Develop Reference

How to filter on input parameters only using Jpa Specification?

I am writing an online-store to buy coffee and tea. I use Spring-Boot (MVC), Hibernate, JPA and PostgreSQL. In the application, I will have a filter, where I will filter the search by parameters (for example, tea color, tea type, etc.). I used the Spring-Data-Jpa Specification for this. I wrote a method that works fine and does its job. When I pass all three parameters, it filters the list for me and gives out only those drinks that fit. But what if the user does not pass all the parameters in the filter. What if it filters only by the color of the tea? What to do then? Perhaps you should use if-else, but how exactly?
Drink Class:
#Inheritance(strategy = InheritanceType.JOINED)
public class Drink {
// Fields
//
private #Id
#GeneratedValue
Long id;
private String name;
private BigDecimal price;
private String about;
#Column(name = "is_deleted")
private boolean isDeleted;
// Relationships
//
#ManyToOne
#JoinColumn(name = "packaging_id")
private Packaging packaging;
#ManyToOne
#JoinColumn(name = "manufacturer_id")
private Manufacturer manufacturer;
#ManyToOne
#JoinColumn(name = "country_id")
private Countries countries;
}
Tea Class:
public class Tea extends Drink {
// Relationships
//
#ManyToOne
#JoinColumn(name = "type_id")
private TeaType teaType;
#ManyToOne
#JoinColumn(name = "color_id")
private TeaColor teaColor;
}
SPECIFICATION:
public class TeaSpecification {
public static Specification<Tea> getTeasByFilter(Long colorId, Long typeId, Long countryId) {
return (root, query, criteriaBuilder) -> {
Predicate colorPredicate = criteriaBuilder
.equal(root.get(Tea_.teaColor).get(TeaColor_.id), colorId);
Predicate typePredicate = criteriaBuilder
.equal(root.get(Tea_.teaType).get(TeaType_.id), typeId);
Predicate countryPredicate = criteriaBuilder
.equal(root.get(Tea_.countries).get(Countries_.id), countryId);
return criteriaBuilder.and(colorPredicate, typePredicate, countryPredicate);
};
}
Service:
/**
*
* #param page
* #param pageSize
* #param colorId
* #param typeId
* #param countryId
* #return filtered Coffees(DTOs)
*/
public PageDTO<DrinkDTO> findAllByFilter(int page, int pageSize, Long colorId,
Long typeId, Long countryId) {
PageRequest pageRequest = PageRequest.of(page, pageSize, Sort.by("price").ascending());
final Page<Tea> teas = teaRepository
.findAll(TeaSpecification.getTeasByFilter(colorId, typeId, countryId), pageRequest);
return new PageDTO<>(drinkMapper.drinksToDrinksDTO(teas));
}

As you said using if will do the job. So you will add each predicate if they are not null to a list.
And then just do the following:
List<Predicate> predicates = new ArrayList<>();
// here your conditionals to create/add the predicates
Predicate query = criteriaBuilder.and(predicates.toArray(new Predicate[0]));
return criteriaBuilder.and(query);

How to allow duplicates in an arrayList when using JPA?

I keep getting "java.lang.IllegalStateException: Multiple representations of the same entity" even though I have the #Id set as true and I'm using a one to many relation on my variable.
Here are the classes which I'm trying to relate to one another:
#Entity
#Table(name = "map_area")
public class MapArea extends BasicModel {
#Id
#Column(nullable = false, unique = true)
private String name;
#OneToMany(cascade = CascadeType.ALL, fetch = FetchType.LAZY)
#JoinColumn(name = "area", referencedColumnName = "name")
public List<AlternativeAreaName> alternativeNames;
public MapArea() {}
public MapArea(String name) {
this.name = name;
this.alternativeNames = new ArrayList<>();
}
}
#Entity
#Table(name = "alternative_area_name")
public class AlternativeAreaName implements Serializable {
#Id
#Column(nullable = false, unique = false)
private String area;
#Column(nullable = true)
private String alternativeName;
public AlternativeAreaName(){}
public AlternativeAreaName(String area, String alternativeName) {
this.area = area;
this.alternativeName = alternativeName;
}
}
I want to have JPA create another table that relates to this one simple based on the name variable but whenever I try to add to the list and save to the DB I get
java.lang.IllegalStateException: Multiple representations of the same entity
MapArea mapArea = new MapArea("example");
AlternativeAreaName altAreaName1 = new AlternativeAreaName("example", "alt example");
AlternativeAreaName altAreaName2 = new AlternativeAreaName("example", "alt example2");
mapArea.alternativeNames.add(altAreaName2);
mapAreaRepository.save(mapArea);

