--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/jdk/src/share/sample/nio/file/WatchDir.java Sun Feb 15 12:25:54 2009 +0000
@@ -0,0 +1,196 @@
+/*
+ * Copyright 2008-2009 Sun Microsystems, Inc. All Rights Reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * - Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *
+ * - Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ *
+ * - Neither the name of Sun Microsystems nor the names of its
+ * contributors may be used to endorse or promote products derived
+ * from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
+ * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
+ * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+ * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
+ * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+ * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+import java.nio.file.*;
+import static java.nio.file.StandardWatchEventKind.*;
+import static java.nio.file.LinkOption.*;
+import java.nio.file.attribute.*;
+import java.io.*;
+import java.util.*;
+
+/**
+ * Example to watch a directory (or tree) for changes to files.
+ */
+
+public class WatchDir {
+
+ private final WatchService watcher;
+ private final Map<WatchKey,Path> keys;
+ private final boolean recursive;
+ private boolean trace = false;
+
+ @SuppressWarnings("unchecked")
+ static <T> WatchEvent<T> cast(WatchEvent<?> event) {
+ return (WatchEvent<T>)event;
+ }
+
+ /**
+ * Register the given directory with the WatchService
+ */
+ private void register(Path dir) throws IOException {
+ WatchKey key = dir.register(watcher, ENTRY_CREATE, ENTRY_DELETE, ENTRY_MODIFY);
+ if (trace) {
+ FileRef prev = keys.get(key);
+ if (prev == null) {
+ System.out.format("register: %s\n", dir);
+ } else {
+ if (!dir.equals(prev)) {
+ System.out.format("update: %s -> %s\n", prev, dir);
+ }
+ }
+ }
+ keys.put(key, dir);
+ }
+
+ /**
+ * Register the given directory, and all its sub-directories, with the
+ * WatchService.
+ */
+ private void registerAll(final Path start) throws IOException {
+ // register directory and sub-directories
+ Files.walkFileTree(start, new SimpleFileVisitor<Path>() {
+ @Override
+ public FileVisitResult preVisitDirectory(Path dir) {
+ try {
+ register(dir);
+ } catch (IOException x) {
+ throw new IOError(x);
+ }
+ return FileVisitResult.CONTINUE;
+ }
+ });
+ }
+
+ /**
+ * Creates a WatchService and registers the given directory
+ */
+ WatchDir(Path dir, boolean recursive) throws IOException {
+ this.watcher = FileSystems.getDefault().newWatchService();
+ this.keys = new HashMap<WatchKey,Path>();
+ this.recursive = recursive;
+
+ if (recursive) {
+ System.out.format("Scanning %s ...\n", dir);
+ registerAll(dir);
+ System.out.println("Done.");
+ } else {
+ register(dir);
+ }
+
+ // enable trace after initial registration
+ this.trace = true;
+ }
+
+ /**
+ * Process all events for keys queued to the watcher
+ */
+ void processEvents() {
+ for (;;) {
+
+ // wait for key to be signalled
+ WatchKey key;
+ try {
+ key = watcher.take();
+ } catch (InterruptedException x) {
+ return;
+ }
+
+ Path dir = keys.get(key);
+ if (dir == null) {
+ System.err.println("WatchKey not recognized!!");
+ continue;
+ }
+
+ for (WatchEvent<?> event: key.pollEvents()) {
+ WatchEvent.Kind kind = event.kind();
+
+ // TBD - provide example of how OVERFLOW event is handled
+ if (kind == OVERFLOW) {
+ continue;
+ }
+
+ // Context for directory entry event is the file name of entry
+ WatchEvent<Path> ev = cast(event);
+ Path name = ev.context();
+ Path child = dir.resolve(name);
+
+ // print out event
+ System.out.format("%s: %s\n", event.kind().name(), child);
+
+ // if directory is created, and watching recursively, then
+ // register it and its sub-directories
+ if (recursive && (kind == ENTRY_CREATE)) {
+ try {
+ if (Attributes.readBasicFileAttributes(child, NOFOLLOW_LINKS).isDirectory()) {
+ registerAll(child);
+ }
+ } catch (IOException x) {
+ // ignore to keep sample readbale
+ }
+ }
+ }
+
+ // reset key and remove from set if directory no longer accessible
+ boolean valid = key.reset();
+ if (!valid) {
+ keys.remove(key);
+
+ // all directories are inaccessible
+ if (keys.isEmpty()) {
+ break;
+ }
+ }
+ }
+ }
+
+ static void usage() {
+ System.err.println("usage: java WatchDir [-r] dir");
+ System.exit(-1);
+ }
+
+ public static void main(String[] args) throws IOException {
+ // parse arguments
+ if (args.length == 0 || args.length > 2)
+ usage();
+ boolean recursive = false;
+ int dirArg = 0;
+ if (args[0].equals("-r")) {
+ if (args.length < 2)
+ usage();
+ recursive = true;
+ dirArg++;
+ }
+
+ // register directory and process its events
+ Path dir = Paths.get(args[dirArg]);
+ new WatchDir(dir, recursive).processEvents();
+ }
+}