Example of a Quartz job that sends email notifications using FreeMarker templates from an application built with VRaptor. Dependencies: - vraptor-3.5.3 - vraptor-tasks-1.1.0 - vraptor-freemarker-1.1.2

AdminNotifierTask.java

package ...;

import br.com.caelum.vraptor.ioc.ApplicationScoped;
import br.com.caelum.vraptor.ioc.Container;
import br.com.caelum.vraptor.tasks.scheduler.Scheduled;
import br.com.caelum.vraptor.tasks.Task;
import java.util.List;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * @author Jardel Weyrich
 */
@ApplicationScoped
@Scheduled(
	initialDelay = AdminNotifierTask.STARTS_IN * 60 * 1000, // 2 minutes
	fixedRate = AdminNotifierTask.REPEAT_EVERY * 60 * 1000, // 2 minutes
	concurrent = false
)
public class AdminNotifierTask implements Task {
	
	public static final int STARTS_IN = 2; // minutes
	public static final int REPEAT_EVERY = 2; // minutes
	
	private static final Logger log = LoggerFactory.getLogger(AdminNotifierTask.class);
	
	private Container container;
	
	public AdminNotifierTask(Container container) {
		this.container = container;
	}
	
	@Override
	public void execute() {
		List<Event> pendingEvents = findAllPending();
		if (pendingEvents == null || pendingEvents.isEmpty()) {
			log.info("There are no pending events");
			return;
		}
		log.info(String.format("Found %d pending events.", pendingEvents.size()));
		final EventsEmailNotifier notifier = new EventsEmailNotifier(this.container);
		for (Event pe : pendingEvents) {
			boolean succeeded = notifier.notifyPendingEvent(pe);
			if (succeeded) {
				pe.setDidSendPendingNotification(true);
			}
		}
	}
	
	private List<Event> findAllPending() {
		// ...
	}

}

EventsEmailNotifier.java

package ...;

import br.com.caelum.vraptor.core.Localization;
import br.com.caelum.vraptor.environment.Environment;
import br.com.caelum.vraptor.freemarker.Freemarker;
import br.com.caelum.vraptor.freemarker.FreemarkerConfiguration;
import br.com.caelum.vraptor.freemarker.Template;
import br.com.caelum.vraptor.ioc.Container;
import br.com.caelum.vraptor.simplemail.Mailer;
import br.com.caelum.vraptor.simplemail.template.DefaultTemplateMailer;
import br.com.caelum.vraptor.simplemail.template.TemplateMailer;
import br.com.caelum.vraptor.util.test.MockLocalization;
import freemarker.template.TemplateException;
import java.io.IOException;
import java.io.StringWriter;
import java.util.HashMap;
import java.util.Map;
import javax.servlet.ServletContext;
import org.apache.commons.mail.Email;
import org.apache.commons.mail.EmailException;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * @author Jardel Weyrich
 */
public final class EventsEmailNotifier {

	private static final Logger log = LoggerFactory.getLogger(EventsEmailNotifier.class);
	
	private Container container;
	private Environment environment;
	private ServletContext context;
	private Mailer mailer; // We cannot use AsyncMailer here because of its dependencies.
	private Freemarker freemarker;
	private Localization localization;
	private TemplateMailer templates;
	
	public EventsEmailNotifier(Container container) {
		this.container = container;
		this.environment = this.container.instanceFor(Environment.class);
		this.context = this.container.instanceFor(ServletContext.class); // This is @ApplicationScoped so that's ok.
		this.mailer = this.container.instanceFor(Mailer.class);
		final FreemarkerConfiguration cfg = this.container.instanceFor(FreemarkerConfiguration.class);
		this.freemarker = new CustomFreemarkerEngine(cfg);
		this.localization = new MockLocalization(); // FIXME: This is ugly as hell.
		this.templates = new DefaultTemplateMailer(
				this.localization, this.freemarker, this.context, this.environment);
	}

	// Adapted from br.com.caelum.vraptor.freemarker.FreemarkerEngine
	public final class CustomFreemarkerEngine implements Freemarker {
		
		private final FreemarkerConfiguration cfg;

		public CustomFreemarkerEngine(FreemarkerConfiguration cfg) {
			this.cfg = cfg;
		}

		@Override
		public Template use(String name) throws IOException {
			freemarker.template.Template template = cfg.getConfiguration().getTemplate(name + ".ftl");
			return new CustomDefaultTemplate(template);
		}
	}
	
	// Adapted from br.com.caelum.vraptor.freemarker.DefaultTemplate
	public final class CustomDefaultTemplate implements Template {

		private final freemarker.template.Template template;
		private final Map<String, Object> root = new HashMap<>();

		public CustomDefaultTemplate(freemarker.template.Template template) {
			this.template = template;
		}

		@Override
		public void render() throws IOException, TemplateException {
			// Disable render to servlet response
			throw new UnsupportedOperationException();
		}

		@Override
		public Template with(String key, Object value) {
			root.put(key, value);
			return this;
		}

		@Override
		public String getContent() throws IOException, TemplateException {
			StringWriter writer = new StringWriter();
			freemarker.core.Environment processingEnv = template.createProcessingEnvironment(root, writer);
			processingEnv.setOutputEncoding("UTF-8");
			processingEnv.process();
			writer.flush();

			return writer.getBuffer().toString();
		}
	}
	
	// NOTE: One would prefer to use events and listeners. Example:
	//    @Inject @Any private Event<Something> somethingEvent;
	//    public void eventFired(@Observes Something something) { /* ... */ }
	public boolean notifyPendingEvent(final Event event) {
		final String toName = "Admin"
		final String toEmail = "root@localhost";
		final String subject = "Test";
		final Email email = this.templates
				.template("test_email_template")
				.to(toName, toEmail);
		email.setSubject(subject);
		try {
			mailer.send(email);
		} catch (EmailException ex) {
			log.error(null, ex);
			return false;
		}
		return true;
	}
	
}

want to Build Notifier Servlet using Email templates can some one help me on this