WatcherNIO2.java

/*
 * Copyright 2016 the original author or authors.
 *
 * This file is part of HotswapAgent.
 *
 * HotswapAgent is free software: you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the
 * Free Software Foundation, either version 2 of the License, or (at your
 * option) any later version.
 *
 * HotswapAgent is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
 * Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with HotswapAgent. If not, see http://www.gnu.org/licenses/.
 */
package org.hotswap.agent.watch.nio;

import java.io.IOException;
import java.nio.file.FileVisitResult;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.SimpleFileVisitor;
import java.nio.file.WatchEvent;
import java.nio.file.WatchKey;
import java.nio.file.attribute.BasicFileAttributes;

/**
 * NIO2 watcher implementation.
 * <p/>
 * Java 7 (NIO2) watch a directory (or tree) for changes to files.
 * <p/>
 * By http://docs.oracle.com/javase/tutorial/essential/io/examples/WatchDir.java
 *
 * @author Jiri Bubnik
 * @author alpapad@gmail.com
 */
public class WatcherNIO2 extends AbstractNIO2Watcher {
    private final static WatchEvent.Modifier HIGH;

    static {
        HIGH =  getWatchEventModifier("com.sun.nio.file.SensitivityWatchEventModifier","HIGH");
    }

    public WatcherNIO2() throws IOException {
        super();
    }


    /**
     * Register the given directory, and all its sub-directories, with the
     * WatchService.
     */
    @Override
    protected void registerAll(final Path parent, Path start) throws IOException {
        // register directory and sub-directories
        if (parent != null) {
            LOGGER.debug("Registering directory  {} under parent {}", start, parent);
        } else {
            LOGGER.debug("Registering directory  {}", start);
        }

        Files.walkFileTree(start, new SimpleFileVisitor<Path>() {
            @Override
            public FileVisitResult preVisitDirectory(Path dir, BasicFileAttributes attrs) throws IOException {
                register(dir);
                return FileVisitResult.CONTINUE;
            }
        });
    }

    /**
     * Register the given directory with the WatchService
     */
    private void register(Path dir) throws IOException {
        // try to set high sensitivity
        final WatchKey key = HIGH == null ? dir.register(watcher, KINDS) : dir.register(watcher, KINDS, HIGH);

        keys.put(key, PathPair.get(dir));
    }
}