+/*******************************************************************************\r
+ * Copyright (c) 2010- Association for Decentralized Information Management in\r
+ * Industry THTH ry.\r
+ * All rights reserved. This program and the accompanying materials\r
+ * are made available under the terms of the Eclipse Public License v1.0\r
+ * which accompanies this distribution, and is available at\r
+ * http://www.eclipse.org/legal/epl-v10.html\r
+ * \r
+ * Contributors:\r
+ * VTT Technical Research Centre of Finland - initial API and implementation\r
+ *******************************************************************************/\r
+package org.simantics.databoard.accessor.impl;\r
+\r
+import java.io.File;\r
+import java.io.FileFilter;\r
+import java.util.ArrayList;\r
+import java.util.HashSet;\r
+import java.util.List;\r
+import java.util.Set;\r
+import java.util.Timer;\r
+import java.util.TimerTask;\r
+import java.util.concurrent.CopyOnWriteArrayList;\r
+\r
+/**\r
+ * DirectoryWatch monitors a directory for file additions / removals.\r
+ * <p>\r
+ * DirectoryWatch is used in the long wait for WatchService. \r
+ *\r
+ * @author Toni Kalajainen <toni.kalajainen@vtt.fi>\r
+ */\r
+public class DirectoryWatch {\r
+\r
+ public static final long POLL_INTERVAL = 10000; // seconds\r
+ \r
+ Timer timer;\r
+ FileFilter filter;\r
+ File directory;\r
+ List<File> knownFiles;\r
+ CopyOnWriteArrayList<DirectoryListener> listeners = new CopyOnWriteArrayList<DirectoryListener>();\r
+\r
+ TimerTask task = new TimerTask() { \r
+ public void run() {\r
+ poll();\r
+ } \r
+ };\r
+ \r
+ public DirectoryWatch(File directory, FileFilter filter) {\r
+ this.directory = directory;\r
+ this.filter = filter;\r
+ knownFiles = readFiles();\r
+ timer = new Timer(directory.toString()+" watcher", true);\r
+ timer.schedule(task, 1, POLL_INTERVAL);\r
+ }\r
+ \r
+ /**\r
+ * Close the timer. \r
+ * This method does one last poll.\r
+ */\r
+ public void close() { \r
+ timer.cancel();\r
+ poll();\r
+ }\r
+ \r
+ public static class DirectoryEvent {\r
+ public Set<File> filesAdded = new HashSet<File>();\r
+ public Set<File> filesRemoved = new HashSet<File>();\r
+ }\r
+ \r
+ public interface DirectoryListener {\r
+ void onWatchEvent(DirectoryEvent e);\r
+ }\r
+ \r
+ public void addListener(DirectoryListener listener) {\r
+ listeners.add(listener); \r
+ }\r
+ \r
+ public void removeListener(DirectoryListener listener) { \r
+ listeners.remove(listener);\r
+ }\r
+ \r
+ /**\r
+ * Get a snapshot of currently known files\r
+ * \r
+ * @return a snapshot of files\r
+ */\r
+ public List<File> files() {\r
+ return knownFiles;\r
+ }\r
+ \r
+ /**\r
+ * Reload the directory\r
+ */\r
+ public void refresh() {\r
+ poll();\r
+ }\r
+ \r
+ /**\r
+ * Add file to the known list without reading the disk. \r
+ * The modification is void after next timer refresh. \r
+ * \r
+ * @param f\r
+ */\r
+ public synchronized void add(File f) {\r
+ ArrayList<File> newList = new ArrayList<File>( knownFiles );\r
+ newList.add(f);\r
+ knownFiles = newList;\r
+ }\r
+ \r
+ /**\r
+ * Remove file from the known list without reading the disk.\r
+ * The modification is void after next timer refresh. \r
+ * \r
+ * @param f\r
+ */\r
+ public synchronized void remove(File f) {\r
+ ArrayList<File> newList = new ArrayList<File>( knownFiles );\r
+ newList.remove(f);\r
+ knownFiles = newList; \r
+ }\r
+ \r
+ /**\r
+ * Read files\r
+ * @return a list of absolute files\r
+ */\r
+ private List<File> readFiles() { \r
+ File[] files = directory.listFiles(filter);\r
+ List<File> newFiles = new ArrayList<File>( files.length );\r
+ for (File f : files) {\r
+// System.out.println(f);\r
+// f = f.getAbsoluteFile();\r
+// System.out.println(f);\r
+ newFiles.add(f); \r
+ }\r
+ return newFiles;\r
+ }\r
+ \r
+ /**\r
+ * Read files and spawn events\r
+ */\r
+ private synchronized void poll() {\r
+ DirectoryEvent e = read();\r
+ if (e.filesAdded.isEmpty() && e.filesRemoved.isEmpty()) return;\r
+ // Spawn an event\r
+ for (DirectoryListener l : listeners)\r
+ l.onWatchEvent(e);\r
+ }\r
+ \r
+ private DirectoryEvent read() {\r
+ List<File> oldFiles = knownFiles;\r
+ List<File> newFiles = readFiles();\r
+ knownFiles = newFiles;\r
+\r
+ DirectoryEvent result = new DirectoryEvent();\r
+ result.filesAdded.addAll(newFiles);\r
+ result.filesAdded.removeAll(oldFiles);\r
+\r
+ result.filesRemoved.addAll(oldFiles);\r
+ result.filesRemoved.removeAll(newFiles);\r
+ \r
+ return result;\r
+ }\r
+ \r
+}\r
+\r