Standalone solution for loading a model out of a String using Xtext (instead of ParserHelper that depends on Junit/@test)

gistfile1.java

import java.io.BufferedWriter;
import java.io.File;
import java.io.FileWriter;
import java.io.IOException;
import java.util.UUID;

import org.eclipse.emf.common.util.URI;
import org.eclipse.emf.ecore.resource.Resource;
import org.eclipse.emf.ecore.resource.impl.ResourceSetImpl;
import org.xtext.example.mydsl.MmlStandaloneSetup;
import org.xtext.example.mydsl.mml.MMLModel;

public class MMLLoader {

	public static void main(String[] args) throws IOException {
		
		/*
		 * example of MML file
		 */
		String content = "datainput \"foo15.csv\"\n"
				+ "mlframework scikit-learn\n"
				+ "algorithm DT\n"
				+ "TrainingTest { pourcentageTraining 70 }\n"
				+ "recall\n"
				+ "";
		
		MMLModel mml = new MMLLoader().loadModel(content);
		
		// validaing the POC (we can traverse the model) 
		System.err.println("resource" + mml);
		System.err.println(mml.getInput() + " " + mml.getValidation());

	}

	public MMLModel loadModel(String content) {		
		
		try {
		    // first write the content into an MML file
		    File temp = File.createTempFile("mmlfile" + UUID.randomUUID(), ".mml"); 	    
		    URI uri = URI.createFileURI(temp.getAbsolutePath());		
		    BufferedWriter bw = new BufferedWriter(new FileWriter(temp));
		    bw.write(content);
		    bw.close();
		    // second load the resource	
		    MmlStandaloneSetup.doSetup();	
		    Resource res = new ResourceSetImpl().getResource(uri, true);		
	            MMLModel mml = (MMLModel) res.getContents().get(0); 
		    return mml;
		}
		
		catch (IOException e) {
		     System.err.println("Error loading MML model");
		     return null ; 
		}	   
		
		
	}


}

ParserHelper is a nice solution, but depends on @RunWith(XtextRunner)
So outside @Test methods, you cannot use it since dependency injection does not apply.

A workaround is to manually resolve dependency injection (as above).
It is also the solution I am usually relying on as part of the MDE/DSL/SPL course at University of Rennes 1: https://github.com/acherm/teaching-MDE-IL1819/blob/master/VideoGenTransformer/src/VideoGenHelper.xtend
Another solution is to edit .mwe2 file and generate a "Main" class:

language = StandardLanguage {
			name = "org.xtext.example.mydsl.Mml"
			fileExtensions = "mml"
...			
			generator = {
		        generateJavaMain = true 
		    }			
			
		} 

👍