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Scala

Neo4j: The BBC Champions League graph

A couple of weekends ago I started scraping the BBC live text feed of the Bayern Munich/Barcelona match, initially starting out with just the fouls and building the foul graph. I’ve spent a bit more time on it since then and have managed to model several other events as well including attempts, goals, cards and free kicks. I started doing ...

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Akka samples with scala and Spring

I was looking around recently for Akka samples with Spring and found a starter project which appeared to fit the bill well. The project however utilizes Spring-Scala which is an excellent project, but is no longer maintained. So I wanted to update the sample to use core Spring java libraries instead. So here is an attempt on a fork of ...

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The Bet With Typesafe That Got Me Into Building Akka

Back to the drawing board: The lost lines of code on the road to Akka Streams, Akka HTTP and Akka Typed If you’ve ever been curious about how new core features are being developed and why your favorite technologies take on a certain path, you’ve reached the right place. In the new design decisions series on the Takipi blog you’ll ...

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Scala Snippet: How to filter a list in Scala

In Scala, filtering and processing collections is easy and elegant. There are many filtermethods available, but the most used will probably the basic filter method. Here’s a code example of some filtering on my (ex)camera collection. The filter method will not only work on Lists, but on any Scala collection. object MyCameraCollection02 { class Camera(_brand: String, _model: String, _sensorType: String, ...

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Spark: Generating CSV files to import into Neo4j

About a year ago Ian pointed me at a Chicago Crime data set which seemed like a good fit for Neo4j and after much procrastination I’ve finally got around to importing it. The data set covers crimes committed from 2001 until now. It contains around 4 million crimes and meta data around those crimes such as the location, type of ...

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Scala Snippet: Object, Companion Object and Static Methods

If you are a Java developer moving to Scala, one notable difference in terminology that can cause confusion is the term ‘object’. In Java an object is always an instance of a class, created by calling a constructor. Object In Scala an object is used for defining a single instance of a class with the features you want. In practice ...

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Scala Snippet: Case Class vs plain ordinary Class

In Scala there exist the construct of a ‘case class’. According to Martin Odersky this supports you to write a “regular, non-encapsulated data structure”. It always seems to be associated with pattern matching. So when to use a case class and when to use a ‘plain’ class? I found this nice explanation stating: “Case classes can be seen as plain ...

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Alternating between Spray-servlet and Spray-can

On a server you may want to deploy your application as a war. How to build a war with spray-servlet. Locally it’s easiest to run without an application server. We include both the spray-servlet and spray-can dependencies: name := "sprayApiExample" version := "1.0" scalaVersion := "2.11.6" libraryDependencies ++= { val akkaV = "2.3.9" val sprayV = "1.3.3" Seq( "io.spray" %% ...

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Building a war with spray-servlet

We will use spray-servlet to build a war file of our API. So we can run it in a java app server. I assume we already have a working REST API. We will need a web.xml, under src/main/webapp/WEB-INF/: <?xml version="1.0"?> <web-app> <listener> <listener-class>spray.servlet.Initializer</listener-class> </listener> <servlet> <servlet-name>SprayConnectorServlet</servlet-name> <servlet-class>spray.servlet.Servlet30ConnectorServlet</servlet-class> <async-supported>true</async-supported> </servlet> <servlet-mapping> <servlet-name>SprayConnectorServlet</servlet-name> <url-pattern>/*</url-pattern> </servlet-mapping> </web-app> We need an sbt plugin to ...

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