You have used the private String area field as the primary key for entity AlternativeAreaName. So when you are trying to add
AlternativeAreaName altAreaName1 = new AlternativeAreaName("example", "alt example");
AlternativeAreaName altAreaName2 = new AlternativeAreaName("example", "alt example2");
Both of them have the same primary key. So it is throwing the above exception.
To generate the primary key for JPA entity, please check
https://www.objectdb.com/java/jpa/entity/id
https://docs.oracle.com/cd/E16439_01/doc.1013/e13981/cmp30cfg001.htm

Hibernate Envers is not able to "locate getter method for property" for Embeddable table

I have a class with #Audit annotation as below
#Entity
#Audited(withModifiedFlag=true)
#Table(name = "PERIODICITY")
public class Periodicity implements java.io.Serializable {
private PeriodicityId id;
private String frequency;
#EmbeddedId
#AttributeOverrides({
#AttributeOverride(name = "instrumentId", column = #Column(name = "INSTRUMENT_ID", nullable = false, precision = 22, scale = 0)),
#AttributeOverride(name = "legType", column = #Column(name = "LEG_TYPE", nullable = false, precision = 38, scale = 0))})
public PeriodicityId getId() {
return this.id;
}
public void setId(PeriodicityId id) {
this.id = id;
}
#Column(name = "FREQUENCY", nullable = false, length = 20)
public String getFrequency() {
return this.frequency;
}
}
And the Embedded class is as follows
#Embeddable
public class PeriodicityId implements java.io.Serializable {
private Long instrumentId;
private Long legType;
#Column(name = "INSTRUMENT_ID", nullable = false, precision = 22, scale = 0)
public Long getInstrumentId() {
return this.instrumentId;
}
public void setInstrumentId(Long instrumentId) {
this.instrumentId = instrumentId;
}
#Column(name = "LEG_TYPE", nullable = false, precision = 38, scale = 0)
public Long getLegType() {
return this.legType;
}
}
And through audit reader I'm trying to find Audit at particular revision as follows
Session session = HibernateUtil.currentSession();
AuditReader reader = AuditReaderFactory.get(session);
Periodicity periodicity = reader.find( Periodicity.class, instrumentId, revision_Id);
But its giving exception like
org.hibernate.PropertyNotFoundException: Could not locate getter method for property [java.lang.Long#instrumentId]
at org.hibernate.internal.util.ReflectHelper.findGetterMethod(ReflectHelper.java:408)
at org.hibernate.property.access.internal.PropertyAccessBasicImpl.<init>(PropertyAccessBasicImpl.java:41)
at org.hibernate.property.access.internal.PropertyAccessStrategyBasicImpl.buildPropertyAccess(PropertyAccessStrategyBasicImpl.java:27)
at org.hibernate.envers.internal.tools.ReflectionTools.getGetter(ReflectionTools.java:53)
Please Help how to access property of Embeddable class..

I'll add what I mentioned in HipChat here for posterity sake.
What you are attemping to do is to use the AuditReader#find method by specifying a specific value of your composite-id class. The method signature that you're using expects the actual embeddable class and not a specific attribute type the embeddable contains.
The proper usage of AuditReader#find would be like:
// define your embeddable class attributes
final PeriodicityId id = new PeriodicityId();
id.setInstrumentId( instrumentId );
// lookup revision 1
final Number revisionId = 1;
// query
final AuditReader auditReader = AuditReaderFactory.get( session );
auditReader.find( Periodicity.class, id, revisionId );
Whlie this avoids the exception you encountered, this won't give you the expected results because the embeddable predicates will assume you're interested in Perodicity instances where the legType attribute is null which is not your goal.
The only way you can accomplish the goal of your task then is to use Envers adhoc query features where you specify the precise predicates to target the results you're interested in.
final AuditReader auditReader = AuditReaderFactory.get( session );
List results = auditReader.createQuery()
.forRevisionsOfEntity( Periodicity.class, true, false )
// add the revision number predicate
.add( AuditEntity.revisionNumber().eq( revisionId ) )
// add the instrument predicate
.add( AuditEntity.property( "id.instrumentId" ).eq( instrumentId ) )
.getResultList();
Hope that helps.

