I have a big project and I'm planning to inject ViewModel as seen on documentation:
#Singleton
class ViewModelFactory #Inject constructor(private val creators: Map<Class<out ViewModel>, #JvmSuppressWildcards Provider<ViewModel>>) : ViewModelProvider.Factory {
override fun <T : ViewModel> create(modelClass: Class<T>): T {
val creator = creators[modelClass]
?: creators.asIterable().firstOrNull { modelClass.isAssignableFrom(it.key) }?.value
?: throw IllegalArgumentException("unknown model class $modelClass")
return try {
creator.get() as T
} catch (e: Exception) {
throw RuntimeException(e)
}
}
}
#Target(AnnotationTarget.FUNCTION, AnnotationTarget.PROPERTY_GETTER, AnnotationTarget.PROPERTY_SETTER)
#MapKey
internal annotation class ViewModelKey(val value: KClass<out ViewModel>)
#Module
abstract class ViewModelModule {
#Binds
internal abstract fun bindViewModelFactory(viewModelFactory: ViewModelFactory): ViewModelProvider.Factory
#Binds
#IntoMap
#ViewModelKey(InitializationViewModel::class)
internal abstract fun bindInitializationViewModel(myViewModel: InitializationViewModel): ViewModel
}
But the problem I have is that I cannot find a way to inject on versions of pre-Dagger 2.10. I've tried to migrate the huge project to Dagger 2.21 with Android Injectors but I wasted 3 days with no success.
Does anyone achieve it?
Thanks
Related
I need to configure default coroutine context for all requests in Spring MVC. For example MDCContext (similar question as this but for MVC not WebFlux).
What I have tried
Hook into Spring - the coroutine code is here but there is no way to change the default behavior (need to change InvocableHandlerMethod.doInvoke implementation)
Use AOP - AOP and coroutines do not play well together
Any ideas?
This seems to work:
#Configuration
class ContextConfig: WebMvcRegistrations {
override fun getRequestMappingHandlerAdapter(): RequestMappingHandlerAdapter {
return object: RequestMappingHandlerAdapter() {
override fun createInvocableHandlerMethod(handlerMethod: HandlerMethod): ServletInvocableHandlerMethod {
return object : ServletInvocableHandlerMethod(handlerMethod) {
override fun doInvoke(vararg args: Any?): Any? {
val method = bridgedMethod
ReflectionUtils.makeAccessible(method)
if (KotlinDetector.isSuspendingFunction(method)) {
// Exception handling skipped for brevity, copy it from super.doInvoke()
return invokeSuspendingFunctionX(method, bean, *args)
}
return super.doInvoke(*args)
}
/**
* Copied from CoroutinesUtils in order to be able to set CoroutineContext
*/
#Suppress("UNCHECKED_CAST")
private fun invokeSuspendingFunctionX(method: Method, target: Any, vararg args: Any?): Publisher<*> {
val function = method.kotlinFunction!!
val mono = mono(YOUR_CONTEXT_HERE) {
function.callSuspend(target, *args.sliceArray(0..(args.size-2))).let { if (it == Unit) null else it }
}.onErrorMap(InvocationTargetException::class.java) { it.targetException }
return if (function.returnType.classifier == Flow::class) {
mono.flatMapMany { (it as Flow<Any>).asFlux() }
}
else {
mono
}
}
}
}
}
}
}
I am trying to translate the following reactive code into kotlin coroutines:
#GetMapping
fun getAllTodosMono(): Mono<CollectionModel<TodoItem>> =
repository
.findAll()
.collectList()
.flatMap { mkSelfLinkMono(it) }
private fun mkSelfLinkMono(list: List<TodoItem>): Mono<CollectionModel<TodoItem>> {
val method = methodOn(Controller::class.java).getAllTodosMono()
val selfLink = linkTo(method).withSelfRel().toMono()
return selfLink.map { CollectionModel.of(list, it) }
}
Coroutine Version:
#GetMapping
suspend fun getAllTodosCoroutine(): CollectionModel<TodoItem> =
repository
.findAll()
.collectList()
.awaitSingle()
.let { mkSelfLinkCoroutine(it) }
private suspend fun mkSelfLinkCoroutine(list: List<TodoItem>): CollectionModel<TodoItem> {
val method = methodOn(Controller::class.java).getAllTodosCoroutine()
val selfLink = linkTo(method).withSelfRel().toMono().awaitSingle()
return CollectionModel.of(list, selfLink)
}
However, I get a runtime error when trying to run the code.
