Post Office

Bring your mail to the post office. It will be stored and a postal worker will deliver it. Because of the always recurring task in every project to store a mail and send it out with a worker I extracted this as a module.

This module is auto configured and depends on spring mail.

Currently only MongoDB is supported. For other databases implement the MailStorage interface.

Installation

The module is build by jitpack and can be downloaded with maven or gradle.

Add the jitpack repository:

<repositories>
    <repository>
        <id>jitpack.io</id>
        <url>https://jitpack.io</url>
    </repository>
</repositories>

And dependency:

<dependency>
    <groupId>com.github.nschwalbe</groupId>
    <artifactId>postoffice</artifactId>
    <version>develop-SNAPSHOT</version>
</dependency>

For more information like gradle see here: https://jitpack.io/#nschwalbe/postoffice

Configuration

Mail Server

Configure at least the spring.mail.host property. For more information see the spring mail configuration.

http://docs.spring.io/spring-boot/docs/current/reference/html/boot-features-email.html

Thread Pool

The default ThreadPoolTaskScheduler is used which comes by default with only one thread. To configure the scheduler define a configuration class which implements SchedulingConfigurer. For example:

@Configuration
@EnableScheduling
public class TaskExecutionConfig implements SchedulingConfigurer {

    @Override
    public void configureTasks(ScheduledTaskRegistrar taskRegistrar) {
        ThreadPoolTaskScheduler threadPoolTaskScheduler = new ThreadPoolTaskScheduler();
        threadPoolTaskScheduler.setPoolSize(3);
        threadPoolTaskScheduler.initialize();
        taskRegistrar.setTaskScheduler(threadPoolTaskScheduler);
    }
}

Usage

Define a Mailer class in your project and inject the MailService.

@Component
public class MyMailer {

    private final PostOffice postOffice;
    private final TemplateEngine templateEngine;
    private final MessageSource messageSource;

    @Autowired
    public MyMailer(PostOffice postOffice, TemplateEngine templateEngine, Environment environment, MessageSource messageSource) {
        this.postOffice = postOffice;
        this.templateEngine = templateEngine;
        this.messageSource = messageSource;
    }

    public void sendMail() {

        Context ctx = createContext();

        try {
            String subject = createSubject();
            String content = createContent(ctx);

            MimeMessage mimeMessage = postOffice.createMimeMessage(subject, from, to, content, true);

            postOffice.postMail(mimeMessage);

        } catch (Exception e) {
            log.error("Could not create mail!", e);
        }
    }
}