Hi there! How would I treat (im)mutable collection...

# spring

[kschlesselmann]

Hi there! How would I treat (im)mutable collections in my Spring Data (Mongo) entities? I have the following setup

@Document
class Foo(
        test: Set<String>,
        val id: UUID = UUID.randomUUID()
) {

    private val _test: MutableSet<String> = test.toMutableSet()

    val test: Set<String>
        get() = _test

    override fun equals(other: Any?): Boolean {
        if (this === other) return true
        if (javaClass != other?.javaClass) return false

        other as Foo
        return id == other.id
    }

    override fun hashCode(): Int = id.hashCode()
}

@Repository
interface FooRepository : ReactiveCrudRepository<Foo, UUID>

along with the following test

@DataMongoTest
internal class MutableCollectionTest(
        @Autowired private val fooRepository: FooRepository
) {

    @Test
    fun `should save and retrieve Foo`() {
        // Given
        val foo = Foo(setOf("a", "b"))

        // When
        val result = fooRepository.save(foo)
                .then(fooRepository.findById(foo.id))

        // Then
        StepVerifier.create(result)
                .expectNext(foo)
                .verifyComplete()
    }
}

and it fails with: No property test found on entity class ….Foo to bind constructor parameter to!

[thanksforallthefish]

would

@org.springframework.data.annotation.Transient
val test...

work?

@Transient: By default all private fields are mapped to the document, this annotation excludes the field where it is applied from being stored in the database

source: https://docs.spring.io/spring-data/mongodb/docs/current/reference/html/#mapping-usage-annotations

make sure you are not using javax.persistence.Transient though, that is for jpa only

[thanksforallthefish]

actually looking at your code again, the annotation might go on test in the constructor, as that is the property that is tried to be persisted but fails. but I am just guessing to be honest

[kschlesselmann]

Looks like I got a solution …
1. @Value("#root._test") test: … in the constructor and make then
2. private var(!) _test … as backing property