How To Query Relationship Between Three Entities in Spring JPA

I am working on my senior project and my group's client has required that we use Spring Boot, which none of us are familiar with. Right now I'm working on making a paginated, sortable list that will show a logged in user the visits that are associated with their user id. Our models are as follows:
#Entity
#Table(name="users")
public class User {
#Id
#GeneratedValue(strategy = GenerationType.AUTO)
#JsonView(View.User.class)
private long id;
#Column(name = "full_name")
#NotNull
#JsonView(View.User.class)
private String fullName;
#Column(name = "is_manager")
#NotNull
private boolean isManager;
#ManyToMany(cascade = CascadeType.ALL, mappedBy = "users")
private Set<Visit> visits;
#OneToMany(cascade=CascadeType.ALL, mappedBy="user")
private Set<VisitEntry> visitEntries;
-
#Entity
#Table(name="visits")
public class Visit implements Iterable<VisitEntry> {
static final public String INSPECTION_TYPE_FULL = "Full Inspection";
#Id
#GeneratedValue(strategy = GenerationType.AUTO)
#JsonView(View.Visit.class)
private long id;
#Column(name = "visit_number")
#NotNull
#JsonView(View.Visit.class)
private int visitNumber;
#ManyToOne(cascade=CascadeType.ALL)
#NotNull
#JsonView(View.Visit.class)
private Provider provider;
#ManyToOne(cascade=CascadeType.ALL)
private User leader;
#ManyToMany(cascade = {CascadeType.ALL})
#JoinTable(name="users_visits",
joinColumns={#JoinColumn(name="VISIT_ID")},
inverseJoinColumns = #JoinColumn(name = "USER_ID")
)
private Set<User> users;
#OneToMany(cascade=CascadeType.ALL, mappedBy="visit")
#JsonView(View.Visit.class)
#JsonManagedReference
private List<VisitEntry> visitEntries = new ArrayList<>();
#Column(name = "open")
#NotNull
private boolean open;
-
#Entity
#Table(name="visit_entries")
public class VisitEntry {
#Id
#GeneratedValue(strategy = GenerationType.AUTO)
#JsonView(View.Visit.class)
private long id;
#Column(name = "pre_inspection")
#JsonView(View.Visit.class)
private int preInspectionPrepHours;
#ManyToOne(cascade = CascadeType.ALL)
#NotNull
#JsonBackReference
private Visit visit;
#ManyToOne(cascade=CascadeType.ALL)
#NotNull
#JsonView(View.Visit.class)
private User user;
So we have visits which have many visit entries and each visit entry has a user. What I need is to get all visits associated with a user.
Unfortunately after each reading various tutorials my teammates and I are incredibly confused and have entirely different ideas on how to do this, none of which have actually worked. Based on this question (Joining two table entities in Spring Data JPA) I created the relationship between visits and users thinking that I would then be able to use Page<Visit> findByUsers(User user, Pageable pageable); in my repository, but I always get an empty set. So now we've ended up with this ugly piece of code that works as far as paginating but does not do any sorting:
#RequestMapping(value="/visits/{pageNum}/{sort}/{direction}", method= RequestMethod.GET)
public String visits(#PathVariable int pageNum,
#PathVariable String sort,
#PathVariable String direction,
Model model,
HttpServletRequest request) {
User currentUser = getUser(request);
final int pageSize = 10;
Pageable pageable;
//get direction info from parameters and convert to Sort.Direction enum
if (direction.compareTo("asc") == 0)
pageable = new PageRequest(pageNum - 1, pageSize, Sort.Direction.ASC, sort);
else
pageable = new PageRequest(pageNum - 1, pageSize, Sort.Direction.DESC, sort);
//get pageable list of visits dependant on current user
Page<Visit> visits;
if(currentUser.isManager()) {
visits = visitRepo.findAll(pageable);
}
else {
//visits = visitRepo.findByUser_Id(currentUser, pageable);
List<VisitEntry> entries = visitEntryDao.findByUser(currentUser);
List<Visit> visitList = new ArrayList<>();
for (int x = 0; x < entries.size(); x++) {
visitList.add(entries.get(x).getVisit());
}
int offset = (pageNum - 1) * pageSize;
int offsetEnd = offset + 10;
if (offsetEnd > visitList.size())
offsetEnd = visitList.size();
List<Visit> content = visitList.subList(offset, offsetEnd);
visits = new PageImpl<Visit>(content, pageable, visitList.size());
}
edu.ewu.timetrackers.util.Page[] pages = new edu.ewu.timetrackers.util.Page[visits.getTotalPages()];
for (int i = 0; i < visits.getTotalPages(); i++) {
pages[i] = new edu.ewu.timetrackers.util.Page(i + 1, pageNum == i + 1);
}
//add visit and number of pages to model
model.addAttribute("visits", visits);
model.addAttribute("pageCount", visits.getTotalPages());
//add sorting and paging info to model
model.addAttribute("pageNum", pageNum);
model.addAttribute("sort", sort);
model.addAttribute("direction", direction);
model.addAttribute("pages", pages);
//below attributes determine previous and next buttons for pagination
if (pageNum > 1)
model.addAttribute("notFirst", pageNum - 1);
if (pageNum < visits.getTotalPages())
model.addAttribute("notLast", pageNum + 1);
return "visits";
}
Can anyone clear up the correct way to do this? We've tried asking around and not found anyone in our community that uses Spring that can help us understand what we're missing here.
Thanks!

