Wednesday, June 25, 2014

When fast is merely not good enough

In the pursuit of applications that are having ever increasing speeds, I am constantly looking around for new ideas and have come across an interesting term, reactive programming that addresses a lot of concepts and puts the possible answer into a single umbrella; or quite simply speaking, gives it a name.
Basically, any web application under this umbrella term is people first - meaning it will inform its client what is happening instead of a delayed page load that can take anywhere between 2 seconds and hours. It always provides a real-time response to the client and responds to clients, events, load and failure.

This is typically done by making the application use following characteristics:
  1. Responsive
  2. Scalable
  3. Resilient
  4. Event-Driven

When these applications are cohesively applied, the common pattern/word that emerges gets labelled under the term reactive programming, which is promised by the

Thursday, June 5, 2014

Book Review: Client Server Web Apps with Javascript and Java

The book, 'Client server Web Apps with Javascript and Java' by Casimir Saternos aply provides its puchline, 'Rich, Scalable and Restful'. These words do not only cover the essence of this book, but also describe the adoption of Javascript based frameworks and technologies on the user-interface/frontend of today's Enterprise Java applications.

A new term is used to introduce the users - Client-Server, which signifies that client side of an application is as important as its server side and the amount of programming efforts required on the client side is also as big as it is managed on the server. It is similar to the other topics that are introduced in this book - completely from scratch, which enforce learning familiar concepts like JavaScript refreshing to learn.
Even for an experienced developer, there are lot of things to watch out for like in chapter 2 where excerpts from 'Javascript: The Good Part' by Douglas Crockford are cited for concise learning. Similarly, in the next chapter detailing REST and JSON, the non-existence of url/syndication in JSON and its related debate surrounding HATEOAS (Hypermedia As The Engine Of Application State) is explained. The JVM specific languages are mentioned by highlighting build tools related to them, which is potentially confusing if the person reading is not familiar with build, version and test tools.
The next part of the book starting with Chapter 5 deals with the client side web application and quickly introduces the user towards finer points like asset pipelining and is followed up on the next chapter by introducing different JVM based servers to run and deploy the web application. Lightweight Java servers and developer productivity tools are listed in the couple of following chapters, which I think do not add much value to the overall premise of the book. The next chapter then covers the design and principals of RESTful web services and demonstrates one created in Jersy which is then followed up by jQuery.

However, the Chapter 10 covers Angular and Sinatra (a mini-web framework in ruby) which is a let down as Java8 has provided native node.js runtime through project Rhino and it would have been interesting to see angular being used in the full MEAN stack (MongoDB, Express.js, Angular.js and Node.js) as express.js is the De-facto framework in the node.js land and angular and express share quite a lot in common. That said, beginners to Angular should use this chapter to get a feel of angular and do not worry much about the choice of server side framework used to provide the RESTful service to the client side application in question. This chapter covers Angular.js in sufficient detail and covers the actual theme of the book but at the end of the chapter, as a user I am left wanting for more - especially given the multitude of client side frameworks available as of today. I will definitely keep an eye open for improvements in this chapter in the future revisions of this book.

The final three chapters deal with the packaging and deployment and touches these areas briefly - it covers just the starting pointers and the users can themselves choose the tools to learn further as they need more.
Another plus I found with this book was a well balanced Appendix - on one hand, practical examples on using different lightweight databases were given and on the other hand, various facts and trivia regarding REST was detailed.

Overall, this book is a gem of knowledge to existing/new programmers who are starting looking into the exciting world of client side javascript based webapps that interact mainly with lightweight web services.
For a few sections where a simple Java based Restful service is demonstrated, sinatra running on jRuby is created which is fine, but can potentially confuse some java programmers who are not familiar with the ruby/jruby landscape. Instead, some offshoot library of Sinatra created in Java could've been used. This apart from the smaller chapter 10 and the fact that any other client side framework and tools like grunt/bower have no mention is my main grouse from the otherwise stellar book that deserves a read for those who are starting up on new age web apps.

Disclaimer: I have been provided a free copy of this book by OReilly under their Blogger review program.