java.lang.ClassCastException: class org.springframework.hateoas.server.core.LastInvocationAware$$EnhancerBySpringCGLIB$$d8fd0e7e cannot be cast to class org.springframework.hateoas.CollectionModel (org.springframework.hateoas.server.core.LastInvocationAware$$EnhancerBySpringCGLIB$$d8fd0e7e is in unnamed module of loader org.springframework.boot.devtools.restart.classloader.RestartClassLoader #62b177e9; org.springframework.hateoas.CollectionModel is in unnamed module of loader 'app')
I suspect methodOn(...) does not support suspend functions. The only solution that actually works is to build the link by hand instead of using the linkTo(...) function:
private fun mkSelfLink(list: List<TodoItem>): CollectionModel<TodoItem> {
return Link
.of("/api/v1/todos")
.withSelfRel()
.let { CollectionModel.of(list, it) }
}
However, I lose the ability to link to existing endpoints in my REST controller and also the host that is automagically added to the link uri.
Am I missing something?
EDIT: Here is the link to my github repo: https://github.com/enolive/kotlin-coroutines/tree/master/todos-coroutini
If you paste the following code sample into the TodoController replacing the original getTodo(...) method, you can see the failure I described above.
private suspend fun Todo.withSelfLinkByBuilder(): EntityModel<Todo> {
val method = methodOn(Controller::class.java).getTodo(id!!)
val selfLink = linkTo(method).withSelfRel().toMono().awaitSingle()
return EntityModel.of(this, selfLink)
}
#GetMapping("{id}")
suspend fun getTodo(#PathVariable id: ObjectId) =
repository.findById(id)?.withSelfLinkByBuilder()
?: throw ResponseStatusException(HttpStatus.NOT_FOUND)
Well, I found a solution, I don't know if is it a satisfactory one, but it works, none of the less.
By simple chaining the function calls together the runtime appears to work as intended:
private suspend fun mkSelfLinkCoroutine(list: List<TodoItem>): CollectionModel<TodoItem> {
val selfLink = linkTo(methodOn(Controller::class.java)
.getAllTodosCoroutine())
.withSelfRel()
.toMono()
.awaitSingle()
return CollectionModel.of(list, selfLink)
}
This is really strange, but it is what it is.
You probably forgot to add coroutines to your project. Add these dependencies to your gradle file:
implementation("org.jetbrains.kotlinx:kotlinx-coroutines-core")
implementation("org.jetbrains.kotlinx:kotlinx-coroutines-reactor")
I know this kind of question has been asked before.
I have a method which is annotated with #PostConstruct.
The methods assumes that all Flyway scripts have been executed before invocation.
It seems that Flyway also uses #PostConstruct annotated methods and that these methods are called after my method.
I tried to annotate my method with #DependOn and different flyway beennames.
Unfortunately without success. Can anybody help me.
Solution:
I would set a dependency on the FlywayMigrationInitializer in the constructor. When the Initializer is created and set up, the migrations are run.
Or you can depend on the flywayInitializer bean (#DependsOn("flywayInitializer")). The bean is named flywayInitializer, of the class FlywayMigrationInitializer and it is created in FlywayAutoConfiguration.java.
FlywayMigrationInitializer implements InitializingBean and calls the migrate method in the afterPropertiesSet method.
