I have an "interesting" structure for entities and I'm stuck trying to clone them. I basically have one super-parent that I'm cloning. Let's call this class Document. A document has at least one Function and one Component. Now this part isn't an issue, these are #OneToMany and #ManyToOne and I can clone them just fine. But now there is a third class that belongs to both Function and Component - let's call it an Interaction. By design this is part of both the Function and the Component as it described something that both do when interacting.
Now in a normal flow there would be an order for creation, where a Document is created first, then at least one Component and Function is created automatically. After that Interactions can be created. You can imagine this like a matrix, where an Interaction described how one Component interacts with one Function. Generally speaking Component and Function are not related and can exist independently, though at least one of each will always exist so that the matrix exists.
Now the issue is cloning an entire document. When cloning all the nested entities must be cloned and keep their relations. However IDs are not known at clone time (as they must be unset or new entities created) so I'm not sure how to prevent duplicates here.
How would one clone this entire Document and it's sub-relations with new IDs and keep all the relations intact? I know this is easy if all the relations are in a "linear" structure, but multiple parents appear to be difficult.
Here is a diagram for clarity:
Document.java
#Table(name = "document")
#Entity
public class Document {
#Id
#GeneratedValue(strategy = GenerationType.AUTO)
private Integer id;
#OneToMany(mappedBy = "document", cascade = CascadeType.ALL)
private List<Component> components = new ArrayList<>();
#OneToMany(mappedBy = "document", cascade = CascadeType.ALL)
private List<Function> functions = new ArrayList<>();
}
Component.java
#Table(name = "component")
#Entity
public class Component {
#Id
#GeneratedValue(strategy = GenerationType.AUTO)
private Integer id;
#ManyToOne
private Document document;
#OneToMany(mappedBy = "component", cascade = CascadeType.ALL)
private List<Interaction> interactions;
}
Function.java
#Table(name = "function")
#Entity
public class Function {
#Id
#GeneratedValue(strategy = GenerationType.AUTO)
private Integer id;
#ManyToOne
private Document document;
#OneToMany(mappedBy = "function", cascade = CascadeType.ALL)
private List<Interaction> interactions;
}
Interaction.java
#Table(name = "interaction")
#Entity
public class Interaction {
#Id
#GeneratedValue(strategy = GenerationType.AUTO)
private Integer id;
#ManyToOne
private Function function;
#ManyToOne
private Component component;
}
For copying a graph one usually has to build an identity map from source to target and query that before doing a copy. Something like this:
interface CustomClonable {
Object clone(Map<Object, Object> mapping);
}
public static <T extends CustomClonable> T clone(T original, Map<Object, Object> mapping) {
Object copy = mapping.get(original);
if (copy == null) {
copy = original.clone(mapping);
mapping.put(original, copy);
}
return (T) copy;
}
All your type implement that interface and clone themselves, invoking the static clone method for nested objects.
Related
I think I have a bad setup for my hibernate database. I have Citizen entities who have one to many relationships with WeeklyCare entities. Below is the relevant code.
Citizen:
#Entity
#Table(name = "citizens")
public class Citizen {
#Id
#Size(max = 10, min = 10, message = "CPR must be exactly 10 characters")
private String cpr;
#OneToMany()
#JoinColumn(name = "cpr")
private List<WeeklyCare> weeklyCare;
}
WeeklyCare:
#Entity
public class WeeklyCare {
#EmbeddedId
private WeeklyCareIdentifier weeklyCareIdentifier;
}
WeeklyCareIdentifier:
#Embeddable
public class WeeklyCareIdentifier implements Serializable {
#NotNull
#Size(max = 10, min = 10, message = "CPR must tbe exactly 10 characters")
private String cpr;
#NotNull
private Integer week;
#NotNull
private Integer year;
}
I have some problems when I want to save data to the database:
I can't save WeeklyCare first, because it requires a Citizen.
When I send the citizens to my backend, the objects contain a list of WeeklyCare. When I try to save the citizens, it gives me this error: Unable to find Application.Models.WeeklyCare with id Application.Models.WeeklyCareIdentifier#b23ef67b
I can solve the problem by clearing the list of WeeklyCare on the Citizen before saving it, and then saving the list of WeeklyCare after, but that feels like a terrible way to do it.
I guess I want hibernate to ignore the list of WeeklyCare when it saves a Citizen, but acknowledge it when it fetches a Citizen. Is this possible? Or is there an even better way to do it? Thanks.
I can't save WeeklyCare first, because it requires a Citizen.
