Using Jackson with Retrofit, I wanted to have list of friends set to friendToMany during Deserialization. As I have gone through with documentation, we have to manually assign that entity to boxstore when assignable=true is set. So, I am doing this way(as shown in code). This approach works only for first item which this code is part of. It doesn't work for element 2 or further.
#Id(assignable = true)
#JsonProperty("_id")
public long id;
#Transient
private List<Friend> friends = null;
#JsonIgnore
#Backlink(to = "demoResponseToOne")
ToMany<Friend> friendToMany;
#JsonProperty("friends")
public void setFriends(
List<Friend> friends)
{
this.friends = friends;
for (Friend friend : friends)
{
MyApplication.getBoxStore().boxFor(Friend.class).attach(friend);
friendToMany.add(friend);
}
}
Exception thrown is : io.objectbox.exception.DbDetachedException: Cannot resolve relation for detached entities, call box.attach(entity) beforehand. at the time of add(friend). I mean this works when this Root element is first item of list.
You need to attach the Box<Friend> to this as well, which owns the ToMany to be modified:
MyApplication.getBoxStore().boxFor(Friend.class).attach(this);
Background: If you are using #Id(assignable = true) you need to take care of some things that ObjectBox would normally do for you. This includes attaching the Box before modifying any ToMany.
Source:
https://docs.objectbox.io/relations#updating-tomany
https://docs.objectbox.io/advanced/object-ids#self-assigned-object-ids
Related
I am having problems with ObjectBox in my Android app. Everything works, except for this issue, so I know my entity classes are OK.
It's an inventory that makes it possible to do inventories of multiple shops (stores). Each InventoryItem is a product that was scanned when doing the inventory. When the inventory is concluded, one or more text files are generated from the data in the box.
One file is generated for each shop, so I have this code to find which distinct shops were inventoried:
Box<InventoryItem> box = app.getBoxStore().boxFor(InventoryItem.class);
long[] shopIds = box.query()
.build()
.property(InventoryItem_.shopId)
.distinct()
.findLongs();
I get the following when this code runs (only relevant part of the stacktrace):
Caused by: java.lang.IllegalArgumentException: Property "shopId" is of type Relation, but we expected a property of type Long in this context
at io.objectbox.query.PropertyQuery.nativeFindLongs(Native Method)
at io.objectbox.query.PropertyQuery$2.call(PropertyQuery.java:213)
at io.objectbox.query.PropertyQuery$2.call(PropertyQuery.java:210)
at io.objectbox.BoxStore.callInReadTx(BoxStore.java:709)
at io.objectbox.BoxStore.callInReadTxWithRetry(BoxStore.java:654)
at io.objectbox.query.Query.callInReadTx(Query.java:273)
at io.objectbox.query.PropertyQuery.findLongs(PropertyQuery.java:210)
at br.com.donadio.inventario.view.ExportDialog$GenerateFilesAsync.doInBackground(ExportDialog.java:132)
at br.com.donadio.inventario.view.ExportDialog$GenerateFilesAsync.doInBackground(ExportDialog.java:104)
at android.os.AsyncTask$2.call(AsyncTask.java:305)
at java.util.concurrent.FutureTask.run(FutureTask.java:237)
at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:243)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1133)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:607)
at java.lang.Thread.run(Thread.java:761)
I also tried using .property(InventoryItem_.shop.targetIdProperty) in the query, but it gives the exact same error. I can't find another way to do this, nor a way to fix my code.
I'm using AndroidX (not that it should matter) and my project is correctly setup for it.
MinSdk is 19, MaxSdk is 28, targetSdk is 28.
ObjectBox version is 2.2.0.
Debugging on a device running Android 7.1.1.
These are the relevant entities:
#Entity
public class InventoryItem
{
#Id
public long id;
public String operator;
public ToOne<Area> area;
public long areaId; // expose relationship target ID
public ToOne<Product> product;
public long productId; // expose relationship target ID
public ToOne<Shop> shop;
public long shopId; // expose relationship target ID
public Date timestamp;
// ...
}
#Entity
public class Shop
{
#Id(assignable=true)
public long id;
#Index #Unique
public String name;
#Backlink
public ToMany<InventoryItem> inventoryItems;
// ...