Example:
#Component
// #DependsOn("flywayInitializer")
#Slf4j
public class TestPostConstruct {
public TestPostConstruct(FlywayMigrationInitializer flywayForceInitialization) {
}
#PostConstruct
public void testPostConstruct() {
log.info("----> in testPostConstruct");
}
}
The Spring Boot log:
INFO 4760 --- [main] o.f.core.internal.command.DbMigrate : Successfully applied 1 migration to schema "PUBLIC" (execution time 00:00.130s)
INFO 4760 --- [main] c.example.flywayinit.TestPostConstruct : ----> in testPostConstruct
For new Flyway this work (use Flyway callbacks)
#Configuration
class FlywayConfig(env: Environment) {
private val env: Environment
init {
this.env = env
}
#Bean(initMethod = "migrate")
fun flyway(dbLoadService: DbLoadService): Flyway {
return Flyway(
Flyway.configure()
.baselineOnMigrate(true)
.dataSource(
env.getRequiredProperty("spring.datasource.url"),
env.getRequiredProperty("spring.datasource.username"),
env.getRequiredProperty("spring.datasource.password")
)
//запуск загрузки из базы после окончания миграции
.callbacks(FlywayMigrationsCompleteCallback {
dbLoadService.loadAllCertificateInformation()
})
)
}
class FlywayMigrationsCompleteCallback(private val callback: () -> Unit) : Callback {
override fun supports(event: Event?, context: Context?): Boolean {
return event == Event.AFTER_MIGRATE
}
override fun canHandleInTransaction(event: Event?, context: Context?): Boolean {
return true
}
override fun handle(event: Event?, context: Context?) {
callback()
}
override fun getCallbackName(): String {
return FlywayMigrationsCompleteCallback::class.simpleName!!
}
}
#Component
class DbLoadService(private val certificateRepository:CertificateRepository) {
#Volatile var certificate: List<Certificate>?=null
fun loadAllCertificateInformation(){
val findAll = certificateRepository.findAll()
runBlocking {
certificate = findAll.toList()
}
}
}
I have tried all 3 solutions suggested in what is the right way to handle errors in spring-webflux, but WebExceptionHandler is not getting called. I am using Spring Boot 2.0.0.M7. Github repo here
#Configuration
class RoutesConfiguration {
#Autowired
private lateinit var testService: TestService
#Autowired
private lateinit var globalErrorHandler: GlobalErrorHandler
#Bean
fun routerFunction():
RouterFunction<ServerResponse> = router {
("/test").nest {
GET("/") {
ServerResponse.ok().body(testService.test())
}
}
}
}
#Component
class GlobalErrorHandler() : WebExceptionHandler {
companion object {
private val log = LoggerFactory.getLogger(GlobalErrorHandler::class.java)
}
override fun handle(exchange: ServerWebExchange?, ex: Throwable?): Mono<Void> {
log.info("inside handle")
/* Handle different exceptions here */
when(ex!!) {
is ClientException -> exchange!!.response.statusCode = HttpStatus.BAD_REQUEST
is Exception -> exchange!!.response.statusCode = HttpStatus.INTERNAL_SERVER_ERROR
}
return Mono.empty()
}
}
UPDATE:
When I change Spring Boot version to 2.0.0.M2, the WebExceptionHandler is getting called. Do I need to do something for 2.0.0.M7?
SOLUTION:
As per Brian's suggestion, it worked as
#Bean
#Order(-2)
fun globalErrorHandler() = GlobalErrorHandler()
You can provide your own WebExceptionHandler, but you have to order it relatively to others, otherwise they might handle the error before yours get a chance to try.
the DefaultErrorWebExceptionHandler provided by Spring Boot for error handling (see reference documentation) is ordered at -1
the ResponseStatusExceptionHandler provided by Spring Framework is ordered at 0
So you can add #Order(-2) on your error handling component, to order it before the existing ones.
