How can I perform a JPA query for another object?
in the normal case we do :
public interface Object1Repository extends JpaRepository<Object1, Long> { public List<Object2> findById(Long id);
}
but here i want to do the samething with another object (object2) :
public interface Object1Repository extends JpaRepository<Object1, Long> {
public List<Object2> findById(Long id); }
Related
I am running jee-2019-06 version of Eclipse. Here is my Model-Bean-Facade structure:
I am not including getters/setters for brevity.
My Identifiable:
/** Identifiable interface for Entities; used for DAO - Service transitions. */
public interface Identifiable<T extends Serializable> extends Serializable {
public T getId(); // identifiable field
public String getTitle(); // user friendly name (maybe different from actual entity's name)
public String getName(); // every entity has a name
public String getDescription(); // every entity should have a description
}
My Abstract Bean:
public abstract class AbstractBean<T extends Identifiable<?>> {
protected final transient Logger log = Logger.getLogger(this.getClass());
private final Class<T> clazz;
private T model;
public AbstractBean(final Class<T> clazz) {
this.clazz = clazz;
}
protected T createInstance() {
try {
return this.clazz.newInstance();
} catch (InstantiationException | IllegalAccessException e) {
this.log.error("[" + this.getClass().getSimpleName() + ".createInstance()] : Error : {} {}", e.getMessage(), e);
return null;
}
}
protected AbstractFacade<T> getFacade() {
return null;
}
}
My Abstract Facade:
#Transactional
public abstract class AbstractFacade<T extends Identifiable<?>> {
protected final transient Logger log = Logger.getLogger(this.getClass());
protected final Class<T> clazz;
public AbstractFacade(final Class<T> clazz) {
this.clazz = clazz;
}
}
My Bean:
#Named
#ViewScoped
public class CarBean extends AbstractBean<Car> {
#Inject
private CarFacade facade;
public CarBean(){
super(Car.class);
}
#Override
public CarFacade getFacade() {
return this.facade;
}
}
My AbstractEntity:
#MappedSuperclass
public abstract class AbstractEntity implements Identifiable<Integer> {
private Integer id;
private String name;
private String description;
public AbstractEntity() {
}
}
My Entity:
public class Car extends AbstractEntity {
public Car() {
}
}
I have no problems in showing the value to the user.
I have problems in validation and hyperlink in Eclipse:
<h:outputText value="#{carBean.model.name}" />
Facelet validator cannot validate name of model. It yellow underlines name. Also, I cannot Ctrl + click to activate hyperlink on name.
I saw on another developer's eclipse that both of my problems were not issues at all. I compared all the tools installed in both Eclipses and could not find anything relevant.
My question: what tools do I have to install or what settings/adjustments am I missing?
Please note: I do not want to disable the validator and I want to be able to hyperlink fields in facelet so that I will access the field using Ctrl + click.
Thank you.
I've two entities Person, Employee and Employee1. I want to implement entities inheritance in Spring Data MongoDB. Like in Spring Data JPA, what are the equivalent annotations for #Inheritance and #PrimaryKeyJoinColumn in Spring Data MongoDB. Right now, I've implemented something like this:
interface Person {
String getId();
void setId(String id);
String getName();
void getName(String name);
}
#Document(collection = "person")
class PersonImpl implements Person {
#Id
String id;
// Getters and setters
// Constructors, equals, hashcode and toString methods
}
interface Employee extends Person {
int getNumberOfDependents();
void getNumberOfDependents(int numberOfDependents);
}
#Document(collection = "employee")
class EmployeeImpl extends PersonImpl implements Employee {
// Getters and setters
// Constructors, equals, hashcode and toString methods
}
interface Employee1 extends Person {
int getNumberOfDependents();
void getNumberOfDependents(int numberOfDependents);
}
#Document(collection = "employee1")
class Employee1Impl extends PersonImpl implements Employee1 {
// Getters and setters
// Constructors, equals, hashcode and toString methods
}
Repository structure:
public interface PersonRepository extends MongoRepository<Person, String> {
}
public interface EmployeeRepository extends MongoRepository<Employee, String> {
}
public interface Employee1Repository extends MongoRepository<Employee1, String> {
}
I'm saving the Person object first and then taking the ID of it and creating an Employee object with the same ID and saving it. This creates new object and hence I'm losing all the Person object stuff.
I also feel that I've to get the NoRepositoryBean implemented also.
I'm confused. Please help.