}
After looking a lot for an answer in ObjectBox's GitHub and here, I came up with a solution, based on this answer on the project's GitHub:
List<InventoryItem> items = box.getAll();
ArrayList<Shop> shops = new ArrayList<>();
for (InventoryItem item : items)
{
Shop shop = item.shop.getTarget();
if (!shops.contains(shop))
shops.add(shop);
}
So, we just find everything and then iterate through the list, getting distinct objects in an ArrayList (or I could just get the Id's into a long[]) . Just a handful more lines of code...
Still, I consider that a bug in ObjectBox's implementation, as it's returning a relationship instead of a property on a long attribute. I'm opening an issue.
Workaround I found is to write your query using the object you want the ID from as the starting class.
In your case, that would be :
QueryBuilder<Shop> qb = app.getBoxStore().boxFor(Shop.class).query(); // Start with Shop if what you need are Shop IDs
qb.link(Shop_.inventoryItems); // Filter on working inventoryItems links
long[] shopIds = qb.build()
.property(Shop_.id)
.distinct()
.findLongs(); // Get your IDs
instead of
Box<InventoryItem> box = app.getBoxStore().boxFor(InventoryItem.class);
long[] shopIds = box.query()
.build()
.property(InventoryItem_.shopId)
.distinct()
.findLongs();
I am conducting some Neo4J tests and running into the following peculiar problem. I created a small model which I'm intending to use with OGM. The model has a superclass Entity and a child class Child. They're both in package persistence.model. Entity has the required Long id; with matching getId() getter.
public abstract class Entity {
private Long id;
public Long getId() {
return id;
}
}
#NodeEntity
Child extends Entity {
String name;
public Child() {
}
}
Creating Child objects and persisting them through OGM works fine. I'm basing myself on the examples found in the documentation and using a Neo4jSessionFactory object, which initialises the SessionFactory with the package persistence.model. The resulting database contains objects with proper ID's filled in.
The problem arises when I try to fetch a Child for a given ID. I'm trying it with three methods, using two connection systems (bolt and ogm):
boltSession.run("MATCH (a:Child) WHERE id(a) = {id} RETURN a", parameters("id", childId));
ogmSession.query("MATCH (a:Child) WHERE id(a) = $id RETURN a", params);
ogmSession.load(Child.class, childId, 1);
The first two methods actually return the correct data. The last one returns a null value. The last one, using OGM, has some obvious benefits, and I'd love to be able to use it properly. Can anyone point me in the right direction?
In your test code you are doing a lookup by id of type int.
private int someIdInYourDatabase = 34617;
The internal ids in Neo4j are of type Long.
If you change the type of the id to long or Long then it will work.
private long someIdInYourDatabase = 34617;
Hi considering the following example:
Resource:
#PUT
#Path("{id}")
public Response update(#PathParam(value = "id") final String id, final Person person) {
final Person person = service.getPerson(id);
final EntityTag etag = new EntityTag(Integer.toString(person.hashCode()));
// If-Match is required
ResponseBuilder builder = request.evaluatePreconditions(etag);
if (builder != null) {
throw new DataHasChangedException("Person data has changed: " + id);
}
service.updatePerson(id, person.getName());
....
}
Service:
public void updatePerson(final String id, final String name) {
final Query<Person> findQuery = morphiaDataStore.createQuery(Person.class).filter("id ==", id);
UpdateOperations<Person> operation = morphiaDataStore.createUpdateOperations(Person.class).set("name", name);
morphiaDataStore.findAndModify(findQuery, operation );
}
Person:
#Entity("person")
public class Person {
#Id
private ObjectId id;
#Version
private Long version;
private String name;
...
}
I do check if the etag provided is the same of the person within the database. However this check is been done on the resource itself. I don't think that this is safe since the update happens after the check and another thread could have gone threw the check in the meantime. How can this be solved correctly? Any example or advise is appreciated.
Morphia already implements optimistic-locking via #Version annotation.
http://mongodb.github.io/morphia/1.3/guides/annotations/#version
#Version marks a field in an entity to control optimistic locking. If the versions change in the database while modifying an entity (including deletes) a ConcurrentModificationException will be thrown. This field will be automatically managed for you – there is no need to set a value and you should not do so. If another name beside the Java field name is desired, a name can be passed to this annotation to change the document’s field name.
I see you have already use the annotation in your example. Make sure the clients include the version of the document as part of the request so you can also pass it to morphia.