You have the "cpr" identifier used in two entities:
it's the primary Id for Citizen
it's part of the composite Id for WeeklyCare
You could, theoretically speaking, create a list of WeeklyCare (not with the way it is modeled now though) and later update the associations of each WeeklyCare to Citizen.
When I send the citizens to my backend, the objects contain a list of WeeklyCare. When I try to save the citizens, it gives me this
error: Unable to find Application.Models.WeeklyCare with id
Application.Models.WeeklyCareIdentifier#b23ef67b
The best way to map One-To-Many association is bidirectional. This will also save you from some unnecessary queries Hibernate is generating when using #OneToMany with #JoinColumn only.
1) Remove cpr from WeeklyCareIdentifier class (and probably rename the class).
#Embeddable
public class WeeklyCareIdentifier implements Serializable {
#NotNull
private Integer week;
#NotNull
private Integer year;
//constructors, getters, setters
}
2) Remove the composite #EmbeddedId in favor of Long id field:
#Entity
public class WeeklyCare {
#Id
#GeneratedValue
private Long id;
#Embedded
private WeeklyCareIdentifier weeklyCareIdentifier;
//constructors, getters, setters
}
3) Move to bidirectional mapping:
#Entity
#Table(name = "citizens")
public class Citizen {
#Id
#Size(max = 10, min = 10, message = "CPR must be exactly 10 characters")
private String cpr;
#OneToMany(
mappedBy = "citizen",
cascade = CascadeType.ALL, //cascade all operations to children
orphanRemoval = true //remove orphaned WeeklyCare if they don't have associated Citizen
)
private List<WeeklyCare> weeklyCares = new ArrayList<>(); //init collections to avoid nulls
//constructors, getters, setters
//add utility methods to manipulate the relationship
public void addWeeklyCare(WeeklyCare weeklyCare) {
weeklyCares.add(weeklyCare);
weeklyCare.setCitizen(this);
}
public void removeWeeklyCare(WeeklyCare weeklyCare) {
weeklyCares.remove(weeklyCare);
weeklyCare.setCitizen(null);
}
}
and:
#Entity
public class WeeklyCare {
#Id
#GeneratedValue
private Long id;
//having reference to the citizen entity from WeeklyCare
#ManyToOne(fetch = FetchType.LAZY)
#JoinColumn(name = "citizen_cpr")
private Citizen citizen;
#Embedded
private WeeklyCareIdentifier weeklyCareIdentifier;
//constructors, getters, setters
}
I would also recommend to use Long ids for the entities, even if the cpr is unique and so on. Convert the cpr to a normal column and introduce a DB generated ID column which you use in to join with in your internal domain and treat the cpr as a pure user-facing data column.
I have two entities mapped to one another using the oneToMany annotation. One entity is bookedBus and the second is drivers The drivers entity would already have a row inserted into that would later become a foreign reference (FK) to bookedBus entity(PK). Below are the two entities, setters and getter have been skipped for brevity.
First entity
#Entity
#Table(name = "bookedBuses")
public class BookedBuses implements Serializable {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;
#ManyToOne(fetch = FetchType.LAZY, cascade = CascadeType.ALL)
#JoinColumn(name = "driver_id")
private Drivers driver;
}
Second entity
#Entity
public class Drivers implements Serializable {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;
#OneToMany(fetch = FetchType.LAZY, cascade = CascadeType.ALL, orphanRemoval = true, mappedBy = "driver")
private List<BookedBuses> bookedBus;
}
Now When I try to save to the booked bus entity it throws the following exception
org.springframework.dao.InvalidDataAccessApiUsageException: detached entity passed to persist: com.bus.api.entity.Drivers; nested exception is org.hibernate.PersistentObjectException: detached entity passed to persist: com.bus.api.entity.Drivers
Below is how I tried saving to the bookedBus entity
BookedBuses bookedRecord = new BookedBuses();
bookedRecord.setBookedSeats(1);
bookedRecord.setBookedBusState(BookedBusState.LOADING);
bookedRecord.setBus(busService.getBusByPlateNumber(booking.getPlateNumber()));
bookedRecord.setRoute(booking.getRoute());
infoLogger.info("GETTING DRIVER ID ======= " + booking.getDriver().getId());
Drivers drivers = new Drivers(booking.getDriver().getId());
List<BookedBuses> d_bu = new ArrayList<>();
drivers.setBooked(d_bu);
drivers.addBooked(bookedRecord);
bookedRecord.setDriver(drivers);
bookedBusService.save(bookedRecord);
My BookBusService Save Method as requested
#Autowired
private BookedBusRepository bookedBusRepo;
public boolean save(BookedBuses bookedRecord) {
try {
bookedBusRepo.save(bookedRecord);
return true;
} catch (DataIntegrityViolationException ex) {
System.out.println(ex);
AppConfig.LOGGER.error(ex);
return false;
// Log error message
}
}
1st you have some mix up in naming: you have Driver & Drivers. Like this:
private Drivers driver;
Also selecting variable names like this:
BookedBuses bookedRecord = new BookedBuses();
will cause a lot of confusion. Do not mix plural & singular between types and preferably also do not introduce names that might not be easily associated like record. Also this:
private List<BookedBuses> bookedBus;
which should rather be like:
private List<BookedBus> bookedBuses;
(and would alsoi require change to your class name BookedBuses -> BookedBus)
Anyway the actual problem seems to lie here:
Drivers drivers = new Drivers(booking.getDriver().getId());
You need to fetch existing entity by id with a help of repository instead of creating a new one with id of existing. So something like:
Drivers drivers = driverRepo.findOne(booking.getDriver().getId()); // or findById(..)