Here is one approach:
#Document(collection = "person")
class Person {
#Id
String id;
// Getters and setters
// Constructors, equals, hashcode and toString methods
}
Note that the collection field refers to "person" and not to "employee"
#Document(collection = "person")
class Employee extends Person {
String jobTitle;
// Getters and setters
// Constructors, equals, hashcode and toString methods
}
In this method you do not need to create a repository for each derived class
#Repository
public interface PersonRepository extends MongoRepository<Person, String> {}
Code example:
#Autowired
private PersonRepository personRepo;
public void test() {
Employee employee = new Employee("1", "teacher")
personRepo.save(employee)
Optional<Person> optionalPerson = personRepo.findById("1");
Employee employeeFromDb;
if (optionalPerson.isPresent()) {
employeeFromDb = (Employee)optionalPerson.get()
}
else {
// could not find in db
}
}
if you want to find all employees you should have a methode on MongoRepository
called
List<Employee> findAll();
Is there a way to pass the enclosed object reference as a parameter to the mapping method?
public class Car {
public int id;
public Person driver;
}
public class Person {
public int carId;
}
I need a reference to the enclosing car object when mapping the person object in the personToPersonDtoAfterMapping custom method.
#Mapper
public abstract class CarMapper {
public abstract CarDto carToCarDto(Car car);
public abstract PersonDto personToPersonDto(Person person);
#AfterMapping
protected void personToPersonDtoAfterMapping(Person person, #MappingTarget PersonDto dto, Car enclosedCar) {
dto.setCarId(enclosedCar.getId())
}
}
Simply use #Context annotation. Did you try?
#Mapper
public abstract class CarMapper {
public abstract CarDto carToCarDto(Car car);
public abstract PersonDto personToPersonDto(Person person, #Context Car enclosedCar);
#AfterMapping
protected void personToPersonDtoAfterMapping(Person person, #MappingTarget PersonDto dto, #Context Car enclosedCar) {
dto.setCarId(enclosedCar.getId())
}
}
I am using spring-data for mongodb with querydsl.
I have a repository
public interface DocumentRepository extends MongoRepository<Document, String> ,QueryDslPredicateExecutor<Document> {}
and an entity
#QueryEntity
public class Document {
private String id;
private String name;
private String description;
private boolean locked;
private String message;
}
I need to load a list of documents with id and name informations.
So only id and name should be loaded and set in my entity.
I think query projection is the right word for it.
Is this supported?
In addition I need to implement some lazy loading logic.
Is there anything like "skip" and "limit" features in a repository?
There's quite a few aspects to this, as it is - unfortunately - not a single question but multiple ones.
For the projection you can simply use the fields attribute of the #Query annotation:
interface DocumentRepository extends MongoRepository<Document, String>, QuerydslPredicateExecutor<Document> {
#Query(value = "{}", fields = "{ 'id' : 1, 'name' : 1 }")
List<Document> findDocumentsProjected();
}
You can combine this with the query derivation mechanism (by not setting query), with pagination (see below) and even a dedicated projection type in the return clause (e.g. a DocumentExcerpt with only id and name fields).
Pagination is fully supported on the repository abstraction. You already get findAll(Pageable) and a Querydsl specific version of the method by extending the base interfaces. You can also use the pagination API in finder methods adding a Pageable as parameter and returning a Page
Page<Document> findByDescriptionLike(String description, Pageable pageable)
See more on that in the reference documentation.
Projection
For all I know projections are not supported by the default Spring Data repositories. If you want to make sure only the projection is sent from the DB to your application (e.g. for performance reasons) you will have to implement the corresponding query yourself. Adding custom methods to extensions of the standard repo should not be too much effort.
If you just want to hide the content of certain fields from some client calling your application, you would typically use another set of entity objects with a suitable mapping in between. Using the same POJO for different levels of detail is always confusing as you will not know if a field is actually null or if the value was just suppressed in a certain context.
Pagination
I am currently not able to test any code, but according to the documentation of QueryDslPredicateExecutor the method findAll(predicate, pageable) should be what you want:
it returns a Page object that is a regular Iterable for your Document
you have to pass it a Pageable for which you can e.g. use a PageRequest; initializing it for known values of skip and limit should be trivial
I also found this approach for JPA
Spring Data JPA and Querydsl to fetch subset of columns using bean/constructor projection
I am currently trying to implement this for MongoDB.
According to the Answer of this -> Question <- I implemeted following solution.
