UniqueNameType returns talendFile::ElementParameterType :STRING;

/**
 * Use this class to register components to be used at runtime / without the Equinox extension registry.
 */
public class JobScriptRuntimeModule extends  org.talend.metalanguage.jobscript.AbstractJobScriptRuntimeMo dule {

    /*
     * (non-Javadoc)
     * 
     * @see  org.eclipse.xtext.service.DefaultRuntimeModule#bindIValueCon verterService()
     */
    @Override
    public Class<? extends IValueConverterService> bindIValueConverterService() {
        return JobScriptValueConverters.class;
    }

    static public class JobScriptValueConverters extends DefaultTerminalConverters {

        @ValueConverter(rule = "UniqueNameType")
        public IValueConverter<ElementParameterType> UniqueNameType() {
            return new IValueConverter<ElementParameterType>() {

                public ElementParameterType toValue(String string, AbstractNode node) throws ValueConverterException {
                    ElementParameterType elementParameterType = TalendFileFactory.eINSTANCE.createElementParameterType();
                    elementParameterType.setField("TEXT");
                    elementParameterType.setName("UNIQUE_NAME");
                    elementParameterType.setValue(string);
                    return elementParameterType;
                }

                public String toString(ElementParameterType value) throws ValueConverterException {
                    return value.getValue();
                }
            };
        }
    }
}

private static AbstractElement getGrammarElement(EObject eObj){
	AbstractNode node = NodeUtil.getNode(eObj);
	AbstractElement grammarElement = (AbstractElement) node.getGrammarElement();
	return grammarElement;
}

UniqueNameType returns talendFile::ElementParameterType : 
{talendFile::ElementParameterType} 
  		value=UNIQUE_NAME_RULE
//  		name="UNIQUE_NAME"
//  		field="TEXT"
;

UNIQUE_NAME_RULE : STRING;

public class JobScriptRuntimeModule extends org.talend.metalanguage.jobscript.AbstractJobScriptRuntimeModule {

    @Override
    public Class<? extends IAstFactory> bindIAstFactory() {
        return JobScriptAstFactory.class;
    }

    static public class JobScriptAstFactory extends DefaultEcoreElementFactory {

        @Override
        public void set(EObject object, String feature, Object value, String ruleName, AbstractNode node)
                throws ValueConverterException {
            super.set(object, feature, value, ruleName, node);
            if ("UNIQUE_NAME_RULE".equals(ruleName)) {
                ElementParameterType elemParamType = (ElementParameterType) object;
                elemParamType.setName("UNIQUE_NAME");
                elemParamType.setField("TEXT");
            }
        }
    }
}