Created
September 25, 2011 22:45
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Uses the Java 7 WatchEvent filesystem API from within Scala
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| /** | |
| * watcher.scala | |
| * | |
| * Uses the Java 7 WatchEvent filesystem API from within Scala. | |
| * Based on http://markusjais.com/file-system-events-with-java-7/ | |
| * | |
| * @author Chris Eberle <eberle1080@gmail.com> | |
| * @version 0.1 | |
| */ | |
| import scala.collection.JavaConverters._ | |
| import util.control.Breaks._ | |
| import java.io.IOException | |
| import java.nio.file.Path | |
| import java.nio.file.StandardWatchEventKinds | |
| import java.nio.file.WatchEvent | |
| import java.nio.file.WatchKey | |
| import java.nio.file.WatchService | |
| import java.nio.file.FileSystems | |
| class DirectoryWatcher(val path:Path) extends Runnable { | |
| def printEvent(event:WatchEvent[_]) : Unit = { | |
| val kind = event.kind | |
| val event_path = event.context().asInstanceOf[Path] | |
| if(kind.equals(StandardWatchEventKinds.ENTRY_CREATE)) { | |
| println("Entry created: " + event_path) | |
| } | |
| else if(kind.equals(StandardWatchEventKinds.ENTRY_DELETE)) { | |
| println("Entry deleted: " + event_path) | |
| } | |
| else if(kind.equals(StandardWatchEventKinds.ENTRY_MODIFY)) { | |
| println("Entry modified: " + event_path) | |
| } | |
| } | |
| override def run(): Unit = { | |
| try { | |
| val watchService = path.getFileSystem().newWatchService() | |
| path.register(watchService, StandardWatchEventKinds.ENTRY_CREATE, | |
| StandardWatchEventKinds.ENTRY_MODIFY, | |
| StandardWatchEventKinds.ENTRY_DELETE) | |
| breakable { | |
| while (true) { | |
| val watchKey = watchService.take() | |
| watchKey.pollEvents().asScala.foreach( e => { | |
| printEvent(e) | |
| }) | |
| if (!watchKey.reset()) { | |
| println("No longer valid") | |
| watchKey.cancel() | |
| watchService.close() | |
| break | |
| } | |
| } | |
| } | |
| } catch { | |
| case ie: InterruptedException => println("InterruptedException: " + ie) | |
| case ioe: IOException => println("IOException: " + ioe) | |
| case e: Exception => println("Exception: " + e) | |
| } | |
| } | |
| } | |
| println("Starting watch service...") | |
| val path = FileSystems.getDefault().getPath("/home/chris/scala/watch") | |
| val dir_watcher = new DirectoryWatcher(path) | |
| val watch_thread = new Thread(dir_watcher) | |
| watch_thread.start() |
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