Entity
#QueryEntity
public class Document extends AbstractObject {
}
Custom QuerydslMongoRepository
public interface CustomQuerydslMongoRepository<T extends AbstractObject,ID extends Serializable> extends MongoRepository<T, ID> ,QueryDslPredicateExecutor<T>{
Page<T> findAll(Predicate predicate, Pageable pageable,Path... paths);
Page<T> findAll(Predicate predicate, Pageable pageable,List<Path> projections);
}
Custom QuerydslMongoRepository Implementation
public class CustomQuerydslMongoRepositoryImpl<T extends AbstractObject,ID extends Serializable> extends QueryDslMongoRepository<T,ID> implements CustomQuerydslMongoRepository<T,ID> {
//All instance variables are available in super, but they are private
private static final EntityPathResolver DEFAULT_ENTITY_PATH_RESOLVER = SimpleEntityPathResolver.INSTANCE;
private final EntityPath<T> path;
private final PathBuilder<T> pathBuilder;
private final MongoOperations mongoOperations;
public CustomQuerydslMongoRepositoryImpl(MongoEntityInformation<T, ID> entityInformation, MongoOperations mongoOperations) {
this(entityInformation, mongoOperations,DEFAULT_ENTITY_PATH_RESOLVER);
}
public CustomQuerydslMongoRepositoryImpl(MongoEntityInformation<T, ID> entityInformation, MongoOperations mongoOperations, EntityPathResolver resolver) {
super(entityInformation, mongoOperations, resolver);
this.path=resolver.createPath(entityInformation.getJavaType());
this.pathBuilder = new PathBuilder<T>(path.getType(), path.getMetadata());
this.mongoOperations=mongoOperations;
}
#Override
public Page<T> findAll( Predicate predicate, Pageable pageable,Path... paths) {
Class<T> domainType = getEntityInformation().getJavaType();
MongodbQuery<T> query = new SpringDataMongodbQuery<T>(mongoOperations, domainType);
long total = query.count();
List<T> content = total > pageable.getOffset() ? query.where(predicate).list(paths) : Collections.<T>emptyList();
return new PageImpl<T>(content, pageable, total);
}
#Override
public Page<T> findAll(Predicate predicate, Pageable pageable, List<Path> projections) {
Class<T> domainType = getEntityInformation().getJavaType();
MongodbQuery<T> query = new SpringDataMongodbQuery<T>(mongoOperations, domainType);
long total = query.count();
List<T> content = total > pageable.getOffset() ? query.where(predicate).list(projections.toArray(new Path[0])) : Collections.<T>emptyList();
return new PageImpl<T>(content, pageable, total);
}
}
Custom Repository Factory
public class CustomQueryDslMongodbRepositoryFactoryBean<R extends QueryDslMongoRepository<T, I>, T, I extends Serializable> extends MongoRepositoryFactoryBean<R, T, I> {
#Override
protected RepositoryFactorySupport getFactoryInstance(MongoOperations operations) {
return new CustomQueryDslMongodbRepositoryFactory<T,I>(operations);
}
public static class CustomQueryDslMongodbRepositoryFactory<T, I extends Serializable> extends MongoRepositoryFactory {
private MongoOperations operations;
public CustomQueryDslMongodbRepositoryFactory(MongoOperations mongoOperations) {
super(mongoOperations);
this.operations = mongoOperations;
}
#SuppressWarnings({ "rawtypes", "unchecked" })
protected Object getTargetRepository(RepositoryMetadata metadata) {
return new CustomQuerydslMongoRepositoryImpl(getEntityInformation(metadata.getDomainType()), operations);
}
protected Class<?> getRepositoryBaseClass(RepositoryMetadata metadata) {
return CustomQuerydslMongoRepository.class;
}
}
}
Entity Repository
public interface DocumentRepository extends CustomQuerydslMongoRepository<Document, String>{
}
Usage in Service
#Autowired
DocumentRepository repository;
public List<Document> getAllDocumentsForListing(){
return repository.findAll( QDocument.document.id.isNotEmpty().and(QDocument.document.version.isNotNull()), new PageRequest(0, 10),QDocument.document.name,QDocument.document.version).getContent();
}
I am using the QueryDslPredicateExecutor from Spring Data JPA project, and I am facing the need to eager fetch a lazy relation. I know that I can use a native JPA-QL query in the Repository interface, or even used the JPAQLQuery from Query DSL, but I was intrigued if this is even possible in order to facilitate building queries for future needs.
I had a similar problem where I had to fetch join a Collection while using Predicates and QueryDslPredicateExecutor.
What I did was to create a custom repository implementation to add a method that allowed me to define the entities that should be fetched.
