Migrated source code from Simantics SVN

[simantics/platform.git] / bundles / org.simantics.databoard / src / org / simantics / databoard / accessor / impl / DirectoryWatch.java

diff --git a/bundles/org.simantics.databoard/src/org/simantics/databoard/accessor/impl/DirectoryWatch.java b/bundles/org.simantics.databoard/src/org/simantics/databoard/accessor/impl/DirectoryWatch.java
new file mode 100644 (file)
index 0000000..1e83fd4
--- /dev/null
+++ b/bundles/org.simantics.databoard/src/org/simantics/databoard/accessor/impl/DirectoryWatch.java
@@ -0,0 +1,164 @@
+/*******************************************************************************\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