The jOOQ API is all about convenience, and as such, an important operation (the most important one?) like fetch() must come with convenience, too. The default way to fetch data is this: Result<Record1<String>> result = ctx.select(BOOK.TITLE) .from(BOOK) .fetch(); for (Record1<String> record : result) { // ... } It fetches the entire result set into memory … Continue reading The Many Different Ways to Fetch Data in jOOQ
Category: jooλ
Use jOOλ’s Sneaky Throw to Avoid Checked Exceptions
Don't you hate how you have to wrap checked exception throwing code in static initialisers? E.g. you cannot write this in Java: public class Test { static final Class<?> klass = Class.forName("org.h2.Driver"); } There's an unhandled ClassNotFoundException, and you can't catch / rethrow it simply. A static initialiser is needed: public class Test { static … Continue reading Use jOOλ’s Sneaky Throw to Avoid Checked Exceptions
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
An Ingenious Workaround to Emulate an Application of Union Types in Java
Before I move on with the actual article, I'd like to give credit to Daniel Dietrich, author of the awesome vavr library, who has had the idea before me: https://twitter.com/danieldietrich/status/699633269202149377 Contravariant Generic Bounds It all started with a tweet: https://twitter.com/lukaseder/status/699588908095508480 I wanted to do something like pattern-matching a common super type of a set of … Continue reading An Ingenious Workaround to Emulate an Application of Union Types in Java
How to Pattern-Match Files and Display Adjacent Lines in Java
Recently, we've published our article about the awesome window function support in jOOλ 0.9.9, which I believe is some of the best additions to the library that we've ever done. Today, we'll look into an awesome application of window functions in a use-case that is inspired by this Stack Overflow question Sean Nguyen: How to … Continue reading How to Pattern-Match Files and Display Adjacent Lines in Java
2016 Will be the Year Remembered as When Java Finally Had Window Functions!
You heard right. Up until now, the awesome window functions were a feature uniquely reserved to SQL. Even sophisticated functional programming languages still seem to lack this beautiful functionality (correct me if I'm wrong, Haskell folks). We've written tons of blog posts about window functions, evangelising them to our audience, in articles like: Probably the … Continue reading 2016 Will be the Year Remembered as When Java Finally Had Window Functions!
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