Not sure if findAndModify will be able to handle it (I would think it does). but at least I'm sure save does handle it.
Assuming the object person contains the new name and version that the client was looking at, you can do directly something like this to update the record:
morphiaDataStore.save(person);
If there was another save before this client could pick it up the versions will no longer match and a ConcurrentModificationException will be issued with this message:
Entity of class %s (id='%s',version='%d') was concurrently updated
In old version, SDN3, I can use findById(List id), but after upgrade to SDN4, I cannot use this function again, always return empty.
This is my sample class :
#NodeEntity
public class Right{
#GraphId
Long graphId;
String id; //random generated UUID
String name;
//Properties & Constructor
}
And then I have RightRepository that contain these code :
public interface RightRepository extends GraphRepository<Right> {
List<Right> findById(List<String> id);
}
Instead of use Loop to get per ID, I need to call repository only once, and get the List (without using findAll())
Is SDN4 already not support it? Is there any other solution?
As I post in a comment and after a further investigation, I think that a custom query is the only way to accomplish your requirement at the moment. This works:
#Query("MATCH (n:Right) WHERE n.id IN {rightIds} RETURN n")
List<Right> findRightById(#Param("rightIds") List<String> rightIds);
Hope it helps
i've hit a block once again with hibernate.I've posted numerous times on different aspects of the user and contact management that i've been building.
The sad thing is that i didn't really have the time to play with it and understand it better before actually starting working with it. Sorry but English is not my native language, i rather speak french. And again i've started coding in java in an autodidact way.i'm doing all of this by reading books and haven't gone to school for it. with time constraints it's hard to read a book from beginning to the end.
I'm not sure i should put every of my codes dealing with an issue here and from what i've learned from other forum is to post just the necessary and being concise.
So in my User model i have UserAccount class, Profile that holds details like name, preferences etc , AccountSession and Phone.
my contact management model have Contact and Group.
UserAccount has one-to-one association with Profile, one-to-many with AccountSession,contact and group, all bidirectional.the one-to-many association with phone is unidirectional because contact also has and unidirectional with Phone.
Contact has a bidirectional many-o-many with group and one-to-many with phone that i said earlier.
Group also has a many-to-many bedirectional with contact.
here are the mappings
// UserAccount
......
#OneToOne(targetEntity=UserProfileImpl.class,cascade={CascadeType.ALL})
#org.hibernate.annotations.Cascade(value=org.hibernate.annotations.CascadeType.DELETE_ORPHAN)
#JoinColumn(name="USER_PROFILE_ID")
private UserProfile profile;
#OneToMany(targetEntity=ContactImpl.class, cascade={CascadeType.ALL}, mappedBy="userAccount")
#org.hibernate.annotations.Cascade(value=org.hibernate.annotations.CascadeType.DELETE_ORPHAN)
private Set<Contact> contacts = new HashSet<Contact>();
#OneToMany(targetEntity=GroupImpl.class, cascade={CascadeType.ALL}, mappedBy="userAccount")
#org.hibernate.annotations.Cascade(value=org.hibernate.annotations.CascadeType.DELETE_ORPHAN)
private Set<Group> groups = new HashSet<Group>();
.......
//Group
#ManyToOne(targetEntity=UserAccountImpl.class)
#JoinColumn(name="USER_ACCOUNT_ID",nullable=false)
private UserAccount userAccount;
#ManyToMany(targetEntity=ContactImpl.class,cascade={CascadeType.PERSIST, CascadeType.MERGE})
#JoinTable(name="GROUP_CONTACT_MAP", joinColumns={#JoinColumn(name="GROUP_ID")},
inverseJoinColumns={#JoinColumn(name="CONTACT_ID")})
private Set<Contact> contacts = new HashSet<Contact>();
//Contact
....
#ManyToOne(targetEntity=UserAccountImpl.class)
#JoinColumn(name="USER_ACCOUNT_ID",nullable=false)
private UserAccount userAccount;
#ManyToMany(targetEntity=GroupImpl.class, mappedBy="contacts")
private Set<Group> groups=new HashSet<Group>();
....
