With Bean Validation 2.0 it is possible to also put constraints on container elements.
I cannot get this to work with Kotlin data classes:
data class Some(val someMap: Map<String, #Length(max = 255) String>)
This does not have any effect. Any ideas?
I created a repository with a sample project to reproduce the case: https://github.com/mduesterhoeft/bean-validation-container-constraints
Add this config to your build.gradle (note that ... means whatever is already there) :
Groovy:
compileKotlin {
kotlinOptions {
freeCompilerArgs = [..., "-Xemit-jvm-type-annotations"]
...
}
}
Kotlin DSL:
tasks.withType<KotlinCompile> {
kotlinOptions {
freeCompilerArgs = listOf(..., "-Xemit-jvm-type-annotations")
...
}
}
Starting Kotlin 1.3.70 and 1.4, this should be possible setting a specific compiler option: https://kotlinlang.org/docs/reference/whatsnew14.html#type-annotations-in-the-jvm-bytecode .
On any previous version or any situation where this support is not sufficient, you have to write a custom validator.
Example one for validating that a collection only contains hex strings:
#Target(
AnnotationTarget.FUNCTION,
AnnotationTarget.PROPERTY_GETTER,
AnnotationTarget.PROPERTY_SETTER,
AnnotationTarget.FIELD,
AnnotationTarget.ANNOTATION_CLASS,
AnnotationTarget.CONSTRUCTOR,
AnnotationTarget.VALUE_PARAMETER
)
#Retention(AnnotationRetention.RUNTIME)
#MustBeDocumented
#Constraint(validatedBy = [HexStringElementsValidator::class])
annotation class HexStringElements(
val message: String = "must only contain hex values",
val groups: Array<KClass<*>> = [],
val payload: Array<KClass<out Any>> = []
)
class HexStringElementsValidator : ConstraintValidator<HexStringElements, Collection<Any>> {
companion object {
val pattern = "^[a-fA-F0-9]+\$".toRegex()
}
override fun isValid(value: Collection<Any>?, context: ConstraintValidatorContext?) =
value == null || value.all { it is String && pattern.matches(it) }
}
Related
it works fine if i change lateinit var id: String in the Payment.kt and CartPayment.kt to var id: String? = "", but the problem is i want the id to be required, how can i achieve that ?
The Error:
java.lang.RuntimeException: Unable to create application: io.realm.exceptions.RealmMigrationNeededException: Migration is required due to the following errors:
- Property 'CartPayment.id' has been made required.
- Property 'Payment.id' has been made required.
Model :
open class Payment() : RealmObject() {
#PrimaryKey
lateinit var id: String
var typeValue: Int = 0
var statusValue: Int = 0
var value: Double = 0.0
var referenceNumber: String? = null
Note: Payment and CartPayment models are identical except for the class name
Migration.kt
class Migration : RealmMigration {
override fun migrate(realm: DynamicRealm, oldVersion: Long, newVersion: Long) {
var oldVersion = oldVersion
val schema = realm.schema
if (oldVersion == 0L) {
schema.create("Payment")
.addField("id", String::class.java, FieldAttribute.PRIMARY_KEY)
.addField("typeValue", Int::class.java)
.addField("statusValue", Int::class.java)
.addField("value", Double::class.java)
.addField("referenceNumber", String::class.java)
schema.get("Order")!!
.addRealmListField("payments", schema.get("Payment")!!)
oldVersion++
}
if (oldVersion == 1L) {
schema.create("CartPayment")
.addField("id", String::class.java, FieldAttribute.PRIMARY_KEY)
.addField("typeValue", Int::class.java)
.addField("statusValue", Int::class.java)
.addField("value", Double::class.java)
.addField("referenceNumber", String::class.java)
schema.get("Order")!!