Don't be daunted by the amount of code in here, it's actually very simple and you will need to do very few changes to use it on your application
This is the interface of the custom repository
#NoRepositoryBean
public interface JoinFetchCapableRepository<T, ID extends Serializable> extends JpaRepository<T, ID>, QueryDslPredicateExecutor<T> {
Page<T> findAll(Predicate predicate, Pageable pageable, JoinDescriptor... joinDescriptors);
}
JoinDescriptor
public class JoinDescriptor {
public final EntityPath path;
public final JoinType type;
private JoinDescriptor(EntityPath path, JoinType type) {
this.path = path;
this.type = type;
}
public static JoinDescriptor innerJoin(EntityPath path) {
return new JoinDescriptor(path, JoinType.INNERJOIN);
}
public static JoinDescriptor join(EntityPath path) {
return new JoinDescriptor(path, JoinType.JOIN);
}
public static JoinDescriptor leftJoin(EntityPath path) {
return new JoinDescriptor(path, JoinType.LEFTJOIN);
}
public static JoinDescriptor rightJoin(EntityPath path) {
return new JoinDescriptor(path, JoinType.RIGHTJOIN);
}
public static JoinDescriptor fullJoin(EntityPath path) {
return new JoinDescriptor(path, JoinType.FULLJOIN);
}
}
Implementation of the custom repository
public class JoinFetchCapableRepositoryImpl <T, ID extends Serializable> extends QueryDslJpaRepository<T, ID> implements JoinFetchCapableRepository<T, ID> {
private static final EntityPathResolver DEFAULT_ENTITY_PATH_RESOLVER = SimpleEntityPathResolver.INSTANCE;
private final EntityPath<T> path;
private final PathBuilder<T> builder;
private final Querydsl querydsl;
public JoinFetchCapableRepositoryImpl(JpaEntityInformation<T, ID> entityInformation, EntityManager entityManager) {
this(entityInformation, entityManager, DEFAULT_ENTITY_PATH_RESOLVER);
}
public JoinFetchCapableRepositoryImpl(JpaEntityInformation<T, ID> entityInformation, EntityManager entityManager, EntityPathResolver resolver) {
super(entityInformation, entityManager, resolver);
this.path = resolver.createPath(entityInformation.getJavaType());
this.builder = new PathBuilder<>(path.getType(), path.getMetadata());
this.querydsl = new Querydsl(entityManager, builder);
}
#Override
public Page<T> findAll(Predicate predicate, Pageable pageable, JoinDescriptor... joinDescriptors) {
JPQLQuery countQuery = createQuery(predicate);
JPQLQuery query = querydsl.applyPagination(pageable, createFetchQuery(predicate, joinDescriptors));
Long total = countQuery.count();
List<T> content = total > pageable.getOffset() ? query.list(path) : Collections.<T> emptyList();
return new PageImpl<>(content, pageable, total);
}
protected JPQLQuery createFetchQuery(Predicate predicate, JoinDescriptor... joinDescriptors) {
JPQLQuery query = querydsl.createQuery(path);
for(JoinDescriptor joinDescriptor: joinDescriptors)
join(joinDescriptor, query);
return query.where(predicate);
}
private JPQLQuery join(JoinDescriptor joinDescriptor, JPQLQuery query) {
switch(joinDescriptor.type) {
case DEFAULT:
throw new IllegalArgumentException("cross join not supported");
case INNERJOIN:
query.innerJoin(joinDescriptor.path);
break;
case JOIN:
query.join(joinDescriptor.path);
break;
case LEFTJOIN:
query.leftJoin(joinDescriptor.path);
break;
case RIGHTJOIN:
query.rightJoin(joinDescriptor.path);
break;
case FULLJOIN:
query.fullJoin(joinDescriptor.path);
break;
}
return query.fetch();
}
}
Factory to create the custom repositories, replacing the default QueryDslJpaRepository
public class JoinFetchCapableQueryDslJpaRepositoryFactoryBean<R extends JpaRepository<T, I>, T, I extends Serializable>
extends JpaRepositoryFactoryBean<R, T, I> {
protected RepositoryFactorySupport createRepositoryFactory(EntityManager entityManager) {
return new JoinFetchCapableQueryDslJpaRepositoryFactory(entityManager);
}
private static class JoinFetchCapableQueryDslJpaRepositoryFactory<T, I extends Serializable> extends JpaRepositoryFactory {
private EntityManager entityManager;
public JoinFetchCapableQueryDslJpaRepositoryFactory(EntityManager entityManager) {
super(entityManager);
this.entityManager = entityManager;
}
protected Object getTargetRepository(RepositoryMetadata metadata) {
return new JoinFetchCapableRepositoryImpl<>(getEntityInformation(metadata.getDomainType()), entityManager);
}
protected Class<?> getRepositoryBaseClass(RepositoryMetadata metadata) {
return JoinFetchCapableRepository.class;
}
}
}
Last step is to change the jpa configuration so it uses this factory instead of the default one:
<jpa:repositories base-package="com.mycompany.repository"
entity-manager-factory-ref="entityManagerFactory"
factory-class="com.mycompany.utils.spring.data.JoinFetchCapableQueryDslJpaRepositoryFactoryBean" />
Then you can use it from your service layer like this:
public Page<ETicket> list(ETicketSearch eTicket, Pageable pageable) {
return eticketRepository.findAll(like(eTicket), pageable, JoinDescriptor.leftJoin(QETicket.eTicket.order));
}
By using JoinDescriptor you will be able to specify what you want to join based on your service needs.
I was able to do this thanks to the Murali's response here: Spring Data JPA and Querydsl to fetch subset of columns using bean/constructor projection Please take a look.
Spring data has introduced JPA Entity Graph support. Beware that is does not currently work with graphs that are traversed via EmbeddedIds.