package com.wilutions.jsfs;
/*
* Copyright (c) 2008, 2010, Oracle and/or its affiliates. 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 Oracle 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 static java.nio.file.LinkOption.NOFOLLOW_LINKS;
import static java.nio.file.StandardWatchEventKinds.ENTRY_CREATE;
import static java.nio.file.StandardWatchEventKinds.ENTRY_DELETE;
import static java.nio.file.StandardWatchEventKinds.ENTRY_MODIFY;
import static java.nio.file.StandardWatchEventKinds.OVERFLOW;
import java.io.IOException;
import java.nio.file.FileSystems;
import java.nio.file.FileVisitResult;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.SimpleFileVisitor;
import java.nio.file.WatchEvent;
import java.nio.file.WatchEvent.Kind;
import java.nio.file.WatchKey;
import java.nio.file.WatchService;
import java.nio.file.attribute.BasicFileAttributes;
import java.util.HashMap;
import java.util.Map;
import byps.RemoteException;
/**
* Directory watcher.
* Most of the code is copied from the example code provided by ORACLE.
*/
public class WatchDir extends Thread {
private final WatchService watcher;
private final Map<WatchKey, Path> keys;
private final boolean recursive;
private boolean trace = false;
private final int watchHandle;
private final FileSystemNotify notifyService;
private final String extraInfo;
@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) {
Path 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, BasicFileAttributes attrs) throws IOException {
register(dir);
return FileVisitResult.CONTINUE;
}
});
}
/**
* Creates a WatchService and registers the given directory
* @param watchHandle
*/
public WatchDir(FileSystemNotify notifyService, int watchHandle, String extraInfo, Path dir, boolean recursive) throws IOException {
this.notifyService = notifyService;
this.watchHandle = watchHandle;
this.extraInfo = extraInfo;
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;
}
@Override
public void run() {
try {
processEvents();
}
catch (Throwable e) {
}
}
/**
* Process all events for keys queued to the watcher
*/
private 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()) {
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);
{
notifyFileChange(kind, child);
}
// if directory is created, and watching recursively, then
// register it and its sub-directories
if (recursive && (kind == ENTRY_CREATE)) {
try {
if (Files.isDirectory(child, NOFOLLOW_LINKS)) {
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;
}
}
}
}
private void notifyFileChange(Kind<?> kind, Path child) {
WatchFolderNotifyInfo notifyInfo = new WatchFolderNotifyInfo();
notifyInfo.setId(watchHandle);
notifyInfo.setExtraInfo(extraInfo);
if (kind == ENTRY_CREATE) {
notifyInfo.setKind(EWatchFolderNotifyKind.EntryCreated);
}
else if (kind == ENTRY_MODIFY) {
notifyInfo.setKind(EWatchFolderNotifyKind.EntryModified);
}
else if (kind == ENTRY_DELETE) {
notifyInfo.setKind(EWatchFolderNotifyKind.EntryDeleted);
}
FileInfo fileInfo = FileInfoHelper.makeFileInfo(child.toFile());
notifyInfo.setFileInfo(fileInfo);
try {
notifyService.notify(notifyInfo);
} catch (RemoteException e) {
e.printStackTrace();
}
}
public void done() {
try {
watcher.close();
}
catch (IOException ignored) {}
}
// 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();
// }
}