It seems that you have a constructor (that you did not show) that enables to create a driver with id. That is not managed it is considered as detached. (You also have drivers.addBooked(bookedRecord); which you did not share but maybe it is trivial)
Note also some posts suggest to changeCascadeType.ALL to CascadeType.MERGE whether that works depends on your needs. Spring data is able to do some merging on save(..) based on entity id but not necessarily in this case.
This line
Drivers drivers = new Drivers(booking.getDriver().getId());
If you already have the driver ID available with you then there's no need to pull the driver ID again from the DB.
After removing the Cascade attribute from #OneToMany & #ManyToOne your code should work.
#Entity
#Table(name = "bookedBuses")
public class BookedBuses implements Serializable {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;
`
#ManyToOne(fetch = FetchType.LAZY)
#JoinColumn(name = "driver_id")
private Drivers driver;
}
#Entity
public class Drivers implements Serializable {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;
#OneToMany(fetch = FetchType.LAZY)
#JoinColumn(name = "driver_id")
private List<BookedBuses> bookedBus;
}
I have Parent entity Head and associated childs are Detail and Comment mapped using onetomany. I have only one DAO which is HeadDao. ProjectNumber PK in Head and FK in Detail and Comment. I'm trying to figure out how to delete the Child Comment using the projectNumber without writing the DAO for the child.
Scenario is, while updating the Head i want to first delete the existing (associated) Comments from the database (using the projectNumber) and then add the new comments which are coming in the request. Could any one help me with this.
Below are Entity classes (FYI Comment class has composite id, but i not pasted it here)
#Entity(name = "Head")
#Table(name = "HEAD")
public class Head {
#Id
#Column(name = "PRJ_NBR")
private Integer projNumber;
#JsonIgnore
#OneToMany(mappedBy = "head",cascade = CascadeType.ALL,orphanRemoval =
true,fetch = FetchType.LAZY)
private List<Detail> detailsList = new ArrayList<Detail>();
#JsonIgnore
#OneToMany(mappedBy = "head",cascade = CascadeType.ALL,orphanRemoval =
true,fetch = FetchType.LAZY)
private List<Comment> commentsList = new ArrayList<Comment>();
}
#Entity
#Table(name = "PRJ_CMT")
#JsonIgnoreProperties
public class Comment {
#Transient
private Integer projectNumber;
#JsonIgnore
#EmbeddedId
private CommentCompositeId id;
#JsonIgnore
#ManyToOne
#JoinColumn(name = "PRJ_NBR", updatable=false, insertable=false)
private Head head;
}
#Transactional
#Repository
#PersistenceContext(type = PersistenceContextType.EXTENDED)
public abstract interface HeadDao extends JpaRepository<Head,
Serializable>
{
public abstract List<Head> findByProjNumber(Integer paramInteger);
public abstract List<Head> findAll();
#SuppressWarnings("unchecked")
public abstract Head saveAndFlush(Head paramHead);
public abstract List<Head> findByCusSysId(Integer paramInteger);
public abstract Integer deleteByProjNumber(Integer projNumber);
}
While adding i'm using below code
this.headDao.saveAndFlush(head);
Solved the problem by adding cascade = CascadeType.PERSIST to the ManytoOne (comment) side (cascade all should be present on the onetomany - head).
Now when i'm adding the list of comments, its deleting the comments (for the project number) which are not present the current list and updating other comments
How about simply by replacing commentsList for existing head ?
Create setter for head.commentsList.
Replace comments with newComments = new ArrayList<Comment>() that is populated with the new comments, then head.setCommentsList(newComments).
Persist head, this.headDao.saveAndFlush(head);.
