com.nitorcreations.willow.utils.PollingFile Maven / Gradle / Ivy
package com.nitorcreations.willow.utils;
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 static java.nio.file.StandardWatchEventKinds.OVERFLOW;
import java.io.File;
import java.io.IOException;
import java.net.URI;
import java.nio.file.FileSystems;
import java.nio.file.Path;
import java.nio.file.WatchEvent;
import java.nio.file.WatchKey;
import java.nio.file.WatchService;
import java.util.concurrent.atomic.AtomicBoolean;
public class PollingFile extends File implements Runnable {
private static final long serialVersionUID = -6683198740670677087L;
private final AtomicBoolean running = new AtomicBoolean(true);
private transient Thread poller = null;
private transient FileListener listener;
public interface FileListener {
void fileChanged(File file, WatchEvent.Kind kind);
}
public PollingFile(File parent, String child, FileListener listener) {
super(parent, child);
this.listener = listener;
}
public PollingFile(String name, FileListener listener) {
super(name);
this.listener = listener;
}
public PollingFile(String parent, String child, FileListener listener) {
super(parent, child);
this.listener = listener;
}
public PollingFile(URI uri, FileListener listener) {
super(uri);
this.listener = listener;
}
public void startListening() {
poller = new Thread(this, getAbsolutePath() + "-listener");
poller.start();
}
@Override
public void run() {
try {
WatchService watcher = FileSystems.getDefault().newWatchService();
getAbsoluteFile().getParentFile().toPath().register(watcher, ENTRY_MODIFY, ENTRY_CREATE, ENTRY_DELETE);
while (running.get()) {
WatchKey key = null;
try {
key = watcher.take();
} catch (InterruptedException x) {
return;
}
for (WatchEvent event: key.pollEvents()) {
WatchEvent.Kind kind = event.kind();
if (kind == OVERFLOW) {
continue;
}
@SuppressWarnings("unchecked")
WatchEvent ev = (WatchEvent)event;
Path context = ev.context();
if (context.equals(toPath())) {
listener.fileChanged(this, ev.kind());
}
}
boolean valid = key.reset();
if (!valid) {
break;
}
}
} catch (IOException e) {
throw new RuntimeException("Failed to watch file changes", e);
}
}
public void stop() {
running.set(false);
if (poller != null) {
poller.interrupt();
}
}
@Override
@SuppressWarnings("PMD.UselessOverridingMethod")
public int hashCode() {
return super.hashCode();
}
@Override
public boolean equals(Object obj) {
if (obj != null && obj.getClass().isAssignableFrom(PollingFile.class)) {
return compareTo((File)obj) == 0;
}
return false;
}
}