.addField("cashPaymentAmount", Float::class.java)
.addField("change", Float::class.java)
oldVersion++
}
}
}
App.kt
class App: Application() {
override fun onCreate() {
super.onCreate()
Realm.init(this)
val realmConfig = RealmConfiguration.Builder()
.schemaVersion(2)
.migration(Migration())
.build()
Realm.getInstance(realmConfig)
Realm.setDefaultConfiguration(realmConfig)
Fresco.initialize(this)
}
}
.addField("id", String::class.java, FieldAttribute.PRIMARY_KEY, FieldAttribute.REQUIRED)
did the trick.
if you declare the variable to be lateinit, make sure to add FieldAttribute.REQUIRED.
Basically you are adding a new field "id" which is primary key (hence required key).
If you do not specify any value while initialisation (lateinit), how will realm migrate all the earlier records, which doesn't have an id, but is required after migration ? Hence the error.
Below solutions might work
Either pre-populate the id's (without using lateinit)
Transform your earlier records to have id's if they don't have
Check the official examples here
For me, it happened after I have done the Migration.
I have made a non-nullable object in Kotlin and on migration I was creating a nullable wrapper type like Double, Int, etc.
Just use
Double::class.java
instead of
Double::class.javaObjectType
I've got an instance of an object, which I scan for memberProperties that have a proper annotation attached on them. Then, I want to filter based on their return type.
For example if declaration is as follows: class AutoValidatedThing : AutoValidatedUserInputComponent {...} and the target instance contains a #ValidComponent val someProperty: AutoValidatedThing = ..., I'd want to get the someProperty as a AutoValidatedUserInputComponent to the end of the following code block:
val invalidOnes = this::class.memberProperties
.filter { it.javaField != null && it.javaField!!.isAnnotationPresent(ValidComponent::class.java) }
.filter { val annotations = it.javaField?.annotations; annotations != null
&& annotations.map { ann -> ann.annotationClass }.contains(ValidComponent::class)
&& it.returnType is AutoValidatedUserInputComponent }
.map { it.getter.call() as AutoValidatedUserInputComponent }
But it.returnType is AutoValidatedUserInputComponent ALWAYS returns false.
AutoValidatedUserInputComponent is a simple interface:
interface AutoValidatedUserInputComponent {
fun blabla() : SomeType
}
Calling returnType on a KProperty doesn't return an instance with the given type that you could do an is check against - it returns a reflection class describing the type, specificallyKType, which of course does not implement your interface. Instead of using is, you can call isSubTypeOf on it, and check if it's a subtype of another given KType.
For that call, you'll need to get a KType for your own interface - for this, you can use createType on its KClass:
val targetType = AutoValidatedUserInputComponent::class.createType(nullable = true)
The nullability part is up to you, and there are also other optional parameters for createType, if your interface would happen to have type parameters, for example.
Then, as I mentioned, you can use isSubTypeOf:
val invalidOnes = this::class.memberProperties
.filter { it.javaField != null && it.javaField!!.isAnnotationPresent(ValidComponent::class.java) }
.filter {
val annotations = it.javaField?.annotations
annotations != null
&& annotations.map { ann -> ann.annotationClass }.contains(ValidComponent::class)
&& it.returnType.isSubtypeOf(targetType)
}
.forEach {
println("Found field with annotation and given supertype: $it")
}
I'm porting a class from Java to Kotlin. This class declares hundreds of objects. Each object has a name property which is identical with the declared variable name of the object. Java reflection allows to use the declared name via reflection to set the object member name. Just saves one parameter in hundreds of constructors.
I try to do the same in Kotlin but can't figure out how to do the property setting. Here is some simplified test code:
import kotlin.reflect.full.companionObject
import kotlin.reflect.full.declaredMemberProperties
class MyTestObject() {
var name: String = "NotInitialized"
companion object {
val Anton = MyTestObject()
val Berta = MyTestObject()
val Caesar = MyTestObject()
}
}
fun main(args : Array<String>) {
println(MyTestObject.Anton.name) // name not yet initialized
// Initialize 'name' with the variable name of the object:
for (member in MyTestObject::class.companionObject!!.declaredMemberProperties) {
if (member.returnType.toString() == "myPackage.MyTestObject") {
println("$member: ${member.name}")
// Set 'name' property to 'member.name':
// ???
