net.codestory.http.reload.NativeWatchService Maven / Gradle / Ivy

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/**
 * Copyright (C) 2013-2014 [email protected]
 *
 * Licensed 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
 */
package net.codestory.http.reload;

import static com.sun.nio.file.SensitivityWatchEventModifier.HIGH;
import static java.nio.file.Files.walkFileTree;
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 static net.codestory.http.io.FileVisitor.onDirectory;

import java.io.IOException;
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 NativeWatchService implements WatchServiceFacade {
  private final WatchService watcher;
  private final AtomicBoolean run;

  public NativeWatchService(Path folder) {
    this.run = new AtomicBoolean(false);

    try {
      watcher = folder.getFileSystem().newWatchService();

      walkFileTree(folder, onDirectory(dir -> dir.register(watcher, new WatchEvent.Kind[]{ENTRY_CREATE, ENTRY_MODIFY, ENTRY_DELETE}, HIGH)));
    } catch (IOException e) {
      throw new IllegalStateException("Unable to watch folder " + folder, e);
    }
  }

  @Override
  public void stop() {
    run.set(false);
  }

  @Override
  public void onChange(FolderChangeListener listener) {
    new Thread(() -> {
      run.set(true);

      while (run.get()) {
        try {
          WatchKey take = watcher.take();

          boolean changed = false;
          for (WatchEvent event : take.pollEvents()) {
            if (event.kind() == OVERFLOW) {
              continue;
            }

            // consume all events of this shitty API
            changed = true;
          }

          if (changed) {
            listener.onChange();
          }

          take.reset();
        } catch (InterruptedException e) {
          // Ignore
        }
      }
    }).start();
  }
}