EMF Compare FAQ

Users

My model is compared as a text-file, how can EMF compare know what file it should handle ?

Q : My model is compared as a text-file, how can EMF compare know what file it should handle ?

A : EMF compare uses a content-type to know if it should be started or not. By default this content-type is composed of *.ecore and *.uml file but you may add your own extension using the Preferences view / Global / Content-types and adding your file extension in the "Model File" content-type.

Developpers

How can I programatically add my model file extension in EMF Compare so that it is called automatically ?

Q : How can I programatically add my model file extension in EMF Compare so that it is called automatically ?

A : Using the "Model File" content-type defined with EMF Compare, here is a sample from a plugin.xml:

 <extension
        point="org.eclipse.core.contenttype.contentTypes">
     <file-association
           content-type="org.eclipse.emf.compare.ui.contenttype.ModelContentType"
           file-extensions="uml13"
           file-names="*"/>
  </extension>

Is EMF Compare, as EMF, able to run outside of Eclispe ?

Q : Is EMF Compare able to compare "in-memory" objects, and can it be run without Eclispe ?

A: Yes, here is a snippet doing that:

 /**
 * This application will try and launch an headless model comparison.
 * 
 * @author Cedric Brun <a href="mailto:cedric.brun@obeo.fr">cedric.brun@obeo.fr</a>
 */
public final class ExampleLauncher {
	/**
	 * This class doesn't need to be instantiated.
	 */
	private ExampleLauncher() {
		// prevents instantiation
	}

	/**
	 * Launcher of this application.
	 * 
	 * @param args
	 *            Arguments of the launch.
	 */
	public static void main(String[] args) {
		if (args.length == 2 && new File(args[0]).canRead() && new File(args[1]).canRead()) {
			// Creates the resourceSet where we'll load the models
			final ResourceSet resourceSet = new ResourceSetImpl();
			try {
				// Loads the two models passed as arguments
				final EObject model1 = ModelUtils.load(new File(args[0]), resourceSet);
				final EObject model2 = ModelUtils.load(new File(args[1]), resourceSet);
				
				// Creates the match then the diff model for those two models
				final MatchModel match = new DifferencesServices().modelMatch(model1, model2, new NullProgressMonitor());
				final DiffModel diff = new DiffMaker().doDiff(match);
				
				// Prints the results
				try {
					System.out.println(ModelUtils.serialize(match));
					System.out.println(ModelUtils.serialize(diff));
				} catch (IOException e) {
					e.printStackTrace();
				}
				
//				System.out.println("saving diff as \"result.diff\"");
//				ModelUtils.save(diff, "result.diff");
//				System.out.println("saving match as \"result.match\"");
//				ModelUtils.save(match, "result.match");
				
				// Serializes the result as "result.emfdiff" in the directory this class has been called from.
				System.out.println("saving emfdiff as \"result.emfdiff\""); //$NON-NLS-1$
				final ModelInputSnapshot snapshot = DiffFactory.eINSTANCE.createModelInputSnapshot();
				snapshot.setDate(Calendar.getInstance().getTime());
				snapshot.setMatch(match);
				snapshot.setDiff(diff);
				ModelUtils.save(snapshot, "result.emfdiff"); //$NON-NLS-1$
			} catch (IOException e) {
				// shouldn't be thrown
				e.printStackTrace();
			} catch (InterruptedException e) {
				e.printStackTrace();
			}
		} else {
			System.out.println("usage : Launcher <Model1> <Model2>"); //$NON-NLS-1$
		}
	}
}