fix: exception when watcher services are closed

When watcher are closed and there is still a running thread waiting for some event,
an java.nio.file.ClosedWatchServiceException is thrown. According to the
javadoc (https://docs.oracle.com/javase/7/docs/api/java/nio/file/WatchService.html#take%28%29)
this is the expected behavior, so we don't need to propagate this exception outside the thread.

restx-common/src/main/java/restx/common/watch/StdWatcherService.java

@@ -111,60 +111,65 @@ public FileVisitResult preVisitDirectory(Path dir, BasicFileAttributes attrs)
         * 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();

                    // Context for directory entry event is the file name of entry
                    WatchEvent<Path> ev = cast(event);

                    coalescor.post(FileWatchEvent.newInstance(root, dir, ev.context(), ev.kind(), ev.count()));

                    if (kind == OVERFLOW) {
                        continue;
                    }

                    Path name = ev.context();
                    Path child = dir.resolve(name);

                    // 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;
                    }
                }
            try {
                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();

						// Context for directory entry event is the file name of entry
						WatchEvent<Path> ev = cast(event);

						coalescor.post(FileWatchEvent.newInstance(root, dir, ev.context(), ev.kind(), ev.count()));

						if (kind == OVERFLOW) {
							continue;
						}

						Path name = ev.context();
						Path child = dir.resolve(name);

						// 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;
						}
					}
				}
            } catch (ClosedWatchServiceException e) {
                // just ignore this exception, it just meant that the service has been closed,
                // while the current thread was waiting some event with the "take" method.
            }
        }