理解mongodb Scala src中的隐式和订阅
我试图更好地理解Scala MongoDB src 使用scala mongodb驱动程序(api文档:) 当我使用理解mongodb Scala src中的隐式和订阅,mongodb,scala,Mongodb,Scala,我试图更好地理解Scala MongoDB src 使用scala mongodb驱动程序(api文档:) 当我使用 val collection: MongoCollection[Document] = database.getCollection("mycollection"); val observable: Observable[Completed] = collection.insertOne(doc) observable.subscribe(new
val collection: MongoCollection[Document] = database.getCollection("mycollection");
val observable: Observable[Completed] = collection.insertOne(doc)
observable.subscribe(new Observer[Completed] {
override def onNext(result: Completed): Unit = println("Inserted")
override def onError(e: Throwable): Unit = println("Failed")
override def onComplete(): Unit = println("Completed")
})
这是隐式方法吗
/**
* Subscribes to the [[Observable]] and requests `Long.MaxValue`.
*
* Uses the default or overridden `onNext`, `onError`, `onComplete` partial functions.
*
* @param doOnNext anonymous function to apply to each emitted element.
* @param doOnError anonymous function to apply if there is an error.
* @param doOnComplete anonymous function to apply on completion.
*/
def subscribe(doOnNext: T => Any, doOnError: Throwable => Any, doOnComplete: () => Any): Unit = {
observable.subscribe(new Observer[T] {
override def onSubscribe(subscription: Subscription): Unit = subscription.request(Long.MaxValue)
override def onNext(tResult: T): Unit = doOnNext(tResult)
override def onError(throwable: Throwable): Unit = doOnError(throwable)
override def onComplete(): Unit = doOnComplete()
})
}
src:
致电:
/**
* Request `Observable` to start streaming data.
*
* This is a "factory method" and can be called multiple times, each time starting a new [[Subscription]].
* Each `Subscription` will work for only a single [[Observer]].
*
* If the `Observable` rejects the subscription attempt or otherwise fails it will signal the error via [[Observer.onError]].
*
* @param observer the `Observer` that will consume signals from this `Observable`
*/
def subscribe(observer: Observer[_ >: T]): Unit
src:
似乎调用subscribe调用了一个新线程(它被称为subscribe),但我看不出这个新线程是从src调用的
隐式连接用于实现这种“连接”,当我使用observable.subscribe时,它调用隐式subscribe方法(newobservator[Completed]{..
更新:
使用此代码:
import org.mongodb.scala.MongoClient;
import org.mongodb.scala.bson.collection.immutable.Document;
import org.mongodb.scala._
import org.scalatest._
import Matchers._
import org.mongodb.scala._
class MongoSpec extends FlatSpec with Matchers {
"Test MongoDb" should "insert" in {
{
val mongoClient: MongoClient = MongoClient()
val database: MongoDatabase = mongoClient.getDatabase("scala-poc");
val doc: Document = Document("_id" -> 6, "name" -> "MongoDB", "type" -> "database",
"count" -> 1, "info" -> Document("x" -> 203, "y" -> 100))
val collection: MongoCollection[Document] = database.getCollection("documents");
val observable: Observable[Completed] = collection.insertOne(doc)
observable.subscribe(new Observer[Completed] {
override def onNext(result: Completed): Unit = println("Inserted")
override def onError(e: Throwable): Unit = println(" \n\nFailed " + e + "\n\n")
override def onComplete(): Unit = println("Completed")
})
mongoClient.close();
}
}
}
导致以下异常的原因:
Failed com.mongodb.MongoClientException: Shutdown in progress
在insertOne方法完成之前,正在调用mongoClient.close()
那么insertOne或subscribe方法是异步的
subscribe(doOnNext,doOnError,doOnComplete)
调用subscribe(observer)
(正如您在问题中引用的实现所示)。因此,如果也从那里调用它,您将得到一个无限循环。当您编写类似observer.subscribe(x=>println(s“next=$x”)的内容时,将使用“连线”,error=>error.printStackTrace(),()=>{})
subscribe
不会创建新线程。实现Observable
的类主要从Java MongoDB驱动程序包装类,并调用它们自己的subscribe
方法,例如,这些subscribe
方法也不会启动新线程:请参阅以获取一些解释subscribe(doOnNext,doOnError,doOnComplete)
调用subscribe(observer)
(正如您在问题中引用的实现所示)。因此,如果也从那里调用它,您将得到一个无限循环。当您编写类似observer.subscribe(x=>println(s“next=$x”)的内容时,将使用“连线”,error=>error.printStackTrace(),()=>{})
subscribe
不会创建新线程。实现Observable
的类主要从Java MongoDB驱动程序包装类,并调用它们自己的subscribe
方法,例如,这些subscribe
方法也不会启动新线程:请参阅以获取一些解释请参阅更新,似乎发生了异步操作,我不确定在何处。请参阅更新,似乎发生了异步操作,我不确定在何处。为此,您应该查看Java驱动程序源代码,而不是Scala,它是一个简单的包装器。当然,
insertOne
是异步的,因为Scala驱动程序使用的是异步Java驱动程序。为此,您应该查看Java驱动程序源代码,而不是Scala,它是一个简单的包装器。但是当然,insertOne
是异步的,因为Scala驱动程序使用的是异步Java驱动程序。