Example usage for java.nio.file WatchService poll

Introduction

In this page you can find the example usage for java.nio.file WatchService poll.

Prototype

WatchKey poll(long timeout, TimeUnit unit) throws InterruptedException;

Source Link

Document

Retrieves and removes the next watch key, waiting if necessary up to the specified wait time if none are yet present.

Usage

From source file:cz.muni.fi.pb138.cvmanager.service.PDFgenerator.java

/**
 * By external calling pdflatex function of laTex generates pdf curriculum vitae document from .tex file
 * @param username name of user whose is the CV
 * @return language to export (sk/en)/*from ww w .  ja  va  2 s. com*/
 * @throws IOException
 * @throws InterruptedException
 * @throws NullPointerException
 */
public InputStream latexToPdf(String username) throws IOException, InterruptedException, NullPointerException {
    ProcessBuilder pb = new ProcessBuilder("pdflatex", username + "_cv.tex", "--output-directory=");
    File file = new File("cvxml/");
    pb.directory(file);
    Process p = pb.start();

    WatchService watcher = FileSystems.getDefault().newWatchService();
    Path dir = Paths.get("cvxml/");
    dir.register(watcher, ENTRY_CREATE, ENTRY_MODIFY);

    while (true) {
        // wait for a key to be available for 10 seconds
        WatchKey key = watcher.poll(10000L, TimeUnit.MILLISECONDS);
        if (key == null) {
            break;
        }

        for (WatchEvent<?> event : key.pollEvents()) {
            // get event type
            WatchEvent.Kind<?> kind = event.kind();

            // get file name
            @SuppressWarnings("unchecked")
            WatchEvent<Path> ev = (WatchEvent<Path>) event;
            Path fileName = ev.context();

            System.out.println(kind.name() + ": " + fileName);
        }

        boolean valid = key.reset();
        if (!valid) {
            break;
        }
    }

    System.out.println("end of cycle");

    File pdf = new File("cvxml/" + username + "_cv.pdf");

    return new FileInputStream(pdf);
}

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From source file:org.springframework.cloud.gcp.stream.binder.pubsub.PubSubEmulator.java

/**
 * Wait until a PubSub emulator configuration file is updated.
 * Fail if the file does not update after 1 second.
 * @param watchService the watch-service to poll
 * @throws InterruptedException which should interrupt the peaceful slumber and bubble up
 * to fail the test.//from   w w w . j a v a 2s  . co m
 */
private void updateConfig(WatchService watchService) throws InterruptedException {
    int attempts = 10;
    while (--attempts >= 0) {
        WatchKey key = watchService.poll(100, TimeUnit.MILLISECONDS);

        if (key != null) {
            Optional<Path> configFilePath = key.pollEvents().stream().map((event) -> (Path) event.context())
                    .filter((path) -> ENV_FILE_NAME.equals(path.toString())).findAny();
            if (configFilePath.isPresent()) {
                return;
            }
        }
    }

    fail("Configuration file update could not be detected");
}

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