Java tutorial
/* Copyright 2015 Mark Otway 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.otway.picasasync.syncutil; import com.google.gdata.data.photos.PhotoEntry; import com.google.gdata.util.ServiceException; import com.otway.picasasync.config.Settings; import com.otway.picasasync.metadata.ImageInformation; import org.apache.commons.io.FileUtils; import org.apache.log4j.Logger; import org.apache.sanselan.ImageReadException; import java.io.File; import java.io.FileInputStream; import java.io.IOException; import java.time.Instant; import java.time.LocalDateTime; import java.time.ZoneId; import java.time.temporal.ChronoUnit; import static com.otway.picasasync.utils.TimeUtils.getTimeFromMS; /** * File to Determine the change state of a local/remote image pair */ public class ImageSync { public enum UpdateAction { none, download, upload } // Time difference allowed between local and remote // before triggering an upload or download private final int TIME_DELTA_SECS = 5; private final PhotoEntry remotePhoto; private final File localFile; private String localMd5CheckSum; public String getLocalMd5CheckSum() { return localMd5CheckSum; } public PhotoEntry getRemotePhoto() { return remotePhoto; } public File getLocalFile() { return localFile; } public ImageSync(PhotoEntry remotePhoto, File localFileName) { this.remotePhoto = remotePhoto; this.localFile = localFileName; } // Checks that neither the local file or remote file are newer // than a certain date. If either is newer, we'll consider it // for upload/download. If not, we'll skip it. public boolean newerThan(LocalDateTime threshold) throws ServiceException { boolean localFileExists = localFile.exists(); if (localFileExists) { LocalDateTime localTimeStamp = getTimeFromMS(localFile.lastModified()); // There's a local file. See if it's newer if (localTimeStamp.isAfter(threshold)) return true; } if (remotePhoto != null) { LocalDateTime remoteTimeStamp = LocalDateTime.ofInstant(remotePhoto.getTimestamp().toInstant(), ZoneId.systemDefault()); // There's a remote file. See if it's newer if (remoteTimeStamp.isAfter(threshold)) return true; } return false; } // Currently unused, but if Picasa ever fixed it so the checksum was // actually updated whenever an image changes, we could use this. private void generateMd5CheckSum() { final boolean USE_CHECKSUMS = false; if (USE_CHECKSUMS) { try { FileInputStream fis = new FileInputStream(localFile); localMd5CheckSum = org.apache.commons.codec.digest.DigestUtils.md5Hex(fis); fis.close(); } catch (Exception ex) { log.warn("Unable to calculate MD5 checksum", ex); } } } /* * Figure out what we actually need to do. */ public UpdateAction evaluateAction(Settings settings, boolean isAutoBackup) { boolean canDownloadNew = settings.getDownloadNew(); boolean canDownloadChanged = settings.getDownloadChanged(); boolean canUploadNew = settings.getUploadNew(); boolean canUploadChanged = settings.getUploadChanged(); if (isAutoBackup) { canDownloadNew = settings.getAutoBackupDownload(); canUploadChanged = canUploadNew = settings.getAutoBackupUpload(); } UpdateAction action = UpdateAction.none; boolean hasLocalFile = localFile.exists(); boolean hasRemoteFile = remotePhoto != null; boolean isNewFile = false; if (hasLocalFile) generateMd5CheckSum(); if (hasLocalFile && hasRemoteFile) { // We have both. See if they're the same... if (remotePhoto.getChecksum() != null && remotePhoto.getChecksum().equals(localMd5CheckSum)) { // We have an MD5 checksum, and it matches. Happy days. log.debug("MD5 checksum matched. No action required"); action = UpdateAction.none; } else { // There's a remote photo. See which is newer. LocalDateTime localMod = getTimeFromMS(localFile.lastModified()); LocalDateTime remoteMod = getTimeFromMS(remotePhoto.getUpdated().getValue()); long seconds = ChronoUnit.SECONDS.between(remoteMod, localMod); if (Math.abs(seconds) > TIME_DELTA_SECS) { if (seconds > 0) { log.info("Image " + localFile.getName() + " is " + seconds + "s newer than remote image, so will be uploaded"); action = UpdateAction.upload; } else { log.info("Image " + localFile.getName() + " is " + seconds + "s older than remote image, so will be downloaded"); action = UpdateAction.download; } } } } else { if (hasLocalFile) { // No remote file. It's a new file to upload action = UpdateAction.upload; isNewFile = true; } else if (hasRemoteFile) { // No local file. It's a new file to download action = UpdateAction.download; isNewFile = true; } } // Now we've established what the action we'd *like* to // do is, now see if we're actually allowed to do it. if (action == UpdateAction.download) { if (isNewFile) { if (!canDownloadNew) action = UpdateAction.none; } else { if (!canDownloadChanged) action = UpdateAction.none; } } else { if (isNewFile) { if (!canUploadNew) action = UpdateAction.none; } else { if (!canUploadChanged) action = UpdateAction.none; } } return action; } // TODO: Probably not used. Maybe refactor - if we care about image size private static final Logger log = Logger.getLogger(ImageSync.class); private boolean localCopyNeedsUpdating(PhotoEntry photo, File localPath) throws ImageReadException, IOException, ServiceException { boolean updateLocal = false; if (localPath.exists()) { LocalDateTime localMod = getTimeFromMS(localPath.lastModified()); LocalDateTime remoteMod = getTimeFromMS(photo.getUpdated().getValue()); long seconds = ChronoUnit.SECONDS.between(localMod, remoteMod); if (Math.abs(seconds) > 1) return true; long localFileSize = localPath.length(); long remoteFileSize = photo.getSize(); if (localFileSize != remoteFileSize) { log.info(String.format( "File sizes are different: (local %s vs remote %s). Local file will be updated.", FileUtils.byteCountToDisplaySize(localFileSize), FileUtils.byteCountToDisplaySize(remoteFileSize))); return true; } ImageInformation localInfo = ImageInformation.safeReadImageInformation(localPath); if (localInfo != null) { Integer rotation = photo.getRotation(); if (rotation != null) log.info("PhotoEntry rotation was set!"); // Make sure we take into account the rotation of the image when comparing width/height long localWidth = localInfo.getWidthHeightTransposed() ? localInfo.getHeight() : localInfo.getWidth(); long localHeight = localInfo.getWidthHeightTransposed() ? localInfo.getWidth() : localInfo.getHeight(); if (localWidth != photo.getWidth() || localHeight != photo.getHeight()) { log.info(String.format( "Image dimensions are different: (local %dx%d vs remote %dx%d). Local file will be updated.", localInfo.getWidth(), localInfo.getHeight(), photo.getWidth(), photo.getHeight())); return true; } } else { log.warn("Local file was not image! Renaming before overwrite. (" + localPath.getName() + ")"); File renamed = new File(localPath + ".old"); if (!localPath.renameTo(renamed)) log.warn("Unable to rename file"); updateLocal = true; } } else { log.debug("No local file existed: " + localPath); // Nothing here, so always write updateLocal = true; } return updateLocal; } // Todo - optimise the number of exists() calls to reduce I/O public String getName() { if (remotePhoto != null) return remotePhoto.getTitle().getPlainText(); if (localFile.exists()) return localFile.getName(); throw new IllegalArgumentException("No local or remote file. What?"); } }