I have two entities, let's say
Person.java:
#Entity
public class Person implements Serializable {
#Id
#GeneratedValue(strategy = AUTO)
private long id;
#OneToMany(mappedBy = "personData", cascade = CascadeType.PERSIST)
private List<SkillsData> skillsData;
// ...
}
SkillsData.java
#Entity
#Table(name = "SkillsData")
public class SkillsData implements Serializable {
#Id
#GeneratedValue(strategy = AUTO)
private long id;
#JoinColumn(name = "PERSONID")
#ManyToOne(cascade = REMOVE)
private Person personData;
// ...
}
When I create a person, add a list of type SkillsData to it's skillsData field and persist it everything works with no exceptions thrown, but when I browse the database directly in the SkillsData table the field PERSONID is not populated and because of that the skills added can't be referenced to the right person.
I'm trying to fix this problem for quite some time and I'll be thankful for any help.
The problem might be in the fact that you're not setting SkillsData.personData before persisting leaving it null.
You must set it cause adding SkillsData to the Person.skillsData list is not enough since you declared this side of relationship as inverse(mappedBy attribute).
Therefore it is the SkillsData.personData non-inverse side who is responsible for establishing this relationship.
I'm trying to write a hibernate adapter for an old database schema. This schema does not have a dedicated id column, but uses about three other columns to join data.
On some tables, I need to use coalesce. This is what I came up with so far:
About the definition:
A car can have elements, assigned by the car's user or by the car's group of users.
If FORIGN_ELEMENT holds a user's name, definition will be 'u'
If FORIGN_ELEMENT holds a group's name, definition will be 'g'
This also means, one table (CAR_TO_ELEMENT) is misused to map cars to elements and cargroups to elements. I defined a superclass CarElement and subclasses CarUserElement and CarGroupElement.
state is either "active" or an uninteresting string
I set definitition and state elsewhere, we do not need to worry about this.
Use DEP_NR on the join table. If it's zero, use USR_DEP_NR. I did this with COALESCE(NULLIF()) successfully in native SQL and want to achieve the same in Hibernate with Pojos.
Okay, here we go with the code:
#Entity
#Table(name="CAR")
public class Car extends TableEntry implements Serializable {
#Id
#Column(name="DEP_NR")
private int depnr;
#Id
#Column(name="USER_NAME")
#Type(type="TrimmedString")
private String username;
#ManyToOne(fetch = FetchType.EAGER, targetEntity=CarGroup.class)
#JoinColumns(value={
#JoinColumn(name="GROUP_NAME"),
#JoinColumn(name="DEP_NR"),
#JoinColumn(name="state"),
})
private CarGroup group;
#OneToMany(fetch=FetchType.EAGER, targetEntity=CarUserElement.class, mappedBy="car")
private Set<CarUserElement> elements;
}
#Entity
#Table(name="CAR_GROUP")
public class CarGroup extends TableEntry implements Serializable {
#Id
#Column(name="DEP_NR")
private int depnr;
#Id
#Column(name="GROUP_NAME")
#Type(type="TrimmedString")
private String group;
#ManyToOne(fetch = FetchType.EAGER, targetEntity=Car.class)
#JoinColumns(value={
#JoinColumn(name="GROUP_NAME"),
#JoinColumn(name="DEP_NR"),
#JoinColumn(name="state"),
})
private Set<Car> cars;
#OneToMany(fetch=FetchType.EAGER, targetEntity=CarGroupElement.class, mappedBy="car")
private Set<CarGroupElement> elements;
}
#MappedSuperclass
public class CarElement extends TableEntry {
#Id
#ManyToOne(fetch = FetchType.EAGER, targetEntity=Element.class)
#JoinColumns(value={
#JoinColumn(name="ELEMENT_NAME"),
#JoinColumn(name="state"),
})
private Element element;
}
#Entity
#Table(name="CAR_TO_ELEMENT")
public class CarUserElement extends CarElement {
#Id
#Column(name="DEFINITION")
private char definition;
#Id
#ManyToOne(fetch = FetchType.LAZY)
#JoinColumnsOrFormulas(value = {
#JoinColumnOrFormula(formula=#JoinFormula(value="COALESCE(NULLIF(DEP_NR, 0), USR_DEP_NR)", referencedColumnName="DEP_NR")),
#JoinColumnOrFormula(column=#JoinColumn(name="FORIGN_ELEMENT", referencedColumnName="USER_NAME")),
#JoinColumnOrFormula(column=#JoinColumn(name="STATE", referencedColumnName="STATE"))
})
private Car car;
}
#Entity
#Table(name="CAR_TO_ELEMENT")
public class CarGroupElement extends CarElement {
#Id
#Column(name="DEFINITION")
private char definition;
#Id
#ManyToOne(fetch = FetchType.LAZY)
#JoinColumnsOrFormulas(value = {
