Overview

This projects aims to bring mjml (mailjet markup language) to the java world. Because mjml is only provided as a bunch of javascript packages, the only way to access it from Java is to run the original javascript code within Nashorn and to bridge calls between these two.

Get It

Releases are maintained via jcenter. Snapshots are available via jitpack.

Gradle

repositories {
    jcenter()
}

dependencies {
    compile 'com.wescale:mjml-processor:1.0.4'
}

Maven

<dependency>
    <groupId>com.wescale</groupId>
    <artifactId>mjml-processor</artifactId>
    <version>1.0.4</version>
</dependency>
...
<repositories>
    <repository>
        <snapshots>
            <enabled>false</enabled>
        </snapshots>
        <id>jcenter</id>
        <name>bintray</name>
        <url>https://jcenter.bintray.com</url>
    </repository>
</repositories>
<pluginRepositories>
    <pluginRepository>
        <snapshots>
            <enabled>false</enabled>
        </snapshots>
        <id>jcenter</id>
        <name>bintray-plugins</name>
        <url>https://jcenter.bintray.com</url>
    </pluginRepository>
</pluginRepositories>
...

Usage

Include the package and use it as follows

import com.wescale.mjml;

// ...

MjmlProcessor mjmlProcessor = MjmlProcessor.create();
String template = "<mjml><mj-body><mj-text>Hello World</mj-text></mj-body></mjml>";
MjmlProcessorResult mjmlProcessorResult = mjmlProcessor.process(template);
String html = mjmlProcessorResult.getHtml();

Keep a newly created instance of MjmlProcessor as long as possible. Read the performance section for details.

Performance

You should be aware that creating an instance of MjmlProcessor creates a new Nashorn instance, loads about 4MB of javascript and parses/compiles this into bytecode. This leads to two consequences

• creating an instance of MjmlProcessor lasts a quite amount of time (few seconds)
• the first calls to this code are rather slow because the JVM optimizes the javascript bytecode over time

This means that you should really take care of not throwing away this instance quickly. Create it and hold it as long as you can and the performance of calling process will increase dramatically over time. You could even think of using an object pool to handle multiple threads processing mjml markup.