// helper methods from group
public void addContact(Contact contact) {
try{
this.getContacts().add(contact);
contact.getGroups().add(this);
}catch(Exception e) {
}
}
//helper method from group
public void removeContact(Contact contact) {
contact.getGroups().remove(contact);
this.getContacts().remove(contact);
}
//helper method from contact
public void addGroup(Group group) {
try{
this.getGroups().add(group);
group.getContacts().add(this);
} catch(Exception e) {
e.printStackTrace();
}
}
//Helper method from group
public void removeGroup(Group group){
try{
group.getContacts().remove(this);
this.getGroups().remove(group);
} catch(Exception e) {
e.printStackTrace();
}
}
//UserAccount setter from Contact.All the children with many-to-one have the same
/**
* #param userAccount the userAccount to set
*/
public void setUserAccount(UserAccount userAccount) {
this.userAccount = userAccount;
}
I'ld like to pull the UserAccount by its email field which is an unique field in the UserAccount table.
In the UserAccountDAO the method i call to get the UserAccount is getUserAccountByEmail here below.So i expect this method to load all the children collections of the UserAccount namely its Contact collection, group collection.I want it in such a way that when UserAccount is loaded with Contacts collection each of the contact object has its reference with its belonging groups collection if any etc and vice versa.
public UserAccount getUserAccountByEmail(String email) {
// try {
logger.info("inside getUserAccountByEmail");
logger.debug(email);
Session session = (Session) this.getDBSession().getSession();
UserAccount user = (UserAccount) session.createCriteria(this.getPersistentClass())
.setFetchMode("contacts", FetchMode.SELECT) //recently added
.setFetchMode("groups", FetchMode.SELECT) // recently added
.add(Restrictions.eq("email", email))
.uniqueResult();
logger.debug(user);
return user;
// } catch(NonUniqueResultException ne) {
// logger.debug("Exception Occured: getUserAccountByEmail returns more than one result ", ne);
// return null;
// } catch(HibernateException he){
// logger.debug("Exception Occured: Persistence or JDBC exception in method getUserAccountByEmail ",he);
// return null;
// }catch(Exception e) {
// logger.debug("Exception Occured: Exception in method getUserAccountByEmail", e);
// return null;
// }
Since there has to be an UserAccount before any contact and groups, in my unit test when testing the saving of a contact object for which there must be an existing group i do this in order
a create userAccount object ua.
b create group object g1;
c create contact object c1;
d ua.addGroup(g1);
e c1.setUserAccount(ua);
f c1.addGroup(g1);
g uaDao.save(ua); // which saves the group because of the cascade
h cDao.save(c1);
Most of the time i use the session.get() from hibernate to pull c1 by its it id generated by hibernate and do all the assertions which works actually.
but in Integration test when i call getUserAccountByEmail with and without the setFetchMode and it returns the right object but then all the children collections are empty. i've tried the JOIN and the SELECT.the query string changes but then the result set is still the same. So this arises some questions :
1. What should i do to fix this?
2. the helper method works fine but it's on the parent side(i do it in the test).What i've been wondering about is that doing c1.setUserAccount(ua); is enough to create a strong relationship between UserAccount and contact.most of the time there will not be cases where i save the userAccount with contact but yet the helper method that set the association in both side and which is in UserAccount will not been called before i save the contact for a particular userAccount.So i'm little confused about that and suspecting that setting of the association is part of the why something is not working properly.and then calling session.get(UserAccount.class, ua.getID()) i think goes what i want and i'ld like getUserAccountByEmail to do the same.
3. ChssPly76 thinks the mapping has to be rewrite.So i'm willing to let you guide me through this.I really need to know the proper way to do this because we can't lean everything from a good book.So i you think i should change the mapping just show me how.and probable i'm doing things the wrong way without even been aware of that so don't forget i'm still learning java itself.THanks for the advise and remarks and thanks for reading this
I agree with you that it seems likely that the associations between your parent objects and their child collections are not getting persisted properly. I always like to start out by looking at what is in the database to figure out what's going on. After you run your test what do you see in the actual database?
It seems likely that one of two things is happening (using UserAccount as an example):
The items in the child collection are not getting saved to the database at all, in which case you'll be able to see in the database that there are no records associated with your UserAccount. This could be caused by saving the UserAccount object before you've added the child object to the UserAccount's collection.
The items in the child collection are getting saved to the database, but without the needed association to the parent object, in which case you'll see rows for your child items but the join column (ie 'userAccount' will be null). This could be caused by not setting the userAccount() property on the child object.
These are the two scenarios that I've run into where I've seen the problem you describe. Start by taking a look at what goes into your database and see if that leads you farther.