Spring HATEOAS. Embedded resource + ability to CRUD it? - json

Question

In typical situation with embedded resources:
#Entity #Data
class Item {
id, name
...
#ManyToOne
#JoinColumn(name="status", referencedColumnName="ID")
private Status status;
}
#Entity #Data
class Status {
id, name
...
#JsonIgnore //break infinite reference loop during serialization
#OneToMany(mappedBy="status")
private List<Item> items;
}
Instead of having links to Status id's in Item JSON, I want to INCLUDE Status object in Item JSON
{
"itemName": "abc",
... ,
"status": {
"statusName":"ACTIVE",
...
}
"_links": {
...
}
}
I managed embedding doing any of the following:
Marking Item class status property as #RestResource(exported=false)
#Entity #Data
class Item {
...
#RestResource(exported=false) // <-- HERE
#ManyToOne
#JoinColumn(name="status", referencedColumnName="ID")
private Status status;
Marking Status repo interface #RepositoryRestResource(..., exported=false)
#RepositoryRestResource(collectionResourceRel="statuses", path="status", exported=false)
public interface StatusRepository extends JpaRepository<Status, String>
Deleteting repository for Status entity
// DELETED
#RepositoryRestResource
public interface StatusRepository extends JpaRepository<Status, String>{}
QUESTION:
Any of that embeds Status into Item JSON like I want, but I do not have an access to Status Repository anymore to get a Status object by it's ID or do any CRUD on it.
How to embed status in parent Item JSON and still CRUD status via url?

Answer 1

I implemented it as follows:
#Entity #Data
class Item {
#Id
#GeneratedValue(generator = "uuid2")
#GenericGenerator(name = "uuid2", strategy = "uuid2")
String id;
String name
#RestResource(exported = false) // <---- ADDED
#ManyToOne
#JoinColumn(name="status", referencedColumnName="ID")
private Status status;
}
#Entity #Data
class Status {
#Id
#GeneratedValue(generator = "uuid2")
#GenericGenerator(name = "uuid2", strategy = "uuid2")
String id
String name
// <-------- DELETED REFERENCE TO PARENT OBJECT
//#OneToMany(mappedBy="status")
//private List<Item> items;
}
Repositories for both Entities exist so it is possible to do CRUD on Status entity as well
#RepositoryRestResource(collectionResourceRel="items", path="items")
public interface StatusRepository extends JpaRepository<Item, String>
{}
#RepositoryRestResource(collectionResourceRel="statuses", path="statuses")
public interface StatusRepository extends JpaRepository<Status, String>
{}
For future generations I'll leave it here.
For convenience:
1) Exposed ids for entities in JSON
/**
* Exposing Ids as properties for entities specified
*/
#Configuration
public class ExposeIdConfig extends RepositoryRestMvcConfiguration {
#Override
protected void configureRepositoryRestConfiguration(RepositoryRestConfiguration config) {
config.exposeIdsFor(Item.class, Status.class);
}
}
So getting list of items looks like:
{
"_links": {
"self": {
"href": "http://localhost:8080/app/items{?page,size,sort}",
"templated": true
}
},
"_embedded": {
"as": [
{
"id": "29117425-f011-4ff9-8952-38b05d3df7f0",
"name": "item 1",
"status": {
"id": "e9192ae7-29f8-4d5e-ad62-cad8d87de9e2",
"name": "ACTIVE"
},
"_links": {
"self": {
"href": "http://localhost:8080/app/items/29117425-f011-4ff9-8952-38b05d3df7f0"
}
},
...
}