ZooKeeper wrapper written in Scala

Shelves

package com.klout.playful2.zookeeper

import com.twitter.zookeeper.ZooKeeperClient
import org.apache.zookeeper.CreateMode
import com.klout.playful2.sugar.{ config, please }

/**
* This is a simple library to add, set, delete and watch ZooKeeper nodes
*
* @author Felipe Oliveira [@_felipera]
*/
object Shelves {

   /**
    * Location of the ZK server(s)
    */
   lazy val hosts = config string "zookeeper.hosts" !
   lazy val zk = new ZooKeeperClient(hosts)

   /**
    * This is gonna create a new node on ZooKeeper
    */
   def add(path: String, value: String, createMode: CreateMode) = zk create (path, value.getBytes, createMode)

   /**
    * This is gonna update the value of a node on ZooKeeper
    */
   def set(path: String, value: String) = zk set (path, value.getBytes)

   /**
    * Deletes a node on ZooKeeper
    */
   def delete(path: String) = zk delete path

   /**
    * Gets the value of the node
    */
   def get(path: String) = zk get path

   /**
    * Callback
    */
   def on(path: String)(runnable: NodeStatusChange => Unit) = {
       zk watchNode (path, {
           (data: Option[Array[Byte]]) =>
               data match {
                   case Some(d) if d.isEmpty =>
                       please log "Node [%s] changed to be empty".format(path)
                       runnable(NodeUpdated(None))
                   case Some(d) =>
                       val value = new String(d)
                       please log "Node [%s] updated: %s".format(path, value)
                       runnable(NodeUpdated(Option(value)))
                   case None =>
                       please log "Node [%s] deleted!".format(path)
                       runnable(NodeDeleted)
               }
       })
   }
}

sealed trait NodeStatusChange
case object NodeDeleted extends NodeStatusChange
case class NodeUpdated(maybeValue: Option[String]) extends NodeStatusChange