Apache VFS file listener PoC Quickstart

SimpleFileMonitor.java

/**
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements. See the NOTICE file distributed with this
 * work for additional information regarding copyright ownership. The ASF
 * licenses this file to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * 
 * http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 * License for the specific language governing permissions and limitations under
 * the License.
 */

import java.io.File;
import java.io.IOException;

import org.apache.commons.vfs2.FileChangeEvent;
import org.apache.commons.vfs2.FileListener;
import org.apache.commons.vfs2.FileObject;
import org.apache.commons.vfs2.FileSystemManager;
import org.apache.commons.vfs2.VFS;
import org.apache.commons.vfs2.impl.DefaultFileMonitor;

/**
 * Apache VFS file listener PoC Quickstart
 * 
 * Dependencies: org.apache.commons:commons-vfs2:2.0
 * 
 * @author Arun Babu Neelicattu (abn)
 * 
 */

public class SimpleFileMonitor {

    private static void monitor(File file) throws IOException {
        // source: http://stackoverflow.com/a/7977428/1874604
        // setup monitoring
        FileSystemManager manager = VFS.getManager();
        FileObject fobj = manager.resolveFile(file.getPath());
        DefaultFileMonitor fm = new DefaultFileMonitor(new SimpleFileListener());
        fm.setDelay(500);
        fm.addFile(fobj);
        fm.start();
    }

    public static void main(String[] args) throws IOException {
        File file = File.createTempFile("simplefile", ".tmp");
        monitor(file);
        file.delete();
    }

    private static class SimpleFileListener implements FileListener {

        public void fileChanged(FileChangeEvent arg0) throws Exception {
            System.out.println("File changed");

        }

        public void fileCreated(FileChangeEvent arg0) throws Exception {
            System.out.println("File created");
        }

        public void fileDeleted(FileChangeEvent arg0) throws Exception {
            System.out.println("File deleted");
        }
    }
}