// The actual scan logic. Switches state to RUNNING, // and scan the list of given dirs. // The list is a live object which is updated by this method. // This would allow us to implement methods like "pause" and "resume", // since all the info needed to resume would be in the list. // private void scan(ScanTask task, LinkedList<File> list) { setStateAndNotify(RUNNING); task.info = "In Progress"; try { // The FileFilter will tell us which files match and which don't. // final FileFilter filter = config.buildFileFilter(); // We have two condition to end the loop: either the list is // empty, meaning there's nothing more to scan, or the state of // the DirectoryScanner was asynchronously switched to STOPPED by // another thread, e.g. because someone called "stop" on the // ScanManagerMXBean // while (!list.isEmpty() && state == RUNNING) { // Get and remove the first element in the list. // final File current = list.poll(); // Increment number of file scanned. task.scanned++; // If 'current' is a file, it's already been matched by our // file filter (see below): act on it. // Note that for the first iteration of this loop, there will // be one single file in the list: the root directory for this // scanner. // if (current.isFile()) { task.matching++; actOn(current); } // If 'current' is a directory, then // find files and directories that match the file filter // in this directory // if (current.isDirectory()) { // Gets matching files and directories final File[] content = current.listFiles(filter); if (content == null) continue; // Adds all matching file to the list. list.addAll(0, Arrays.asList(content)); } } // The loop terminated. If the list is empty, then we have // completed our task. If not, then somebody must have called // stop() on this directory scanner. // if (list.isEmpty()) { task.info = "Successfully Completed"; setStateAndNotify(COMPLETED); } } catch (Exception x) { // We got an exception: stop the scan // task.info = "Failed: " + x; if (LOG.isLoggable(Level.FINEST)) LOG.log(Level.FINEST, "scan task failed: " + x, x); else if (LOG.isLoggable(Level.FINE)) LOG.log(Level.FINE, "scan task failed: " + x); setStateAndNotify(STOPPED); } catch (Error e) { // We got an Error: // Should not happen unless we ran out of memory or // whatever - don't even try to notify, but // stop the scan anyway! // state = STOPPED; task.info = "Error: " + e; // rethrow error. // throw e; } }