`QueryCalculator.java`
`01 package trail.entity.query; 02 03 import trail.entity.beans.*; 04 import javax.ejb.*; 05 import javax.persistence.*; 06 import javax.annotation.Resource; 07 import java.util.*; 08 09 @Stateless 10 public class QueryCalculator implements Calculator { 11 12 @PersistenceContext 13 protected EntityManager em; 14 15 public Collection <Fund> getFunds () { 16 return em.createQuery("from Fund f").getResultList(); 17 } 18 public Collection <Investor> getInvestors () { 19 return em.createQuery("from Investor p").getResultList(); 20 } 21 public Collection <TimedRecord> getRecords () { 22 return em.createQuery("from TimedRecord r order by r.id desc").getResultList(); 23 } 24 public Collection <TimedRecord> filterRecords (double low, double high) { 25 return em.createQuery( 26 "from TimedRecord r where r.result > :low AND r.result < :high") 27 .setParameter ("low", new Double (low)) 28 .setParameter ("high", new Double (high)) 29 .getResultList(); 30 } 31 32 }`