How to build a Spring + Hibernate + gRPC application

                

import com.google.protobuf.Empty
import com.the.sample.app.grpc.UserServiceEndpointGrpc.UserServiceEndpointImplBase
import com.the.sample.app.grpc.UserServiceEndpointOuterClass.*
import com.the.sample.app.model.User
import com.the.sample.app.service.UserService
import io.grpc.stub.StreamObserver
import org.lognet.springboot.grpc.GRpcService
import java.util.*

@GRpcService
class UserServiceEndpointImpl(val userService: UserService) : UserServiceEndpointImplBase() {
    override fun findById(request: UserByIdRequest, responseObserver: StreamObserver) {
        val userDto: UserDto? = Optional.ofNullable(request).
            map { request: UserByIdRequest -> request.id }.
            map { id: Long -> userService.findById(id) }.
            flatMap { res-> Optional.ofNullable(res).map { userData: User ->
            UserDto.newBuilder().setEmail(userData.email).setFullName(userData.fullName).build() } }.
            orElse(null)
        responseObserver.onNext(UserResponse.newBuilder().setUser(userDto).build())
        responseObserver.onCompleted()
    }

    override fun findByEmail(request: UserByEmailRequest, responseObserver: StreamObserver) {
        val userDto: UserDto? = Optional.ofNullable(request).
            map { request: UserByEmailRequest -> request.email }.
            map { email: String -> userService.findByEmail(email) }.
            flatMap { res-> Optional.ofNullable(res).map { userData: User ->
                UserDto.newBuilder().setEmail(userData.email).setFullName(userData.fullName).build() } }.
            orElse(null)
        responseObserver.onNext(UserResponse.newBuilder().setUser(userDto).build())
        responseObserver.onCompleted()
    }

    override fun save(request: CreateUserRequest, responseObserver: StreamObserver) {
        Optional.ofNullable(request).ifPresent { req: CreateUserRequest ->
            userService!!.save(
                User(email = req.email, fullName = req.fullName)
            )
        }
        responseObserver.onNext(Empty.newBuilder().build())
        responseObserver.onCompleted()
    }

    override fun update(request: UpdateUserRequest?, responseObserver: StreamObserver) {
        Optional.ofNullable(request).ifPresent { req: UpdateUserRequest ->
            userService!!.save(
                User(id = req.id,
                    email = req.email,
                    fullName = req.fullName)
            )
        }
        responseObserver.onNext(Empty.newBuilder().build())
        responseObserver.onCompleted()
    }

    override fun deleteById(request: UserByIdRequest, responseObserver: StreamObserver) {
        Optional.ofNullable(request).map { obj: UserByIdRequest -> obj.id }.ifPresent { id: Long? ->
            userService!!.deleteById(
                id!!
            )
        }
        responseObserver.onNext(Empty.newBuilder().build())
        responseObserver.onCompleted()
    }
}

                    
                
            

                

import com.the.sample.app.model.User
import com.google.protobuf.empty.Empty
import com.the.sample.app.grpc.UserServiceEndpoint.{CreateUserRequest, UpdateUserRequest, UserByEmailRequest, UserByIdRequest, UserDto, UserResponse, UserServiceEndpointGrpc}
import com.the.sample.app.service.UserService
import org.lognet.springboot.grpc.GRpcService

import scala.concurrent.Future
@GRpcService
class UserServiceEndpointImpl(val userService: UserService) extends UserServiceEndpointGrpc.UserServiceEndpoint{
  override def findById(request: UserByIdRequest): Future[UserResponse] =
    Future.successful(UserResponse(user = Option(request).map(_.id).
      flatMap(userService.findById(_)).map(user=>
      UserDto(id = user.id,
        email = user.email,
        fullName = user.fullName))))


  override def findByEmail(request: UserByEmailRequest): Future[UserResponse] =
    Future.successful(UserResponse(user = Option(request).map(_.email).
      flatMap(userService.findByEmail(_)).map(user=>
      UserDto(id = user.id,
        email = user.email,
        fullName = user.fullName))))

  override def save(request: CreateUserRequest): Future[Empty] = {
    Option(request).
      map(req=>new User(req.email,req.fullName)).
        foreach(userService.save(_))
    Future.successful(Empty.defaultInstance)
  }

  override def update(request: UpdateUserRequest): Future[Empty] = {
    Option(request).
      map(req=>{
        val user = new User(req.email,req.fullName)
        user.id = req.id
        user
      }).
      foreach(userService.save(_))
    Future.successful(Empty.defaultInstance)
  }

  override def deleteById(request: UserByIdRequest): Future[Empty] = {
    Option(request).
      map(_.id).
      foreach(userService.deleteById(_))
    Future.successful(Empty.defaultInstance)
  }
}