}
}
println(MyTestObject.Anton.name) // now with the initialized name
}
The ??? line is where I would like to get access to the name property of MyTestObject to set it to to member.name. I'm looking for a function similar to (member.toObject() as MyTestObject).name = member.name.
While kotlin-reflection strives to be type-safe, sometimes the type system and the inference logic are not enough to allow for the things like what you are trying to do in a type-safe way. So, you have to make unchecked casts, stating that your knowledge about the types is more than the compiler can infer.
In your case, it's enough to cast member so that you can pass the companion object instance into its .get(...) and use the result as a MyTestObject, replace the // ??? line with:
#Suppress("UNCHECKED_CAST")
(member as KProperty1<Any, MyTestObject>)
.get(MyTestObject::class.companionObject!!.objectInstance!!)
.name = member.name
If you can replace MyTestObject::class.companionObject!! with MyTestObject.Companion::class (i.e. your actual use case does not involve getting .companionObject from different classes), the unchecked cast is not needed, and you can replace the statement above with this:
(member.get(MyTestObject.Companion) as MyTestObject).name = member.name
As an alternative that does not require companion object reflection at all, you can do the same binding logic with the delegation. Implementing provideDelegate allows you to customize the logic of initializing the property, and that's where you can assign the names:
operator fun MyTestObject.provideDelegate(
thisRef: MyTestObject.Companion,
property: KProperty<*>
) = apply { name = property.name }
operator fun MyTestObject.getValue(
thisRef: MyTestObject.Companion,
property: KProperty<*>
) = this
Then declare your properties as
val Anton by MyTestObject()
val Berta by MyTestObject()
val Caesar by MyTestObject()
Here is the final test code based on hotkey's solution:
package myPackage
import kotlin.reflect.full.declaredMemberProperties
class MyTestObject() {
lateinit var name: String
companion object {
val Anton = MyTestObject()
val Berta = MyTestObject()
val Caesar = MyTestObject()
init {
for (member in MyTestObject.Companion::class.declaredMemberProperties) {
if (member.returnType.toString() == "myPackage.MyTestObject") {
(member.get(MyTestObject.Companion) as MyTestObject).name = member.name
}
}
}
}
}
fun main(args : Array<String>) {
println(MyTestObject.Anton.name)
println(MyTestObject.Caesar.name)
}
So I have hundreds of fields in a couple of classes and I'd like to write some methods on them where they automatically println each field and its corresponding value
At the moment I have this:
inner class Version(val profile: Profile) {
#JvmField val MINOR_VERSION = glGetInteger(GL_MINOR_VERSION)
fun write(file: File? = null) {
//file.printWriter().use { out -> out.pri }
this::class.java.fields.forEach {
println(it.isAccessible)
println(it.getInt(it)) }
}
}
But this is what I get:
false
Exception in thread "main" java.lang.IllegalArgumentException: Can not set final int field uno.caps.Caps$Version.MINOR_VERSION to java.lang.reflect.Field
at sun.reflect.UnsafeFieldAccessorImpl.throwSetIllegalArgumentException(UnsafeFieldAccessorImpl.java:167)
at sun.reflect.UnsafeFieldAccessorImpl.throwSetIllegalArgumentException(UnsafeFieldAccessorImpl.java:171)
at sun.reflect.UnsafeFieldAccessorImpl.ensureObj(UnsafeFieldAccessorImpl.java:58)
at sun.reflect.UnsafeQualifiedIntegerFieldAccessorImpl.getInt(UnsafeQualifiedIntegerFieldAccessorImpl.java:58)
Any idea?
