Wednesday, April 11, 2012

Philly Emerging Tech Conference: Day Two

This post describes what I've learned during the second half of the Philly Emerging Technologies for the Enterprise Conference. See my previous blog post for a description of the first day. It was a great conference and I had a blast!

Keynote Address - Emerging Programming Languages

by Alex Payne

Alex started his talk by repeating the most common complaint people have about new languages--"why do we need another programming language?" His answer? Because evolution is a process that's constantly in motion--there's no way of knowing where the "jumping off point" is. As he gave this answer, a picture showing the evolution of the human skull was displayed behind him, implying that we are the result of a similar, albeit slower, kind of change (biological evolution).

When learning about new languages, which Alex does as a hobby, Alex's end goal isn't necessary to use the language, but to learn about the language's unique features and to try to incorporate those features into his work. One language he gave as an example had a certain elegant way of working with WSDLs which compelled him to implement a similar feature into one of his projects.

Alex described around two dozen very obscure programming languages, only 2 of which I've ever heard of (Go and CoffeeScript). He divided the languages up into categories, such as "Web Development", "Dynamic Programming", and "Querying Data".

Behind the scenes of Spring Batch

by Josh Long

Spring Batch is a Spring module that makes creating batch processes more standardized and less error prone. You basically define your job in an XML file. Then, using a combination of custom Java code and classes from the Spring Batch API, you write the logic of your batch job. It streams the batch data by reading the individual entry elements from the input data one by one and then writing out the processed data in chunks (e.g. 10 entries at a time). Because of this, you don't have to worry about getting OutOfMemory errors when processing large amounts of data.

I also thought it was cool that you can schedule your job to run on a regular basis by giving it a cron expression. In addition, you can have it generate a small web app that allows you to view the status of your jobs from the browser.

One thing that took me a little by surprise is that Spring Batch requires a connection to a database. It uses this database basically for logging purposes, like keeping track of the times the job ran and recording the errors that occurred (if any) while the job was running.

Spring Batch looks like a very clean and robust way of working with batch jobs. I definitely want to look more into it.

Dependency Injection Without the Gymnastics - Functional Programming Applied

by Runar Bjarnason and Tony Morris

This presentation was pretty unique in that the speaker, Tony, gave his talk via Skype from Australia! Runar was there in person and acted as the technician and the intermediary between the audience and Tony. It was about how to do dependency injection in Scala without having to resort to confusing XML files like with Spring.

The CoffeeScript Edge

by Trevor Burnham

Trevor explained some of the benefits that CoffeeScript brings to the table in this presentation. For example, following one of Douglas Crockford's words of wisdom, the Javascript code that CoffeeScript generates will never use the "==" operator. When comparing two variables in CoffeeScript, the syntax "x is y" is used, which translates to "x === y" in Javascript.

CoffeeScript also supports string interpolation, which allows you to concatenate strings using a cleaner syntax. For example:

dog = 'Spot'
x = "See #{dog}. See #{dog} run."

Another nice perk in CoffeeScript is that you don't have to separate array elements with commas if they are on separate lines. For example:

arr = [

You can also use the @ operator as shorthand for this.

Trevor also made an interesting point about the increasing popularity of Javascript. Due to the increased usage of Javascript on the web, all the major browser makers (Microsoft, Google, Mozilla, Apple, and Opera) have been pouring money into making the language faster on their browsers. It's quite possible that no language in the history of computing has ever received this much financial backing.

JavaScript Testing: Completing the BDD Circle in Web Development

by Trevor Lalish-Menagh

This talk focused on how to write unit tests for Javascript code. Trevor did some live coding using some pretty impressive vim-foo, showing how to unit test Javascript code using the Jasmine framework. An important concept that he discussed was "spying" on functions. I'm not sure if this is unique to Jasmine, but it allows you determine whether a particular function was called or not, something that's very helpful in unit testing. Trevor also showed that it's possible to integrate your Javascript unit tests into a Maven build script.

Effective Scala

by Joshua Suereth

Joshua's talk focused on providing fairly advanced tips for writing good Scala code. He stressed the importance of using the Scala REPL (an interactive interpreter) during development. The REPL should be used on a regular basis to experiment with unfamiliar libraries and test out snippets of code. He also stressed the importance of staying immutable. If your objects are immutable, then it means (1) they are thread-safe and (2) they are hash-safe. He says that you should write your interfaces in Java because the bytecode of Scala interfaces doesn't convert well back to Java.

Joshua talked in depth about what's called "implicit scope". This is a special scope that basically lets you insert whatever variables you want into it. If used properly, it can be very powerful. One example Joshua gave was using implicit scope to define a collection of "Encoder" classes which convert various objects to byte arrays. It's designed that so any object can be passed into an "Encoder.encode()" method. Then, using implicit scope, the method delegates the object to the appropriate "Encoder" implementation for further processing.

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