, String type, IconSize size) { try { // Construct the thumbnail name by appending "_thumb_size" to the file name String thumbName = String.format("%s_thumb_%d.%s", FilenameUtils.removeExtension(file.getFileName().toString()), size.getSize(), FilenameUtils.getExtension(file.getFileName().toString())); // Check if the thumbnail already exists Path thumbFile = file.getParent().resolve(thumbName); if (Files.isRegularFile(thumbFile) && Files.getLastModifiedTime(thumbFile).toMillis() >= Files .getLastModifiedTime(file).toMillis()) { return thumbFile; } // Check whether to use VIPS or java if (StringUtils.isNotBlank(vipsCmd) && vipsFileTypes.contains(type.toLowerCase())) { // Use VIPS createThumbnailUsingVips(file, thumbFile, size); } else { // Use java APIs createThumbnailUsingJava(file, thumbFile, size); } return thumbFile; } catch (Throwable e) { // Alas, no thumbnail return null; } } /** * Creates a thumbnail for the image file using libvips * * @param file the image file * @param thumbFile the resulting thumbnail file * @param size the size of the thumbnail */ private void createThumbnailUsingVips(Path file, Path thumbFile, IconSize size) throws IOException { try { // Example command: vipsthumbnail -s 64 -p bilinear -o thumb.png image2.jpg final Process proc = new ProcessBuilder(vipsCmd, "-s", String.valueOf(size.getSize()), "-p", "bilinear", "-o", thumbFile.toString(), file.toString()).directory(new File(System.getProperty("user.dir"))) .inheritIO().start(); BufferedReader br = new BufferedReader(new InputStreamReader(proc.getInputStream())); String line; while ((line = br.readLine()) != null) { log.debug(line); } //Wait to get exit value int exitValue = proc.waitFor(); log.debug("Exit Value is " + exitValue); // Update the timestamp of the thumbnail file to match the change date of the image file Files.setLastModifiedTime(thumbFile, Files.getLastModifiedTime(file)); } catch (IOException | InterruptedException e) { log.error("Error creating thumbnail for image " + file, e); throw new IOException(e); } } /** * Creates a thumbnail for the image file using plain old java * @param file the image file * @param thumbFile the resulting thumbnail file * @param size the size of the thumbnail */ private void createThumbnailUsingJava(Path file, Path thumbFile, IconSize size) throws IOException { try { BufferedImage image = ImageIO.read(file.toFile()); int w = image.getWidth(); int h = image.getHeight(); // Never scale up if (w <= size.getSize() && h <= size.getSize()) { FileUtils.copyFile(file.toFile(), thumbFile.toFile()); } else { // Compute the scale factor double dx = (double) size.getSize() / (double) w; double dy = (double) size.getSize() / (double) h; double d = Math.min(dx, dy); // Create the thumbnail BufferedImage thumbImage = new BufferedImage((int) Math.round(w * d), (int) Math.round(h * d), BufferedImage.TYPE_INT_RGB); Graphics2D g2d = thumbImage.createGraphics(); AffineTransform at = AffineTransform.getScaleInstance(d, d); g2d.drawRenderedImage(image, at); g2d.dispose(); // Save the thumbnail String fileName = thumbFile.getFileName().toString(); ImageIO.write(thumbImage, FilenameUtils.getExtension(fileName), thumbFile.toFile()); // Releas resources image.flush(); thumbImage.flush(); } // Update the timestamp of the thumbnail file to match the change date of the image file Files.setLastModifiedTime(thumbFile, Files.getLastModifiedTime(file)); } catch (Exception e) { log.error("Error creating thumbnail for image " + file, e); throw new IOException(e); } } }