У меня проблемы с преобразованием запроса JPA в использование Criteria API
У меня есть следующий запрос, который пытается найти ServiceUser, соответствующий переданному параметру адреса. ServiceUser - это абстрактная сущность с конкретными подклассами Child и Adult. Я использую стратегию объединенного наследования в классе ServiceUser.
Все работает нормально, когда я вызываю этот метод.
public Set<T> findByAddress(Address address) {
Query query = manager.createQuery("SELECT distinct s FROM ServiceUser AS s JOIN s.addressHistory as h where h = :address");
query.setParameter("address", address);
HashSet<T> result = new HashSet<T>();
for (Object s : query.getResultList()) {
// tClass is the runtime type of the generic session bean.
if (this.tClass.isInstance(s)) {
result.add((T) s);
}
}
return result;
}
Но если я попытаюсь заменить функцию следующим, использующим сгенерированную метамодель и типизированный запрос, я получу исключение
public Set<T> findByAddress(Address address) {
CriteriaBuilder cb = manager.getCriteriaBuilder();
CriteriaQuery<ServiceUser> cq = cb.createQuery(ServiceUser.class);
Root<ServiceUser> su = cq.from(ServiceUser.class);
Join<ServiceUser, Address> addressHistory = su.join(ServiceUser_.addressHistory);
cq.select(su).distinct(true).where(cb.equal(addressHistory, cb.parameter(Address.class, "address")));
TypedQuery<ServiceUser> q = manager.createQuery(cq);
q.setParameter("address", address);
HashSet<T> result = new HashSet<T>();
for (ServiceUser s : q.getResultList()) {
// tClass is the runtime type of the generic session bean.
if (this.tClass.isInstance(s)) {
result.add((T) s);
}
}
return result;
}
Вот эта трассировка стека, будет входить в Eclipslink. Кажется, создается исключение NulPointerException, но я не уверен, почему?
/**
Test : shouldBeAbleToFindChildByAddress()
uk.gov.sunderland.ccms.model.bean.ChildService.findByAddress(Address[id=1,lineOne=7,lineTwo=Camberwell Way,lineThree=Moorside,lineFour=Sunderland,postcode=SR7 3XN])
[EL Finer]: 2010-12-20 12:39:42.89--ServerSession(7055953)--Thread(Thread[pool-52-thread-1,5,grizzly-kernel])--client acquired
[EL Finer]: 2010-12-20 12:39:42.89--UnitOfWork(22763294)--Thread(Thread[pool-52-thread-1,5,grizzly-kernel])--TX binding to tx mgr, status=STATUS_ACTIVE
[EL Finest]: 2010-12-20 12:39:42.89--UnitOfWork(22763294)--Thread(Thread[pool-52-thread-1,5,grizzly-kernel])--Execute query ReadObjectQuery(referenceClass=Address sql="SELECT ID, LINE_TWO, LINE_THREE, LINE_ONE, LINE_FOUR, POSTCODE FROM ADDRESS WHERE (ID = ?)")
[EL Finest]: 2010-12-20 12:39:42.906--UnitOfWork(22763294)--Thread(Thread[pool-52-thread-1,5,grizzly-kernel])--Execute query ReadAllQuery(referenceClass=ServiceUser )
[EL Finest]: 2010-12-20 12:39:42.906--ServerSession(7055953)--Thread(Thread[pool-52-thread-1,5,grizzly-kernel])--reconnecting to external connection pool
[EL Fine]: 2010-12-20 12:39:42.906--ServerSession(7055953)--Connection(32184426)--Thread(Thread[pool-52-thread-1,5,grizzly-kernel])--SELECT DISTINCT t2.SERVICE_USER_TYPE FROM ADDRESS t0, SERVICE_USER t2, SERVICE_USER_ADDRESS t1 WHERE ((? = t0.ID) AND ((t1.SERVICE_USER_ID = t2.ID) AND (t0.ID = t1.ADDRESS_ID)))
bind => [1]
[EL Finer]: 2010-12-20 12:39:42.906--UnitOfWork(22763294)--Thread(Thread[pool-52-thread-1,5,grizzly-kernel])--class uk.gov.sunderland.ccms.model.entity.Adult
[EL Finest]: 2010-12-20 12:39:42.906--ServerSession(7055953)--Thread(Thread[pool-52-thread-1,5,grizzly-kernel])--reconnecting to external connection pool
[EL Fine]: 2010-12-20 12:39:42.906--ServerSession(7055953)--Connection(29495316)--Thread(Thread[pool-52-thread-1,5,grizzly-kernel])--SELECT DISTINCT t0.ID, t0.SERVICE_USER_TYPE, t0.TITLE, t0.DOB, t0.GENDER, t0.DISABILITY, t0.ETHNICITY, t1.ID, t1.EMPLOYMENT, t1.INFO_PACK_REQUIRED, t1.HOME_PHONE, t1.OTHER_LANGUAGE, t1.REFERRER, t1.MOBILE_PHONE, t1.LONE_PARENT, t1.GP_PRACTICE, t1.CONTACTABLE, t1.WORK_PHONE, t1.BABY_DUE_DATE, t1.ENGLISH_LEVEL FROM SERVICE_USER_ADDRESS t3, ADDRESS t2, ADULT t1, SERVICE_USER t0 WHERE (((? = t2.ID) AND ((t1.ID = t0.ID) AND (t0.SERVICE_USER_TYPE = ?))) AND ((t3.SERVICE_USER_ID = t0.ID) AND (t2.ID = t3.ADDRESS_ID)))
