README.md

Functional Rosetta Stone

Goal

A repository to review the main concepts about Functional Programming with Java.

How to build the project in local?

sdk env install
./mvnw clean test -DexcludedGroups=performance,endtoend
./mvnw clean test -DexcludedGroups=performance,endtoend -pl training
./mvnw clean test -DexcludedGroups=performance,endtoend -Dtest=EitherTest -pl training
./mvnw clean compile exec:java -Dexec.mainClass="info.jab.fp.concepts.FunctionalCompositionExamples" -Dexec.args="--enable-preview" -pl training
./mvnw clean test -Dgroups=performance
./mvnw clean test -Dgroups=endtoend

./mvnw versions:display-property-updates
./mvnw versions:display-dependency-updates
./mvnw versions:display-plugin-updates
./mvnw dependency:tree -pl problems 

Functional programming features in Java

• Lambda Expressions (Functional interfaces, Functions, Supplier, Consumer & Predicates)
• Optional
• Stream API & Gatherers
• CompletableFuture & Structural Concurrency
• Immutable Lists
• Sealed Classes
• Pattern Matching for Switch
• Records & Record Patterns

Functional programming features

• Equational Reasoning
• Pure/Impure functions
• Referential Transparency
• Immutability
• Functional composition
• Eager vs Lazy

How to run the presentation in local?

jwebserver -p 9000 -d "$(pwd)/docs/"

Performance

Using the jmh-results.json you can review the performance results:

• https://jmh.morethan.io/
• https://nilskp.github.io/jmh-charts/
• https://github.com/akarnokd/jmh-compare-gui

References

• https://github.com/jabrena/latency-problems
• https://github.com/forax/loom-fiber
• https://cr.openjdk.org/~vklang/Gatherers.html
• https://github.com/forax/we_are_all_to_gather
• https://www.infoq.com/articles/data-oriented-programming-java/
• https://inside.java/2024/05/23/dop-v1-1-introduction/
• https://inside.java/2024/05/27/dop-v1-1-immutable-transparent-data/
• https://inside.java/2024/05/29/dop-v1-1-model-data/