Keep DAO clean using Hibernate Criteria /Criterion

Hibernate Criteria/Criterion classes helps reduce the number of lines in DAO code. Have private methods returning the specific Criterion and in public DAO method compose complex criteria by calling private methods.

public List getSprints(Date afterDate, Date beforeDate) {
Criteria criteria = getSession().createCriteria(MyEntity.class);
criteria.add(getDateCriteria(afterDate, beforeDate));
return criteria.list();
}

public List getEntityByType(String type, Date afterDate, Date beforeDate) {
Criteria criteria = getSession().createCriteria(MyEntity.class);
criteria.add(getDateCriteria(afterDate, beforeDate));
criteria.add(Restrictions.eq("type", type));
return criteria.list();
}

private Criterion getDateCriteria(Date afterDate, Date beforeDate) {
if(beforeDate == null) { // Is parameter provided ?
beforeDate = new Date();
}
if(afterDate == null) { // Is parameter provided
Calendar cal = Calendar.getInstance();
cal.add(Calendar.YEAR, -1);
afterDate = cal.getTime();
}

Criterion start = Restrictions.between("startDate", beforeDate, afterDate);
Criterion end = Restrictions.between("endDate", beforeDate, afterDate);
return Restrictions.or(start, end);
}