An error response should have standard payload info. This can be done by extending AbstractErrorWebExceptionHandler
ErrorResponse: Data Class
data class ErrorResponse(
val timestamp: String,
val path: String,
val status: Int,
val error: String,
val message: String
)
ServerResponseBuilder: 2 different methods to build an error response
default: handle standard errors
webClient: handle webClient exceptions (WebClientResponseException), not for this case
class ServerResponseBuilder(
private val request: ServerRequest,
private val status: HttpStatus) {
fun default(): Mono<ServerResponse> =
ServerResponse
.status(status)
.body(BodyInserters.fromObject(ErrorResponse(
Date().format(),
request.path(),
status.value(),
status.name,
status.reasonPhrase)))
fun webClient(e: WebClientResponseException): Mono<ServerResponse> =
ServerResponse
.status(status)
.body(BodyInserters.fromObject(ErrorResponse(
Date().format(),
request.path(),
e.statusCode.value(),
e.message.toString(),
e.responseBodyAsString)))
}
GlobalErrorHandlerConfiguration: Error handler
#Configuration
#Order(-2)
class GlobalErrorHandlerConfiguration #Autowired constructor(
errorAttributes: ErrorAttributes,
resourceProperties: ResourceProperties,
applicationContext: ApplicationContext,
viewResolversProvider: ObjectProvider<List<ViewResolver>>,
serverCodecConfigurer: ServerCodecConfigurer) :
AbstractErrorWebExceptionHandler(
errorAttributes,
resourceProperties,
applicationContext
) {
init {
setViewResolvers(viewResolversProvider.getIfAvailable { emptyList() })
setMessageWriters(serverCodecConfigurer.writers)
setMessageReaders(serverCodecConfigurer.readers)
}
override fun getRoutingFunction(errorAttributes: ErrorAttributes?): RouterFunction<ServerResponse> =
RouterFunctions.route(RequestPredicates.all(), HandlerFunction<ServerResponse> { response(it, errorAttributes) })
private fun response(request: ServerRequest, errorAttributes: ErrorAttributes?): Mono<ServerResponse> =
ServerResponseBuilder(request, status(request, errorAttributes)).default()
private fun status(request: ServerRequest, errorAttributes: ErrorAttributes?) =
HttpStatus.valueOf(errorAttributesMap(request, errorAttributes)["status"] as Int)
private fun errorAttributesMap(request: ServerRequest, errorAttributes: ErrorAttributes?) =
errorAttributes!!.getErrorAttributes(request, false)
}
I have been evaluating to adopt spring-data-mongodb for a project. In summary, my aim is:
Using existing XML schema files to generate Java classes.
This is achieved using JAXB xjc
The root class is TSDProductDataType and is further modeled as below:
The thing to note here is that ExtensionType contains protected List<Object> any; allowing it to store Objects of any class. In my case, it is amongst the classes named TSDModule_Name_HereModuleType and can be browsed here
Use spring-data-mongodb as persistence store
This is achieved using a simple ProductDataRepository
#RepositoryRestResource(collectionResourceRel = "product", path = "product")
public interface ProductDataRepository extends MongoRepository<TSDProductDataType, String> {
TSDProductDataType queryByGtin(#Param("gtin") String gtin);
}
The unmarshalled TSDProductDataType, however, contains JAXBElement which spring-data-mongodb doesn't seem to handle by itself and throws a CodecConfigurationException org.bson.codecs.configuration.CodecConfigurationException: Can't find a codec for class java.lang.Class.
Here is the faulty statement:
TSDProductDataType tsdProductDataType = jaxbElement.getValue();
repository.save(tsdProductDataType);
I tried playing around with Converters for spring-data-mongodb as explained here, however, it seems I am missing something since the exception is about "Codecs" and not "Converters".
Any help is appreciated.
