Epsilon Transformation Language Demo

About

The Epsilon Transformation Language is an eclipse extension for model transformations. Despite many code snippets available online, it is hard to find a standalone demo that is:

• well documented
• minimal
• working
• fully standalone (no eclipse required, builds into self-contained jar)

I therefore parted from the standalone examples of Hyacinths fork and the official repo. After a lot of cherry-picking and refactoring, I ended up with this simple demo project.

Changelog

• Added this markdown file, as a place to start.
• Decluttered original repo from everything, not of particular interest for a minimal ETL demo.
  • Removed non-standalone sibling projects
  • Removed non-ETL examples
  • Removed irrelevant / unused etl / meta-models / xmi files.
  • Removed eclipse / html / bloat / meta files
• Added code
  • Launcher class for enhanced separation of concerns
  • Util class to correctly resolve metamodel / etl-rule as java resources
  • Util class to detect if code is executed from JAR or natively
• Cleaned up and added many comments to explain what the code actually does.
• Fixed maven configuration
  • Refactored project structure, so it complies to maven conventions
  • Pom entry to correctly reference main class for direct launch
  • Pom configuration for creation of self-contained JAR

Scenario

The code of this demo project transforms a Tree input model into a Tree output model. Specifically, it copies every node of the input model and prefixes it's label by copyOf.

• Example output model:

<?xml version="1.0" encoding="ASCII"?>
<Tree xmi:version="2.0" xmlns:xmi="http://www.omg.org/XMI" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="TreeDsl" xsi:schemaLocation="TreeDsl file:///Users/schieder/Code/EtlStandaloneExample/target/classes/metamodels/Tree.ecore" label="CopyOfa">
  <children label="CopyOfb">
    <children label="CopyOfc"/>
  </children>
</Tree>

• The syntax of tree models is defined by an ecore meta-model. The input model (Tree.xmi), as well as the generated deep copy conform to this meta-model.

Hands-On

This is a true standalone project. You do not need an IDE to run this, especially you do not need eclipse.

Clone instructions

git clone https://github.com/kartoffelquadrat/EtlTrueStandalone.git

Run instructions

You can either directly run the code, or first build a self-contained jar.

Direct launch

• Update the input / output model locations in pom.xml:87/88:

<argument>/Users/schieder/Code/EtlStandaloneExample/Tree.xmi</argument>
<argument>/Users/schieder/Desktop/Copy.xmi</argument>

• Then run the demo:
  mvn clean package exec:java

Launch from JAR

• Build a self-contained jar:
  mvn clean package

• Run the self-contained jar with:
  java -jar target/EtlPlayground.jar /Users/schieder/Code/EtlTrueStandalone/Tree.xmi /Users/schieder/Desktop/Copy.xmi

Again, don't forget to update the runtime arguments.

Contact / Pull Requests

• Modifications: Maximilian Schiedermeier
• Github: Kartoffelquadrat
• Webpage: https://www.cs.mcgill.ca/~mschie3
• Original license, usage of official ETL-demo code snippets approved by authors.