So, @rotnroll666 nerd sniped me again. Apparently, the Neo4j Cypher query language supports arbitrary reductions, just like any functional collection API, oh say, the JDK Stream API: Stream.of(2, 4, 3, 1, 6, 5) .reduce((i, j) -> i * j) .ifPresent(System.out::println); // Prints 720 SQL doesn't have this, yet it would be very useful to be … Continue reading Implementing a generic REDUCE aggregate function with SQL
Tag: Functional Programming
Lesser Known jOOλ Features: Useful Collectors
jOOλ is our second most popular library. It implements a set of useful extensions to the JDK's Stream API, which are useful especially when streams are sequential only, which according to our assumptions is how most people use streams in Java. Such extensions include: // (1, 2, 3, 1, 2, 3, 1, 2, 3, 1, … Continue reading Lesser Known jOOλ Features: Useful Collectors
Imperative Loop or Functional Stream Pipeline? Beware of the Performance Impact!
I like weird, yet concise language constructs and API usages https://twitter.com/nipafx/status/1055451667079008256 Yes. I am guilty. Evil? Don't know. But guilty. I heavily use and abuse the java.lang.Boolean type to implement three valued logic in Java: Boolean.TRUE means true (duh) Boolean.FALSE means false null can mean anything like "unknown" or "uninitialised", etc. I know - a … Continue reading Imperative Loop or Functional Stream Pipeline? Beware of the Performance Impact!
A Nice API Design Gem: Strategy Pattern With Lambdas
With Java 8 lambdas being available to us as a programming tool, there is a "new" and elegant way of constructing objects. I put "new" in quotes, because it's not new. It used to be called the strategy pattern, but as I've written on this blog before, many GoF patterns will no longer be implemented … Continue reading A Nice API Design Gem: Strategy Pattern With Lambdas
jOOQ Tuesdays: Mario Fusco Talks About Functional and Declarative Programming
Welcome to the jOOQ Tuesdays series. In this series, we’ll publish an article on the third Tuesday every other month where we interview someone we find exciting in our industry from a jOOQ perspective. This includes people who work with SQL, Java, Open Source, and a variety of other related topics. I'm very excited to … Continue reading jOOQ Tuesdays: Mario Fusco Talks About Functional and Declarative Programming
jOOQ Tuesdays: Daniel Dietrich Explains the Benefits of Object-Functional Programming
Welcome to the jOOQ Tuesdays series. In this series, we’ll publish an article on the third Tuesday every other month where we interview someone we find exciting in our industry from a jOOQ perspective. This includes people who work with SQL, Java, Open Source, and a variety of other related topics. I'm very excited to … Continue reading jOOQ Tuesdays: Daniel Dietrich Explains the Benefits of Object-Functional Programming
How Functional Programming will (Finally) do Away With the GoF Patterns
A recent article about various ways to implement structural pattern matching in Java has triggered my interest: http://blog.higher-order.com/blog/2009/08/21/structural-pattern-matching-in-java The article mentions a Scala example where a tree data structure can be traversed very easily and neatly using Scala's match keyword, along with using algebraic data types (more specifically, a sum type): def depth(t: Tree): Int … Continue reading How Functional Programming will (Finally) do Away With the GoF Patterns
10 Easy Steps to a Complete Understanding of SQL
Too many programmers think SQL is a bit of a beast. It is one of the few declarative languages out there, and as such, behaves in an entirely different way from imperative, object-oriented, or even functional languages (although, some say that SQL is also somewhat functional). As a SQL trainer (do visit our training, it's … Continue reading 10 Easy Steps to a Complete Understanding of SQL
Beware of Functional Programming in Java!
This isn't going to be a rant about functional programming, which is awesome. This is a warning about some practices that you are very likely going to apply to your code, which are terribly wrong!. Higher order functions are essential to functional programming, and thus, talking about them will help you be the center of … Continue reading Beware of Functional Programming in Java!
The Danger of Subtype Polymorphism Applied to Tuples
Java 8 has lambdas and streams, but no tuples, which is a shame. This is why we have implemented tuples in jOOλ - Java 8's missing parts. Tuples are really boring value type containers. Essentially, they're just an enumeration of types like these: public class Tuple2<T1, T2> { public final T1 v1; public final T2 … Continue reading The Danger of Subtype Polymorphism Applied to Tuples