public List<Course> findByKeywords(long groupId,String keywords, int start, int end, OrderByComparator<Course> orderByComparator){
	DynamicQuery query = dynamicQuery().add(RestrictionsFactoryUtil.eq("groupId", groupId));
	if (Validator.isNotNull(keywords)) {
		 Junction disjunction = RestrictionsFactoryUtil.disjunction()
				.add(
						RestrictionsFactoryUtil.like("name",'%'+ keywords+'%')
				).add(
						RestrictionsFactoryUtil.like("description",'%'+ keywords+'%')
				);
		 query.add(disjunction);
	}
	return dynamicQuery(query, start, end, orderByComparator);
}