Instead of using Java fields and Java reflection code, you can also use Kotlin properties and Kotlin reflection classes:
class Reflector {
val Foo = 1;
fun printFields() {
this::class.memberProperties.forEach {
if (it.visibility == KVisibility.PUBLIC) {
println(it.name)
println(it.getter.call(this))
}
}
}
}
It seems that you are passing the Field variable it as a parameter getInt whereas the parameter should be the object the field belongs to this:
From the Javadoc for Field.getInt(Object obj):
obj - the object to extract the int value from
Perhaps this is what you meant to do:
class Reflector {
#JvmField val Foo = 1;
fun printFields() {
this.javaClass.fields.forEach {
println(it.isAccessible)
println(it.getInt(this))
}
}
}
fun main(args : Array<String>) {
Reflector().printFields()
}
I'm using TornadoFX 1.7.5 and I can't seem to get bound properties to work. I have the below ItemViewModels
class DynamicMenuViewModel : ItemViewModel<DynamicMenu>(DynamicMenu()) {
val title = bind { item?.title?.toProperty() }
val isBold = bind { item?.isBold?.toProperty() }
val routes = bind { item?.routes?.toProperty() }
}
data class DynamicMenu(var title: String = "", var isBold: Boolean = false, var routes: MutableList<MenuRouteViewModel> = mutableListOf())
class MenuRouteViewModel : ItemViewModel<MenuRoute>(MenuRoute()) {
val url = bind { item?.url?.toProperty() }
val title = bind { item?.title?.toProperty() }
val isBold = bind { item?.isBold?.toProperty() }
val showNew = bind { item?.showNew?.toProperty() }
}
data class MenuRoute(var url: String = "", var title: String = "", var showNew: Boolean = false, var isBold: Boolean = false)
Which are bound like this:
//routesController.dynamicMenu is an instance of DynamicMenuViewModel()
textfield(property = routesController.dynamicMenu.title) {
prefWidth = formWidth * .5
gridpaneConstraints {
columnRowIndex(0, 1)
marginLeft = 10.0
columnSpan = 2
marginBottom = 20.0
}
}
checkbox(property = routesController.dynamicMenu.isBold){
gridpaneConstraints {
columnRowIndex(2, 1)
marginLeft = 15.0
marginBottom = 20.0
}
}
Then the following functions commit the models and prints them to the screen when I click a button:
fun onClick(){
commitModel()
println(dynamicMenu.item.toString())
dynamicMenu.item.routes.forEach {
println(it.item.toString())
}
}
fun commitModel(){
dynamicMenu.item.routes.forEach {
it.commit()
}
dynamicMenu.commit()
}
The problem is that when I run the program and edit the textfields and checkboxes then click the button that runs onClick(), the backing item doesn't seem to be getting updated. So none of the updated values are printed to the console.
What am I doing wrong here?
The ViewModel can as you probably know only bind bidirectionally against JavaFX Properties. Your domain objects doesn't contain JavaFX properties, so you need to convert them. However, the toProperty() function you are using only operates on a value, and turns it into a Property. This property has no way of knowing about it's field owner, and hence cannot write back into the domain object.
Luckily, you can use the observable function to make your domain object properties writable as well:
val url = bind { item?.observable(MenuRoute::url) }
Since the observable function operates on a specific instance of a MenuRoute object, it now has enough information to write back into that instance when you commit() the model.
If you would consider changing the properties in your domain objects to be observable, you could write:
val url = bind(MenuRoute::url)
You can use the TornadoFX IDEA plugin inspection "Convert all properties to TornadoFX Properties" to automatically rework your properties. This would transform your MenuRoute object into:
class MenuRoute {
val isBoldProperty = SimpleBooleanProperty(false)
var isBold by isBoldProperty
val showNewProperty = SimpleBooleanProperty(false)
var showNew by showNewProperty
val urlProperty = SimpleStringProperty("")
var url by urlProperty
val titleProperty = SimpleStringProperty("")
var title by titleProperty
}
(You have to manually remove the data modifier on your class. Also beware that the current version of the plugin has a bug in the conversion function that would leave the old parameters - a new version will be released shortly).
If you don't want to do that for various reasons, I was just able to support that nice syntax even for mutable vars like you have, so from TornadoFX 1.7.6 you can use this syntax in your binding statements even if you don't want to change your data classes:
val url = bind(MenuRoute::url)