bind => [1, 1]
[EL Warning]: 2010-12-20 12:39:42.906--UnitOfWork(22763294)--Thread(Thread[pool-52-thread-1,5,grizzly-kernel])--java.lang.NullPointerException
at org.eclipse.persistence.descriptors.InheritancePolicy.selectAllRowUsingDefaultMultipleTableSubclassRead(InheritancePolicy.java:1355)
at org.eclipse.persistence.descriptors.InheritancePolicy.selectAllRowUsingMultipleTableSubclassRead(InheritancePolicy.java:1396)
at org.eclipse.persistence.internal.queries.ExpressionQueryMechanism.selectAllRows(ExpressionQueryMechanism.java:2493)
at org.eclipse.persistence.queries.ReadAllQuery.executeObjectLevelReadQuery(ReadAllQuery.java:407)
at org.eclipse.persistence.queries.ObjectLevelReadQuery.executeDatabaseQuery(ObjectLevelReadQuery.java:1074)
at org.eclipse.persistence.queries.DatabaseQuery.execute(DatabaseQuery.java:736)
at org.eclipse.persistence.queries.ObjectLevelReadQuery.execute(ObjectLevelReadQuery.java:1034)
at org.eclipse.persistence.queries.ReadAllQuery.execute(ReadAllQuery.java:380)
at org.eclipse.persistence.queries.ObjectLevelReadQuery.executeInUnitOfWork(ObjectLevelReadQuery.java:1112)
at org.eclipse.persistence.internal.sessions.UnitOfWorkImpl.internalExecuteQuery(UnitOfWorkImpl.java:2909)
at org.eclipse.persistence.internal.sessions.AbstractSession.executeQuery(AbstractSession.java:1291)
at org.eclipse.persistence.internal.sessions.AbstractSession.executeQuery(AbstractSession.java:1273)
at org.eclipse.persistence.internal.sessions.AbstractSession.executeQuery(AbstractSession.java:1247)
at org.eclipse.persistence.internal.jpa.EJBQueryImpl.executeReadQuery(EJBQueryImpl.java:479)
at org.eclipse.persistence.internal.jpa.EJBQueryImpl.getResultList(EJBQueryImpl.java:714)
*/
Глядя на SQL, который выдается с ошибочным API-запросом критериев, и сравнивая с SQL, который выдается, когда я выполняю запрос с запросом строки jpa.
Критерий запроса
SELECT DISTINCT t0.ID, t0.SERVICE_USER_TYPE, t0.TITLE, t0.DOB, t0.GENDER, t0.DISABILITY, t0.ETHNICITY, t1.ID, t1.EMPLOYMENT, t1.INFO_PACK_REQUIRED, t1.HOME_PHONE, t1.OTHER_LANGUAGE, t1.REFERRER, t1.MOBILE_PHONE, t1.LONE_PARENT, t1.GP_PRACTICE, t1.CONTACTABLE, t1.WORK_PHONE, t1.BABY_DUE_DATE, t1.ENGLISH_LEVEL
FROM SERVICE_USER_ADDRESS t3, ADDRESS t2, ADULT t1, SERVICE_USER t0
WHERE (((? = t2.ID) AND ((t1.ID = t0.ID) AND (t0.SERVICE_USER_TYPE = ?)))
AND ((t3.SERVICE_USER_ID = t0.ID) AND (t2.ID = t3.ADDRESS_ID)))
JPA String Query
SELECT DISTINCT t0.ID, t0.SERVICE_USER_TYPE, t0.TITLE, t0.DOB, t0.GENDER, t0.DISABILITY, t0.ETHNICITY, t1.ID, t1.EMPLOYMENT, t1.INFO_PACK_REQUIRED, t1.HOME_PHONE, t1.OTHER_LANGUAGE, t1.REFERRER, t1.MOBILE_PHONE, t1.LONE_PARENT, t1.GP_PRACTICE, t1.CONTACTABLE, t1.WORK_PHONE, t1.BABY_DUE_DATE, t1.ENGLISH_LEVEL
FROM SERVICE_USER_ADDRESS t3, ADDRESS t2, ADULT t1, SERVICE_USER t0
WHERE (((? = t2.ID) AND ((t1.ID = t0.ID) AND (t0.SERVICE_USER_TYPE = ?)))
AND ((t3.SERVICE_USER_ID = t0.ID) AND (t2.ID = t3.ADDRESS_ID)))
и
SELECT DISTINCT t0.ID, t0.SERVICE_USER_TYPE, t0.TITLE, t0.DOB, t0.GENDER, t0.DISABILITY, t0.ETHNICITY, t1.ID
FROM SERVICE_USER_ADDRESS t3, ADDRESS t2, CHILD t1, SERVICE_USER t0 WHERE (((? = t2.ID) AND ((t1.ID = t0.ID) AND (t0.SERVICE_USER_TYPE = ?))) AND ((t3.SERVICE_USER_ID = t0.ID) AND (t2.ID = t3.ADDRESS_ID)))
Я вижу, что первая часть, которая имеет дело с подклассом Adult в ServiceUser, идентична в обоих случаях, но когда дело доходит до подкласса Child, запрос Criteria выдает
[EL Warning]: 2010-12-20 )--java.lang.NullPointerException
at org.eclipse.persistence.descriptors.InheritancePolicy.selectAllRowUsingDefaultMultipleTableSubclassRead(InheritancePolicy.java:1355)
Может ли это быть ошибкой в Eclipselink?