Hibernate complex data retrieval?

I have nine related tables in my database.i have to retrieve records after filtering user request.
My Entities follows ,
Movie
#Entity
#Table(name = "movie")
public class Movie implements Serializable {
private static final long serialVersionUID = 1L;
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
#Column(name = "movie_id")
private int movieId;
#Column(name = "category_id")
private Integer categoryId;
#Column(name = "movie_title")
private String movieTitle;
#Column(name = "movie_description", columnDefinition = "TEXT")
private String movieDescription;
#Column(name = "movie_summary", columnDefinition = "TEXT")
private String movieSummary;
private Integer status;
#Column(name = "language_id")
private Integer languageId;
#Column(name = "banner_image_url")
private String bannerImageUrl;
#Column(name = "imdb_rating")
private Integer imdbRating;
#Column(name = "rotten_tomatoes_rating")
private Integer rottenTomatoesRating;
#Column(name = "user_avg_rating")
private Float userAvgRating;
#Column(name = "main_genre_id")
private Integer mainGenreId;
#Column(name = "secondary_genre_id")
private Integer secondaryGenreId;
#Column(name = "created_by_user_id")
private Integer createdByUserId;
}
Category
#Entity
#Table(name = "category")
public class FetchSubCategory implements Serializable {
private static final long serialVersionUID = 1L;
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
#Column(name = "category_id")
private Integer categoryId;
#Column(name = "category_name")
private String categoryName;
}
MovieActorMapping
#Entity
#Table(name = "movie_actor_mapping")
public class MovieActorMapping implements Serializable {
private static final long serialVersionUID = 1L;
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
#Column(name = "mapping_id")
private int mappingId;
#Column(name = "movie_id")
private Integer movieId;
#Column(name = "actor_id")
private Integer actorId;
}
MovieActors
#Entity
#Table(name = "movie_actors")
public class MovieActors implements Serializable {
private static final long serialVersionUID = 1L;
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
#Column(name = "actor_id")
private int actorId;
#Column(name = "actor_name")
private String actorName;
}
MovieGenre
#Entity
#Table(name = "movie_genre")
public class MovieGenre implements Serializable {
private static final long serialVersionUID = 1L;
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
#Column(name = "genre_id")
private int genreId;
#Column(name = "genre_name")
private String genreName;
#Column(name = "created_by_user_id")
private Integer createdByUserId;
}
MovieLanguage
#Entity
#Table(name = "movie_language")
public class MovieLanguage implements Serializable {
private static final long serialVersionUID = 1L;
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
#Column(name = "language_id")
private int languageId;
#Column(name = "language_name")
private String languageName;
#Column(name = "created_by_user_id")
private Integer createdByUserId;
#Column(name = "last_updated_user_id")
private Integer lastUpdatedUserId;
}
The user will request like below .all are optional fields ,
{
"subCategory":"New Release",
"language":"Malayalam",
"actor":"allu arjun",
"filmGenre":"'Family'"
}
According to the request i will return the movie list by checking conditions from corresponding table using subquery.
Method
public List<Movie> getFilterMovieList(FilterMovieRequest filterMovieRequest) throws SQLException, ClassNotFoundException, IOException {
List<Movie> movies = null;
try {
String subCategory = filterMovieRequest.getSubCategory();
String language = filterMovieRequest.getLanguage();
String actor = filterMovieRequest.getActor();
String filmGenre = filterMovieRequest.getFilmGenre();
String contained = "where";
String sql = "from Movie as M ";
if (actor.length() > 1) {
sql += contained + " movieId in(select movieId from MovieActorMapping where actorId in(select actorId from MovieActors where actorName='" + actor + "')) ";
contained = "and";
}
if (subCategory.length() > 1) {
sql += contained + " M.categoryId=(select categoryId from FetchSubCategory where categoryName='" + subCategory + "') ";
contained = "and";
}
if (language.length() > 1) {
sql += contained + " M.languageId=(select languageId from MovieLanguage where languageName='" + language + "') ";
contained = "and";
}
if (filmGenre.length() > 1) {
