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package org.glassfish.jersey.examples.reload;
import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.URI;
import java.util.Timer;
import java.util.TimerTask;
import java.util.logging.Level;
import java.util.logging.Logger;
import org.glassfish.jersey.grizzly2.httpserver.GrizzlyHttpServerFactory;
import org.glassfish.jersey.server.ResourceConfig;
import org.glassfish.jersey.server.spi.Container;
import org.glassfish.jersey.server.spi.ContainerLifecycleListener;
import org.glassfish.grizzly.http.server.HttpServer;
/**
* Reload example application.
*
* A {@link ContainerLifecycleListener container listener} gets registered
* with the application. Upon application startup notification, the listener schedules
* a new {@link TimerTask timer task} to check a text file called {@code resources}
* every 2 seconds. When the text file change is detected, the application gets reloaded with
* a new {@link ResourceConfig resource configuration} including all
* resource classes listed in that file.
*
* @author Jakub Podlesak (jakub.podlesak at oracle.com)
*/
public class App {
private static final Logger LOGGER = Logger.getLogger(App.class.getName());
private static final URI BASE_URI = URI.create("http://localhost:8080/flights/");
public static final String ROOT_PATH = "arrivals";
public static final String CONFIG_FILENAME = "resources";
public static final long REFRESH_PERIOD_MS = 2000;
static Container container;
// @todo Java SE 7 - use java.nio.file.WatchService
static class FileCheckTask extends TimerTask {
long lastModified;
FileCheckTask(final long lastModified) {
this.lastModified = lastModified;
}
@Override
public void run() {
final File configFile = new File(CONFIG_FILENAME);
final long actualLastModified = configFile.lastModified();
if (lastModified < actualLastModified) {
lastModified = actualLastModified;
reloadApp(configFile);
}
}
private void reloadApp(final File configFile) {
LOGGER.info("Reloading resource classes:");
final ResourceConfig rc = new ResourceConfig();
try {
try (BufferedReader r = new BufferedReader(new InputStreamReader(new FileInputStream(configFile), "UTF-8"))) {
while (r.ready()) {
final String className = r.readLine();
if (!className.startsWith("#")) {
try {
rc.registerClasses(Class.forName(className));
LOGGER.info(String.format(" + loaded class %s.\n", className));
} catch (final ClassNotFoundException ex) {
LOGGER.info(String.format(" ! class %s not found.\n", className));
}
} else {
LOGGER.info(String.format(" - ignored class %s\n", className.substring(1)));
}
}
}
} catch (final Exception ex) {
Logger.getLogger(App.class.getName()).log(Level.SEVERE, null, ex);
}
App.container.reload(rc);
}
}
public static void main(final String[] args) {
try {
LOGGER.info("Resource Config Reload Jersey Example App");
final ResourceConfig resourceConfig = new ResourceConfig(ArrivalsResource.class);
resourceConfig.registerInstances(new ContainerLifecycleListener() {
@Override
public void onStartup(final Container container) {
App.container = container;
final Timer t = new Timer(true);
t.scheduleAtFixedRate(new FileCheckTask(0), 0, REFRESH_PERIOD_MS);
}
@Override
public void onReload(final Container container) {
System.out.println("Application has been reloaded!");
}
@Override
public void onShutdown(final Container container) {
// ignore
}
});
final HttpServer server = GrizzlyHttpServerFactory.createHttpServer(BASE_URI, resourceConfig);
System.out.println(String.format("Application started.\nTry out %s%s\nHit enter to stop it...", BASE_URI, ROOT_PATH));
System.in.read();
server.shutdownNow();
} catch (final IOException ex) {
Logger.getLogger(App.class.getName()).log(Level.SEVERE, null, ex);
}
}
}