Skip to main content

Book: Functional Programming for Java Developers: Tools for Better Concurrency, Abstraction, and Agility

Probably all of us forget functional programming in the name of object oriented one. As concurrency and scalability are two buzzwords mentioned these days in every technical acrticle the functional programming notion seems to growing.

The book Functional Programming for Java Developers: Tools for Better Concurrency, Abstraction, and Agility is brief introduction why and how could developer or architect think about development, especialy in the scope of reusable components.

The couple of chapters at the beggining show how functional programming approach can improve thinking of every programmer. Special attention is put on objects immutability or functional recursion.

Next chapters present the example how to write immutable list and maps, how to write useful methods operating above the list using recursion and how to use these methods for everything what you can want from the structure.

Well, I read the book twice. The impact was immediate since I was writting a component based on tree structure. As soon as you realize the immutability is better than classic locking-aware approach you start asking how to achieve such pleasat property on objects requiring mutability by nature. It requires the change of mind. This book can help you a lot.


Popular posts from this blog

Performance Battle of NoSQL blob storages #1: Cassandra

Preface We spend last five years on HP Service Virtualization using MsSQL database . Non-clustered server. Our app utilizes this system for all kinds of persistence. No polyglot so far. As we tuned the performance of the response time - we started at 700ms/call and we achieved couple milliseconds per call at the end when DB involved - we had to learn a lot of stuff. Transactions, lock escalation , isolation levels , clustered and non clustered indexes, buffered reading, index structure and it's persistence, GUID ids in clustered indexes , bulk importing , omit slow joins, sparse indexes, and so on. We also rewrite part of NHibernate to support multiple tables for one entity type which allows use scaling up without lock escalation. It was good time. The end also showed us that famous Oracle has half of our favorite features once we decided to support this database. Well, as I'm thinking about all issues which we encountered during the development, unpredictive behavio

NHibernate performance issues #3: slow inserts (stateless session)

The whole series of NHibernate performance issues isn't about simple use-cases. If you develop small app, such as simple website, you don't need to care about performance. But if you design and develop huge application and once you have decided to use NHibernate you'll solve various sort of issue. For today the use-case is obvious: how to insert many entities into the database as fast as possible? Why I'm taking about previous stuff? The are a lot of articles how the original NHibernate's purpose isn't to support batch operations , like inserts. Once you have decided to NHibernate, you have to solve this issue. Slow insertion The basic way how to insert mapped entity into database is: SessionFactory.GetCurrentSession().Save(object); But what happen when I try to insert many entities? Lets say, I want to persist 1000 libraries each library has 100 books = 100k of books each book has 5 rentals - there are 500k of rentals  It's really slow! The inser

Jenkins + git revision in all build names

Jenkins by default assigns version of a build using local counter within each type of a build. An example is better. When you look at this overview, you definitely do not know which code revision was used in Compile build and which in Integration Tests . I've followed nice article regarding real CI pipeline using jenkin s. It uses Build Name Setter Plugin. Unfortunately this article uses SVN revision number. So I said I'll just use git revision as git is my source control. But it's not so easy as how it could seem for first look. My Jenkins setup comprised of first compile build step which clones git server and performs an compilation. Second build steps clones the repository from first step and executes integration tests . The problem here is that the second step does not know which git revision compile step cloned. Here is list of steps how to do that. 1. You obviously need Git Plugin , Build Name Setter Plugin and Parameterized Trigger Plugin 2. Compile