sql += contained + " (M.mainGenreId in(select genreId from MovieGenre where genreName in(" + filmGenre + ")) or M.secondaryGenreId in(select genreId from MovieGenre where genreName in(" + filmGenre + ")))";
contained = "and";
}
if (contained.equals("and")) {
Session session = sessionFactory.getCurrentSession();
Query query = session.createQuery(sql);
movies = query.list();
}
} catch (Exception e) {
e.printStackTrace();
}
return movies;
}
And it works fine.the problem is now i have to combine with the result in which theaters movies is playing and the show time also.
And my theater related tables follow,
theater_movie_mapping
theater_list
show_timings
you can see in column movie_id in theater_movie_mapping which related to my base table movie. using that we can fetch theater_id and show_id for fetch the theaters and show timing..note that i have a movie list early fetched after checking above conditions.How can i combine theaters from theater_list and show times from show_timings ? being an android developer it seems complex for me.Am totally stucked. Any help will be appreciated.Am using Spring restful webservice.
Now i have getting the result in following format,
[
{
"movieId": 8,
"categoryId": 14,
"movieTitle": "Kanyaka Talkies",
"movieDescription": "CRITICS 3 out of 5 (Good) 3 out of 5 (Good) The composite emotional weather that the film sports makes it maddening and nurturing at once, rendering it an almost enigmatic feel. And it is this ethereal complexity that 'Kanyaka Talkies' inherently has, that makes the film singular. ",
"movieSummary": "The concurrence of the three key characters in 'Kanyaka Talkies' isn't of the traditionalist kind; rather, by throwing the three of them together, the film does achieve the ostensibly improbable feat of placing the unlikeliest of players collectively on board, with their fates irrevocably intertwined with each other. ",
"status": 1,
"languageId": 1,
"bannerImageUrl": "0",
"imdbRating": 1,
"rottenTomatoesRating": 3,
"userAvgRating": 2,
"mainGenreId": 1,
"secondaryGenreId": 2,
"createdByUserId": 16
},
{
"movieId": 9,
"categoryId": 14,
"movieTitle": "Wonderful Journey",
"movieDescription": "Wonderful Journey' is one of the most misdirecting titles as yet for a film this year. Anything but wonderful, this is an absolute cinematic misadventure that will have you pulling out your hair strands in no time. ",
"movieSummary": "Some things in life simply cannot be averted, they say. I do agree, what with the late night show of 'Wonderful Journey' getting cancelled yesterday night and me courageously venturing out for it yet again today noon, only to embark on one of the most horrendous journeys I have ever gone for in my entire life. ",
"status": 1,
"languageId": 1,
"bannerImageUrl": "0",
"imdbRating": 1,
"rottenTomatoesRating": 3,
"userAvgRating": 2,
"mainGenreId": 1,
"secondaryGenreId": 1,
"createdByUserId": 16
},
{
"movieId": 10,
"categoryId": 14,
"movieTitle": "Oru New Generation Pani",
"movieDescription": "Very occasionally does a movie come along that almost makes you vow to stay off the screens for a few weeks, and this year, the one has finally arrived. I'd gladly go ahead with a no-star rating for this one, had it not been for a technical glitch that prevents me from doing so! ",
"movieSummary": "'Oru New Generation Pani' is an atrocity that shocks you with its attempt to spin out a story line that will have you banging you head against the rails. Inauthentic to the core, the film tells a story that will have an insomniac snoring away in no time. ",
"status": 1,
"languageId": 1,
"bannerImageUrl": "0",
"imdbRating": 1,
"rottenTomatoesRating": 3,
"userAvgRating": 2,
"mainGenreId": 1,
"secondaryGenreId": 2,
"createdByUserId": 16
}
]
I have to add the theaters and show time too in every json object ie ,every movie..

Assume theater_movie_mapping is mapped to Class TheaterMovie which contains Movie movie in it
ArrayList<TheaterMovie> list = new ArrayList<TheaterMovie>();
for(int i = 0 ; i < movies.size() ; i++){
list.addAll((ArrayList<TheaterMovie>)createQuery("From TheaterMovie tm where tm.movies = :mo").setParameter("mo",movies.get(i)).getList());
}
Now assume show_timings is mapped to Class ShowTiming which contains Theater theater in it
ArrayList<ShowTiming> showTimeList = new ArrayList<ShowTiming>();
for(int i = 0 ; i < list.size() ; i++){
showTimeList = (ArrayList<ShowTiming>)createQuery("From ShowTiming st where st.theater = :th").setParameter("th",list.get(i).getTheater()).getList();
}
I hope this works well for you