private void createGenModel(final EPackage rootPackage, final String ecoreLocation,
        final String genModelLocation) {

        GenModel genModel = GenModelFactory.eINSTANCE.createGenModel();
        genModel.setComplianceLevel(GenJDKLevel.JDK70_LITERAL);
        genModel.setModelDirectory(Constants.GEN_MODEL_MODEL_DIR.getValue());
        genModel.getForeignModel().add(new Path(ecoreLocation).lastSegment());
        genModel.setModelName(Constants.GEN_MODEL_MODEL_NAME.getValue());
        genModel.setRootExtendsInterface(Constants.GEN_MODEL_EXTENDS_INTERFACE.getValue());
        genModel.initialize(Collections.singleton(rootPackage));

        GenPackage genPackage = (GenPackage)genModel.getGenPackages().get(0);
        genPackage.setPrefix(Constants.GEN_MODEL_PACKAGE_PREFIX.getValue());

        try {
            URI genModelURI = URI.createFileURI(genModelLocation);
            final XMIResourceImpl genModelResource = new XMIResourceImpl(genModelURI);
            genModelResource.getDefaultSaveOptions().put(XMLResource.OPTION_ENCODING,
                Constants.GEN_MODEL_XML_ENCODING.getValue());
            genModelResource.getContents().add(genModel);
            genModelResource.save(Collections.EMPTY_MAP);
        } catch (IOException e) {
            String msg = null;
            final String genModelLocationCleaned = LogUtil.stripForgeChars(genModelLocation);
            if (e instanceof FileNotFoundException) {
                msg = "Unable to open output file " + genModelLocationCleaned;
            } else {
                msg = "Unexpected IO Exception writing " + genModelLocationCleaned;
            }
            LOGGER.error(msg, e);
            throw new RuntimeException(msg, e);
        }
    }