package br.com.ingenieux.mojo.jbake.util;
import org.apache.commons.io.monitor.FileAlterationListenerAdaptor;
import org.apache.commons.io.monitor.FileAlterationMonitor;
import org.apache.commons.io.monitor.FileAlterationObserver;
import java.io.File;
import java.io.IOException;
import java.util.concurrent.ArrayBlockingQueue;
import java.util.concurrent.BlockingQueue;
import java.util.concurrent.TimeUnit;
/**
* Example to watch a directory (or tree) for changes to files.
*/
public class DirWatcher {
private final FileAlterationObserver observer;
private final FileAlterationMonitor monitor;
private final BlockingQueue<Long> changeQueue = new ArrayBlockingQueue<Long>(1);
/**
* Creates a WatchService and registers the given directory
*/
public DirWatcher(File dir) throws IOException {
this.observer = new FileAlterationObserver(dir);
this.monitor = new FileAlterationMonitor(1000, observer);
observer.addListener(new FileAlterationListenerAdaptor() {
@Override
public void onFileCreate(File file) {
onUpdated();
}
@Override
public void onFileChange(File file) {
onUpdated();
}
});
}
public void start() throws Exception {
monitor.start();
}
public void stop() {
try {
monitor.stop();
} catch (Exception exc) {
}
}
private void onUpdated() {
changeQueue.add(Long.valueOf(System.currentTimeMillis()));
}
/**
* Process all events for keys queued to the watcher
*/
public Long processEvents() throws InterruptedException {
return changeQueue.poll(1, TimeUnit.SECONDS);
}
}