EDIT:
Adding converters for JAXBElement
Note: Works with version 1.5.6.RELEASE of org.springframework.boot::spring-boot-starter-parent. With version 2.0.0.M3, hell breaks loose
It seems that I missed something while trying to add converter earlier. So, I added it like below for testing:
#Component
#ReadingConverter
public class JAXBElementReadConverter implements Converter<DBObject, JAXBElement> {
//#Autowired
//MongoConverter converter;
#Override
public JAXBElement convert(DBObject dbObject) {
Class declaredType, scope;
QName name = qNameFromString((String)dbObject.get("name"));
Object rawValue = dbObject.get("value");
try {
declaredType = Class.forName((String)dbObject.get("declaredType"));
} catch (ClassNotFoundException e) {
if (rawValue.getClass().isArray()) declaredType = List.class;
else declaredType = LinkedHashMap.class;
}
try {
scope = Class.forName((String) dbObject.get("scope"));
} catch (ClassNotFoundException e) {
scope = JAXBElement.GlobalScope.class;
}
//Object value = rawValue instanceof DBObject ? converter.read(declaredType, (DBObject) rawValue) : rawValue;
Object value = "TODO";
return new JAXBElement(name, declaredType, scope, value);
}
QName qNameFromString(String s) {
String[] parts = s.split("[{}]");
if (parts.length > 2) return new QName(parts[1], parts[2], parts[0]);
if (parts.length == 1) return new QName(parts[0]);
return new QName("undef");
}
}
#Component
#WritingConverter
public class JAXBElementWriteConverter implements Converter<JAXBElement, DBObject> {
//#Autowired
//MongoConverter converter;
#Override
public DBObject convert(JAXBElement jaxbElement) {
DBObject dbObject = new BasicDBObject();
dbObject.put("name", qNameToString(jaxbElement.getName()));
dbObject.put("declaredType", jaxbElement.getDeclaredType().getName());
dbObject.put("scope", jaxbElement.getScope().getCanonicalName());
//dbObject.put("value", converter.convertToMongoType(jaxbElement.getValue()));
dbObject.put("value", "TODO");
dbObject.put("_class", JAXBElement.class.getName());
return dbObject;
}
public String qNameToString(QName name) {
if (name.getNamespaceURI() == XMLConstants.NULL_NS_URI) return name.getLocalPart();
return name.getPrefix() + '{' + name.getNamespaceURI() + '}' + name.getLocalPart();
}
}
#SpringBootApplication
public class TsdApplication {
public static void main(String[] args) {
SpringApplication.run(TsdApplication.class, args);
}
#Bean
public CustomConversions customConversions() {
return new CustomConversions(Arrays.asList(
new JAXBElementReadConverter(),
new JAXBElementWriteConverter()
));
}
}
So far so good. However, how do I instantiate MongoConverter converter;?
MongoConverter is an interface so I guess I need an instantiable class adhering to this interface. Any suggestions?
I understand the desire for convenience in being able to just map an existing domain object to the database layer with no boilerplate, but even if you weren't having the JAXB class structure issue, I would still be recommending away from using it verbatim. Unless this is a simple one-off project, you almost definitely will hit a point where your domain models will need to change but your persisted data need to remain in an existing state. If you are just straight persisting the data, you have no mechanism to convert between a newer domain schema and an older persisted data scheme. Versioning of the persisted data scheme would be wise too.
The link you posted for writing the customer converters is one way to achieve this and fits in nicely with the Spring ecosystem. That method should also solve the issue you are experiencing (about the underlying messy JAXB data structure not converting cleanly).
Are you unable to get that method working? Ensure you are loading them into the Spring context with #Component plus auto-class scanning or manually via some Configuration class.
EDIT to address your EDIT:
Add the following to each of your converters:
private final MongoConverter converter;
public JAXBElement____Converter(MongoConverter converter) {
this.converter = converter;
}
Try changing your bean definition to:
#Bean
public CustomConversions customConversions(#Lazy MongoConverter converter) {
return new CustomConversions(Arrays.asList(
new JAXBElementReadConverter(converter),
new JAXBElementWriteConverter(converter)
));
}