com.twitter.zk.AsyncCallbackPromise.scala Maven / Gradle / Ivy

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package com.twitter.zk

import java.util.{List => JList}

import scala.collection.JavaConverters._

import org.apache.zookeeper.data.Stat
import org.apache.zookeeper.{AsyncCallback, KeeperException}

import com.twitter.util.{Promise, Return, Throw}

/** Mix-in to make an AsyncCallback a Promise */
trait AsyncCallbackPromise[T] extends Promise[T] {
  /** Process result iff rc is OK; otherwise throw a KeeperException. */
  protected def process(rc: Int, path: String)(result: => T) {
    KeeperException.Code.get(rc) match {
      case KeeperException.Code.OK => updateIfEmpty(Return(result))
      case code => updateIfEmpty(Throw(KeeperException.create(code, path)))
    }
  }
}

class StringCallbackPromise extends AsyncCallbackPromise[String] with AsyncCallback.StringCallback {
  def processResult(rc: Int, path: String, ctx: AnyRef, name: String) {
    process(rc, path) { name }
  }
}

class UnitCallbackPromise extends AsyncCallbackPromise[Unit] with AsyncCallback.VoidCallback {
  def processResult(rc: Int, path: String, ctx: AnyRef) {
    process(rc, path) { Unit }
  }
}

class ExistsCallbackPromise(znode: ZNode) extends AsyncCallbackPromise[ZNode.Exists]
    with AsyncCallback.StatCallback {
  def processResult(rc: Int, path: String, ctx: AnyRef, stat: Stat) {
    process(rc, path) {
      znode(stat)
    }
  }
}

class ChildrenCallbackPromise(znode: ZNode) extends AsyncCallbackPromise[ZNode.Children]
    with AsyncCallback.Children2Callback {
  def processResult(rc: Int, path: String, ctx: AnyRef, children: JList[String], stat: Stat) {
    process(rc, path) {
      znode(stat, children.asScala.toSeq)
    }
  }
}

class DataCallbackPromise(znode: ZNode) extends AsyncCallbackPromise[ZNode.Data]
    with AsyncCallback.DataCallback {
  def processResult(rc: Int, path: String, ctx: AnyRef, bytes: Array[Byte], stat: Stat) {
    process(rc, path) {
      znode(stat, bytes)
    }
  }
}