In this article I am going to present some of the most useful Scala libraries and frameworks which help ASSIST Software engineers to develop highly scalable applications that support concurrency and non-blocking.

1. Published on ASSIST Software (http://assist-software.net)
Home > Awesome Scala
Awesome Scala
Awesome Scala
Submitted on Fri, 19 Sep 2014 by Lucian NEGHIN? in Projects Channel
Contents
Intro
What is and why Scala
Web Frameworks
Play
Spray
Lift
Other great scala web frameworks
Database
Slick
Squeryl
Activate
Salat
ReactiveMongo
JSON Manipulation
Spray-json
Jackson-module-scala
Json4s
Testing
Specs2
ScalaTest
Scalastyle
Metrics and Monitoring
Kamon
Intro
In this article I am going to present some of the most useful Scala libraries and frameworks which help
ASSIST Software
engineers to develop highly scalable applications that support concurrency and non-blocking.
What is and why Scala
Scala is a programming language for the Java Virtual Machine (JVM) that integrates features of both

2. object-oriented and functional programming. Scala provides a best-of-all-worlds experience for developers,
it?s compatible with classic Java libraries and it?s designed to express common programming patterns in a
concise and elegant way. But most important: Scala provides a type-safe language with powerful
concurrency on top of a mature ecosystem.
Web Frameworks
There are lots of Scala frameworks which you can use to develop web applications quickly and easily, but I
mostly
will present the ones which are
used:
Play
Play is the official Scala framework supported by Typesafe Inc., creator of the Scala programming
language. Play is a modern web framework which combines productivity and performance making it easy
to build scalable applications. This framework is ideal for developers who are more familiar with the MVC
architecture.
Spray
Spray is not a framework, it's a suite of lightweight and very fast Scala libraries designed to build RESTful
web services on top of Akka. With Spray you can develop standalone service based on spray-can module
which provides a low-level, low-overhead and high-performance HTTP server and client. You can also
develop a web service which runs inside a Jetty server.
Using Spray together with a JavaScript framework like AngularJS, jQuery, Backbone or many others, you
can approach the new trend of the web applications by moving the business logic from the server into the
client side.
Lift
Lift is another popular, secure and powerful full stack web framework for scala. Lift is based on a View First
approach as opposed to the typical MVC architecture, that means it divides web components into snippets,
not in pages. The big plus of this framework is the native JavaScript/Ajax support, which offers an easy
way to develop complex interactive web pages.

3. Other great scala web frameworks
Scalatra
Scalatra is an easy to understand micro-framework and a great option if you want to build lightweight and
simple applications. Scalatra is inspired by Sinatra which is a Ruby framework.
Finatra
Finatra is another async web framework inspired by Sinatra, but this one runs on top of Finagle, a RPC
System created by Twitter.
BlueEyes
BlueEyes is a purely asynchronous, extremely high-performance framework, intended only to create
RESTful web services.
Database
In this section I will present a few scala libraries that allow you to access SQL databases like MySQL or
PostgreSQL, but also NoSQL databases like MongoDB.
Slick
Slick is an easy, scalable, concise, safe, compositional and mature database query and access library for
Scala. Slick tries to make queries use the same for comprehension as Scala collections do. It?s supported
by Typesafe Inc. and can be used only on the following databases systems: H2, MySQL, PostgreSQL,
SQLite, Derby/JavaDB, Microsoft Access, HSQLDB/HyperSQL.
Slick is to Hibernate and JDBC, what Scala is to Java and Groovy.
Squeryl
Squeryl is an ORM which is completely type-safe and the queries are written in a DSL that is close to SQL.
This library allows you to explicitly control the granularity of data objects that are retrieved while it provides
an elegant solution to the N+1 queries problem.
Squeryl is more like Hibernate.
Activate
Activate is a great scala framework to persist objects in different paradigms such as relational, prevalence
and non-relational. It?s designed to be simple and uses Software Transactional Memory, which is a
concurrency control mechanism to handle with transactions in-memory, without needing to use
transactional control from the storage.
Activate is the best choice for applications with concurrent bank transactions.
Salat
Salat is an ORM for MongoDB which provides fast, simple, bidirectional serialization between Scala Case

4. Classes and DBObject. Salat is based in Casbah, the official MongoDB driver and because of that Salat
has the following restrictions:
can?t support nested inner classes
doesn?t use a class type at the top-level to a trait or an abstract superclass
any type of Map must have String key only which do not contain ?.?or ?$?
Salat is the most used MongoDB persistent library.
ReactiveMongo
ReactiveMongo is an asynchronous, non-blocking Scala driver for MongoDB. In a classic synchronous
driver like Casbah, each operation blocks the current thread until a response is received and that can be a
problem if you have an application with multiple concurrent accesses to the database.
ReactiveMongo is young, but mature enough to be used in production.
JSON Manipulation
Spray-json
Spray-json is a lightweight, clean and efficient JSON implementation in Scala and is based on the
parboiled parsing library. Considering the deserialization time, spray-json is nor the fastest library, neither
the slowest. Another negative aspect is the limit to parsing json data with more than 22 fields. This limit is
because spray-json is based on Tuples, where the maxim type is Tuple22. However spray-json is a very
used library because it offers an easy way to manipulate entities from/to JSON.
Jackson-module-scala
Jackson-module-scala is the fastest JSON parser and is the official Scala support module for Jackson
(Java library). You can also use the java library in your scala project and will obtain the same performance,
but by using jackson-module-scala you will have support to serialization and deserialization of scala Case
Classes, Sequences, Maps, Tuples, Options and Enumerations.
Json4s
Json4s is a very promising project where the aim is to provide a single AST to be used by other Scala
JSON libraries. Json4s has an extremely rich functional API and supports multiple backends like Lift JSON
or Jackson and has native support from Spray and Scalatra.
Testing
Specs2
Specs2 is an open source library based on specifications. Specs2 supports unit testing for one class (unit
specifications) and acceptance testing for the full-system (acceptance specifications). The specs2 tests are
asynchronous and each runs in its thread using a Promise, that?s why it works well with Akka.
ScalaTest

5. ScalaTest is another great testing library which can be used to do unit tests, functional tests, performance
test. ScalaTest offers deep integration with tools like JUnit, Mockito, ScalaCheck, Selenium, ScalaCheck
and supports TDD (Test Driven Development), BDD (Behavior Driven Development) and acceptance
testing.
Scalastyle
Scalastyle is a scala style checker which examines your code and indicates where you are not respected
the grammar or the functional programming principles in Scala. It can be integrated with Intellij or Eclipse,
but also it can be used with SBT, Maven, Gradle.
Metrics and Monitoring
Kamon
Kamon is a set of tools that help you to get metrics from your applications built with Spray, Akka or Play.
Kamon offers support to be integrated with other backend services like StatsD and Graphite which are free
but it can also be integrated with New Relic.
Source URL: http://assist-software.net/blog/awesome-scala