#SCALA FUTURE HOW TO#
#SCALA FUTURE DRIVER#

In the UNIX world you can request the -p (parent) flag to the mkdir command to ensure parent directories get created. You can't create path '/foo/bar' is path '/foo' doesn't exist. ZNode path addresses work just like UNIX paths.

#SCALA FUTURE HOW TO#

Now that you know how to get information out of zookeeper. This is useful due to the fact that getting the children of a given znode defines ( (, boolean)) about the order in which they are returned. Println( s ' node has $ children ')Īn instance of Ordering is defined for ZNodes which accounts for sequential names.

installĪdd the following to your sbt build definitionĬase children => // children is a znode ref populated with the nodes stored at its path Zoey splits up this interface in a way that makes ZNodes, a core zookeeper abstraction, a first class citizen in zoey's client interface.

#SCALA FUTURE DRIVER#

The standard java zookeeper driver defines one entry point, the client, which defines a number of methods for both managing a session's connection state and performing operations on paths. model interfaces more closely to the domain.Generally, the result of the Future is computed concurrently and can be later collected. The idea is simple, a Future is a sort of a placeholder object that you can create for a result that does not yet exist. Scala's standard library Futures model latter very well providing a familiar interface that works well with existing scala libraries. Scalas Futures API Futures provide a nice way to reason about performing many operations in parallel in an efficient and non-blocking way. The standard java zookeeper driver supports blocking operations with an optional support for callback style async operations. As a result, the users of future.

Also, there is no isComplete method in our futures. Instead, future.scala evaluate lazily, and they do the same job every time you invoke onComplete. These zookeeper interfaces should be designed with that in mind. future.scala are pure functional, thus they will never store result values or exceptions. The tradeoff is that it gives you powerful tools at the cost of a slig. Despite that, networks are still unreliable. Answer (1 of 37): TL DR: Learning Scala and the mix of OOP and FP that comes with it, will not only help you write better code, but it will also enable you to solve the more difficult problems at a higher level of abstraction. Zookeeper is a mature HA answer for many distributed systems questions. Interacting with the standard java driver is not. def zipWith U, R ( that: Future U) ( f: ( T, U) R) ( implicit executor: ExecutionContext): Future R Zips the values of this and that future using a function f, and creates a new future holding the result. The underlying concepts of zookeeper are simple. a Future with the results of both futures or the failure of the first of them that failed. Inspired by Twitter's wonderful zk-client, implemented in terms of scala's standard library features.

A non-blocking interface for apache zookeeper.

Scala future