code: protected Predicate createEqual(Path root, CriteriaQuery<?> query, CriteriaBuilder cb, String propertyPath,
                                      Object argument, PersistenceContext context)
      {
          return cb.equal(root.get(propertyPath), argument);
      }
docs: Apply an "equal" constraint to the named property.
  
  
  @param query
  @param propertyPath property name prefixed with an association alias
  @param argument     value
  @param context
  @return Predicate