Hello,
I have a question posted in
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I have a Vaadin web application, that is deploying OK. BUT when I add a FolderWatcher service as a Listener using @WebListenerThe application fails to deploy, but it starts the thread if I disable the annotation @WebListener the application does deploy.
Here is a ContextListener class
[code]
import java.io.IOException;
import java.nio.file.Path;
import java.nio.file.Paths;
import javax.servlet.ServletContextEvent;
import javax.servlet.ServletContextListener;
import javax.servlet.annotation.WebListener;
import com.vaadin.demo.dashboard.util.FolderWatchService;
import com.vaadin.demo.dashboard.util.PropertiesCache;
@WebListener
public class ContextListener implements ServletContextListener {
@Override
public void contextDestroyed(ServletContextEvent arg0) {
System.out.println("#### Folder watcher service destroyed");
}
@Override
public void contextInitialized(ServletContextEvent arg0) {
System.out.println("#### Folder watcher service initialized");
Path dir = Paths.get(PropertiesCache.getInstance().getProperty("file_input_location"));
try {
new FolderWatchService(dir).processEvents();
System.out.println("#### Folder watcher service started");
} catch (IOException e) {
System.out.println("#### Folder watcher Problem");
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
[/code]Folder watcher class
[code]
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 java.io.File;
import java.io.FileNotFoundException;
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.WatchKey;
import java.nio.file.WatchService;
import java.nio.file.attribute.BasicFileAttributes;
import java.util.Date;
import java.util.HashMap;
import java.util.Map;
import java.util.Scanner;
import java.util.logging.Level;
import java.util.logging.Logger;
import org.apache.commons.io.FilenameUtils;
import com.vaadin.demo.dashboard.data.Kod_SubsDataControl;
import com.vaadin.demo.dashboard.domain.Kod_subs;
public class FolderWatchService {
private final WatchService watcher;
private final Map<WatchKey, Path> keys;
private static final Logger LOGGER = Logger.getLogger( FolderWatchService.class.getName() );
/**
* Creates a WatchService and registers the given directory
*/
public FolderWatchService(Path dir) throws IOException {
this.watcher = FileSystems.getDefault().newWatchService();
this.keys = new HashMap<WatchKey, Path>();
walkAndRegisterDirectories(dir);
}
/**
* Register the given directory with the WatchService; This function will be called by FileVisitor
*/
private void registerDirectory(Path dir) throws IOException
{
WatchKey key = dir.register(watcher, ENTRY_CREATE, ENTRY_DELETE, ENTRY_MODIFY);
keys.put(key, dir);
}
/**
* Register the given directory, and all its sub-directories, with the WatchService.
*/
private void walkAndRegisterDirectories(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 {
registerDirectory(dir);
return FileVisitResult.CONTINUE;
}
});
}
/**
* Process all events for keys queued to the watcher
*/
public 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) {
LOGGER.log( Level.FINE, "WatchKey not recognized!!", "" );
System.err.println("WatchKey not recognized!!");
continue;
}
for (WatchEvent<?> event : key.pollEvents()) {
@SuppressWarnings("rawtypes")
WatchEvent.Kind kind = event.kind();
// Context for directory entry event is the file name of entry
@SuppressWarnings("unchecked")
Path name = ((WatchEvent<Path>)event).context();
Path child = dir.resolve(name);
// print out event
// System.out.format(“%s: %s\n”, event.kind().name(), child);
// System.out.println("New path created: " + child);
String fileContent;
// if directory is created, and watching recursively, then register it and its sub-directories
if (kind == ENTRY_CREATE) {
System.out.println("File created");
LOGGER.log( Level.FINER, "New File created", "" );
readFile(child.toString());
}
}
// 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 static void readFile(String pathname){
try {
File file = new File(pathname);
// System.out.println("FilePath: "+pathname);
// System.out.println("Absolute File: "+file.getAbsolutePath());
StringBuilder fileContents = new StringBuilder((int)file.length());
Scanner scanner = new Scanner(file);
String lineSeparator = System.getProperty(“line.separator”);
try {
while(scanner.hasNextLine()) {
fileContents.append(scanner.nextLine() + lineSeparator);
}
String fileContent = fileContents.toString();
System.out.println("File name: "+FilenameUtils.getBaseName(pathname));
LOGGER.log( Level.FINER, "File name: "+FilenameUtils.getBaseName(pathname), "" );
String title = "File Title: "+fileContent.substring(0, 64).trim().lastIndexOf(System.getProperty("line.separator"))+"...";
} finally {
scanner.close();
}
} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
[/code]What am I doing wrong?