In Kotlin, it is idiomatic to deal with return value that could have or not a result with nullable types since they are natively supported by the language. This commit adds CrudRepository.findByIdOrNull(…) variant to CrudRepository#findById that returns T? instead of Optional<T>.
Original pull request: #299.
We now correctly calculate the number of defaulting masks used to represent constructor arguments. Previously, we've been one off which caused that Kotlin classes with 32/33 parameters weren't able to be instantiated.
We also now reuse KotlinDefaultMask to apply defaulting calculation and removed code duplicates.
We now use the primary constructor of Kotlin classes to discover the copy method. We use the primary constructor args to compare signatures and only use the copy method that takes all parameters in the constructor args order. This allows to find the appropriate copy method in case the class declares multiple copy methods.
We now also cache the copy method (KCallable) to reduce lookups in BeanWrapper.
Original pull request: #312.
We now support updating of immutable Kotlin data objects by creating new copies through Kotlin's copy method that is generated along with data classes and immutable properties.
data class DataClassKt(val id: String) {
}
data class ExtendedDataClassKt(val id: String, val name: String) {
}
We now calculate the number of expected default masks to filter synthetic constructors that do not match the expected parameter count. A Kotlin constructor with argument defaulting generates a synthetic integer argument for every 32 constructor arguments. This is independent of the number of actual optional arguments.
Previously, we used an non-exact check to consider constructors as default ones if they had at least two additional arguments. This caused the wrong constructor being used if the non-synthetic types matched the types of the default constructor.
We now determine initial values for primitive parameters in Kotlin constructors that are absent (null) and defaulted. We default all Java primitive types to their initial zero value to prevent possible NullPointerExceptions. Kotlin defaulting uses a bitmask to determine which parameter should be defaulted but still requires the appropriate type.
Previously, null values were attempted to cast/unbox and caused NullPointerException even though they had default values through Kotlin assigned.
Original pull request: #255.
Throw MappingInstantiationException from KotlinClassGeneratingEntityInstantiator if instantiation fails to align behavior with ClassGeneratingEntityInstantiator. Report Kotlin constructor instead of Java constructor if available.
Original pull request: #255.
We now resolve Kotlin interface properties to inspect these for nullability. Kotlin-reflect does not resolve interface property accessors yet so we need to handle this aspect ourselves.
Related ticket: https://youtrack.jetbrains.com/issue/KT-20768.
Original pull request: #254.
We now only inspect regular Kotlin classes with inspection to adapt Kotlin-specific behavior. Multipart-, synthetic and unknown classes are not supported. In such cases we fall back to the JVM reflection mechanism.
Non-regular classes are typically synthetic stubs, lambdas and SAM conversion which do not represent typical domain objects but rather technical bridge code.
Original pull request: #245.
We now fall back to default preferred constructor discovery if a Kotlin class has no primary constructor and no preferred constructor is resolved. Previously, primary constructor resolution yielded no result (returned null) which caused the subsequent Java constructor lookup to fail.
Original pull request: #244.
We now validate query method invocations to check method parameters whether they accept null values and reject execution if null values are not supported. We derive nullability support from repository interfaces declared using Kotlin and Spring's NonNullApi/Nullable annotations.
We also check whether a query method can return null. If a query method returns null which isn't supposed to do so, then we throw EmptyResultDataAccessException to prevent null return values.
interface UserRepository extends Repository<User, String> {
List<User> findByLastname(@Nullable String firstname);
@Nullable
User findByFirstnameAndLastname(String firstname, String lastname);
}
interface UserRepository : Repository<User, String> {
fun findByLastname(username: String?): List<User>
fun findByFirstnameAndLastname(firstname: String, lastname: String): User?
}
Original pull request: #241.
Moved PreferredConstructorDiscoverers into PreferredConstructorDiscoverer to hide more API. Renamed ClassGeneratingKotlinEntityInstantiator to KotlinClassGeneratingEntityInstantiator.
Use org.springframework.util.Assert instead of com.mysema.commons.lang.Assert.
Original pull request: #233.
We now discover Kotlin constructors and apply parameter defaulting to allow construction of immutable value objects. Constructor discovery uses primary constructors by default and considers PersistenceConstructor annotations.
KotlinClassGeneratingEntityInstantiator can instantiate Kotlin classes with default parameters by resolving the synthetic constructor. Null values translate to parameter defaults.
class Person(val firstname: String = "Walter") {
}
class Address(val street: String, val city: String) {
@PersistenceConstructor
constructor(street: String = "Unknown", city: String = "Unknown", country: String) : this(street, city)
}
Original pull request: #233.