#JoinColumnOrFormula(formula=#JoinFormula(value="COALESCE(NULLIF(DEP_NR, 0), USR_DEP_NR)", referencedColumnName="DEP_NR")),
#JoinColumnOrFormula(column=#JoinColumn(name="FORIGN_ELEMENT", referencedColumnName="GROUP_NAME")),
#JoinColumnOrFormula(column=#JoinColumn(name="STATE", referencedColumnName="STATE"))
})
private Car car;
}
I tried all available versions of hibernate (from 3.5.1 [first version with #JoinColumnsOrFormulas] up to 4.x.x), but I always get this error:
Exception in thread "main" java.lang.ClassCastException: org.hibernate.mapping.Formula cannot be cast to org.hibernate.mapping.Column
at org.hibernate.cfg.annotations.TableBinder.bindFk(TableBinder.java:351)
at org.hibernate.cfg.annotations.CollectionBinder.bindCollectionSecondPass(CollectionBinder.java:1338)
at org.hibernate.cfg.annotations.CollectionBinder.bindOneToManySecondPass(CollectionBinder.java:791)
at org.hibernate.cfg.annotations.CollectionBinder.bindStarToManySecondPass(CollectionBinder.java:719)
at org.hibernate.cfg.annotations.CollectionBinder$1.secondPass(CollectionBinder.java:668)
at org.hibernate.cfg.CollectionSecondPass.doSecondPass(CollectionSecondPass.java:66)
at org.hibernate.cfg.Configuration.originalSecondPassCompile(Configuration.java:1597)
at org.hibernate.cfg.Configuration.secondPassCompile(Configuration.java:1355)
at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:1737)
at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:1788)
Other hibernate users seem to have the same problem: They can't get it working with any version, see this thread and other stackoverflow questions:
https://forum.hibernate.org/viewtopic.php?f=1&t=1010559
To be more complete, here's my TrimmedString Class:
https://forum.hibernate.org/viewtopic.php?p=2191674&sid=049b85950db50a8bd145f9dac49a5f6e#p2191674
Thanks in advance!
PS: It works with joining just these three colulmns with just one DEP-NR-Column (i.e. either DEP_NR OR USR_DEP_NR using just #JoinColumns). But I need this coalesce(nullif()).
I ran into a similar problem, and it seems that the issue is that you are using a #Formula inside an #Id. Hibernate wants Ids to be insertable, and Formulas are read-only.
In my case I was able to work around the problem by making the individual columns Id properties on their own, and making the joined object a separate property. I don't know if this would work in your case since you're using two different columns in your formula, but if so your code might look something like:
#Entity
#Table(name="CAR_TO_ELEMENT")
public class CarUserElement extends CarElement {
#Id
#Column(name="DEFINITION")
private char definition;
#Id
#Column(name="DEP_NR")
private Integer depNr;
#Id
#Column(name="USR_DEP_NR")
private Integer usrDepNr;
#Id
#Column(name="FORIGN_ELEMENT")
private String userName;
#Id
#Column(name="STATE")
private String state;
#ManyToOne(fetch = FetchType.LAZY)
#JoinColumnsOrFormulas(value = {
#JoinColumnOrFormula(formula=#JoinFormula(value="COALESCE(NULLIF(DEP_NR, 0), USR_DEP_NR)", referencedColumnName="DEP_NR")),
#JoinColumnOrFormula(column=#JoinColumn(name="FORIGN_ELEMENT", referencedColumnName="USER_NAME", insertable = false, updatable = false)),
#JoinColumnOrFormula(column=#JoinColumn(name="STATE", referencedColumnName="STATE", insertable = false, updatable = false))
})
private Car car;
}
Join formulas are very fragile in Hibernate for the time being; I always had a difficult time to get them work properly.
The workaround that helped me often was to create database views which exposed the proper columns (including foreign keys that don't exist in the original tables). Then I mapped the entities to the views using classing Hibernate/JPA mappings.
Sometimes there are redundant joins in the generated SQL when using such entities, but the database optimizes such queries in most cases so that the execution plan is optimal anyway.
Another approach could be using #Subselects, which are some kind of Hibernate views, but I expect them to be less performant than the classic database views.
I ran into the cast exception as well and I'm on Hibernate 5.x.
Until Hibernate dedicates time to fix the issue, I found that while this guy's approach may not be cleanest (he even eludes to that fact!), it works.
You just need to add the #Column mappings (and get/set methods) to your association table objects that are returning null and manually set the values when you populate the relation data. Simple but effective!