Vfrdtyky

I have a folder that must contain always one file config8, and if a new file is created in this folder the old file is deleted and replaced by the new file with the same name config8.

I write this code

       File file1 = new File("/home/olfa/Bureau/config/config8");

       File file2 = new File("/home/olfa/Bureau/config/config9");

      while (file2.exists())

      {

          file1.delete();

          file2.renameTo(file1); }

      }

    serverConnection = new ServerConnection("/home/olfa/Bureau/config/config8");

I need to add a loop to check everytime if config9 is created.

Instead of a loop try a WatchService.

Basically you would be watching a particular directory for change and then you can react on this change.

https://docs.oracle.com/javase/tutorial/essential/io/notification.html

For example :

import static java.nio.file.StandardWatchEventKinds.*;



WatchService watcher = FileSystems.getDefault().newWatchService();



Path dir = ...;

try {

    WatchKey key = dir.register(watcher,

                       ENTRY_CREATE,

                       ENTRY_DELETE,

                       ENTRY_MODIFY);

} catch (IOException x) {

System.err.println(x);

}

Then you can process your key events.

If you have to solve this task with Java 1.6, you can use https://commons.apache.org/proper/commons-vfs/, version 2.1.

Here is an example for moving all incoming config files to "config8":

import org.apache.commons.vfs2.*;

import org.apache.commons.vfs2.impl.DefaultFileMonitor;



import java.io.File;



public class ConfigWatcher {

    private static final String configDirName = "target/config";

    private static final String configName = "config8";

    private static final String absoluteConfigName = new File(configDirName + File.separator + configName).getAbsolutePath();

    private FileSystemManager manager = null;

    FileObject configDir = null;

    private FileObject configFile = null;

    private FileChangeEvent lastEvent = null;



    public void watchConfig() throws Exception {

        manager = VFS.getManager();



        DefaultFileMonitor fm = new DefaultFileMonitor(new ConfigFileListener());

        configFile = manager.resolveFile(absoluteConfigName);

        configDir = manager.resolveFile(new File(configDirName).getAbsolutePath());

        fm.setDelay(1000);

        fm.addFile(configDir);

        fm.start();

    }



    class ConfigFileListener implements FileListener {

        public void fileCreated(FileChangeEvent fileChangeEvent) throws Exception {

            FileObject latestConfigFile = fileChangeEvent.getFile();

            String fileBaseName = fileChangeEvent.getFile().getName().getBaseName();

            if (!configName.endsWith(fileBaseName) && !fileChangeEvent.equals(lastEvent)) {

                System.out.println("new config detected - move config");

                latestConfigFile.moveTo(configFile);

            }

            lastEvent = fileChangeEvent;

        }



        public void fileChanged(FileChangeEvent fileChangeEvent) {

        }



        public void fileDeleted(FileChangeEvent fileChangeEvent) {

        }

    }





    public static void main(String args) throws Exception {

        final ConfigWatcher configWatcher = new ConfigWatcher();

        configWatcher.watchConfig();

        while (true) {

            Thread.sleep(1000);

        }

    }

}