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/* @test
 * @bug 4313887
 * @summary Sanity test for JDK-specific sensitivity level watch event modifier
 * @modules jdk.unsupported
 * @library ..
 * @run main/timeout=240 SensitivityModifier
 * @key randomness
 */

import java.nio.file.*;
import static java.nio.file.StandardWatchEventKinds.*;
import java.io.OutputStream;
import java.io.IOException;
import java.util.Random;
import java.util.concurrent.TimeUnit;
import com.sun.nio.file.SensitivityWatchEventModifier;

public class SensitivityModifier {

    static final Random rand = new Random();

    static void register(Path[] dirs, WatchService watcher) throws IOException {
        SensitivityWatchEventModifier[] sensitivtives =
            SensitivityWatchEventModifier.values();
        for (int i=0; i<dirs.length; i++) {
            SensitivityWatchEventModifier sensivity =
                sensitivtives[ rand.nextInt(sensitivtives.length) ];
            Path dir = dirs[i];
            dir.register(watcher, new WatchEvent.Kind<?>[]{ ENTRY_MODIFY }, sensivity);
        }
    }

    @SuppressWarnings("unchecked")
    static void doTest(Path top) throws Exception {
        FileSystem fs = top.getFileSystem();
        try (WatchService watcher = fs.newWatchService()) {

            // create directories and files
            int nDirs = 5 + rand.nextInt(20);
            int nFiles = 50 + rand.nextInt(50);
            Path[] dirs = new Path[nDirs];
            Path[] files = new Path[nFiles];
            for (int i=0; i<nDirs; i++) {
                dirs[i] = Files.createDirectory(top.resolve("dir" + i));
            }
            for (int i=0; i<nFiles; i++) {
                Path dir = dirs[rand.nextInt(nDirs)];
                files[i] = Files.createFile(dir.resolve("file" + i));
            }

            // register the directories (random sensitivity)
            register(dirs, watcher);

            // sleep a bit here to ensure that modification to the first file
            // can be detected by polling implementations (ie: last modified time
            // may not change otherwise).
            try { Thread.sleep(1000); } catch (InterruptedException e) { }

            // modify files and check that events are received
            for (int i=0; i<10; i++) {
                Path file = files[rand.nextInt(nFiles)];
                System.out.println("Modify: " + file);
                try (OutputStream out = Files.newOutputStream(file)) {
                    out.write(new byte[100]);
                }

                System.out.println("Waiting for event(s)...");
                boolean eventReceived = false;
                WatchKey key = watcher.take();
                do {
                    for (WatchEvent<?> event: key.pollEvents()) {
                        if (event.kind() != ENTRY_MODIFY)
                            throw new RuntimeException("Unexpected event: " + event);
                        Path name = ((WatchEvent<Path>)event).context();
                        if (name.equals(file.getFileName())) {
                            eventReceived = true;
                            break;
                        }
                    }
                    key.reset();
                    key = watcher.poll(1, TimeUnit.SECONDS);
                } while (key != null);

                // we should have received at least one ENTRY_MODIFY event
                if (eventReceived) {
                    System.out.println("Event OK");
                } else {
                    throw new RuntimeException("No ENTRY_MODIFY event received for " + file);
                }

                // re-register the directories to force changing their sensitivity
                // level
                register(dirs, watcher);
            }
        }
    }

    public static void main(String[] args) throws Exception {
        Path dir = TestUtil.createTemporaryDirectory();
        try {
            doTest(dir);
        } finally {
            TestUtil.removeAll(dir);
        }
    }
}