2015 in review

The WordPress.com stats helper monkeys prepared a 2015 annual report for this blog.

Here’s an excerpt:

The Louvre Museum has 8.5 million visitors per year. This blog was viewed about 200,000 times in 2015. If it were an exhibit at the Louvre Museum, it would take about 9 days for that many people to see it.

Click here to see the complete report.

NDC: Async and Streaming JavaScript, We’re All Doing it Wrong! (Promises, Streams, Rx)

By Matthew Podwysocki

Events

Lot of work (setup, remove listeners …), not composable.

Promises

No way to abort promise in progress. (Me: has to remember to check for errors: then(onOk, onError).)

No try-catch-finally; only try-catch.

Streams

Node: Stream 1 were terrible (pause/resume unusable, data sent before ready, …).

Why do companies fail at adopting Functional Programming?

According to the NDC Oslo talk Lean and Functional Programming by Bryan Hunter, these are the reasons why companies fail to adopt FP:

• They say “our developers aren’t smart enough” (to use F#, Erlang) [they should invest in their education!]
• Culture of hiding problems => little incentive to adopt a paradigm that solves/prevents them if they’re invisible
• Overburden => not time
• Implementing changes (FP) without first proving them (PDCA) – blindly rewriting something in F#/… can fail; it’s better to have a value-proposition hypothesis and prove it with a limited experiment first
• The prioritise short-term (e.g. fire-fighting) over long-term (removing the root causes of problems)

Tip for driving FP adoption: Find a pragmatist in pain – e.g. a business person experiencing problems that FP could have prevented.

Fix Shell Script Run via SSH Hanging (Jenkins)

There is an important difference between running a script manually (ssh machine; machine$ ./script.sh) and running it via ssh (ssh machine < script.sh): in the letter case the connection will not close when the script finishes but will stay open until stdout/stderr are closed or a timeout occurs. In Jenkins it will therefore seem as if the script hangs.

So if your shell scripts starts any background job, make sure to redirect all its output to somewhere:

nohup some-background-task &> /dev/null   # No space between & and > !

This has bitten me when trying to deploy an application from the Jenkins CI using SSH and a shell script.

References: http://www.snailbook.com/faq/background-jobs.auto.html

The blog’s year 2014 in review

The WordPress.com stats helper monkeys prepared a 2014 annual report for this blog.

Here’s an excerpt:

The Louvre Museum has 8.5 million visitors per year. This blog was viewed about 170,000 times in 2014. If it were an exhibit at the Louvre Museum, it would take about 7 days for that many people to see it.

Click here to see the complete report.

Connect Tunnelblick to VPN automatically after wake up

Need: Make sure that VPN is always running except when at work.

Partial solution: Make sure VPN is always running with “connect when computer starts” and using an AppleScript to connect after waking up from sleep. Disconnect manually when at work.

Future: Check the current location (wifi name? IP?) and do not connect when at work.

Petitioning EU to act against Russian aggression in Ukraine

As a citizen of a country that has been invaded by Hilter in 1938 under the pretext of protecting local Germans and again invaded by Russia in 1968, I cannot watch another such invasion and annexation taking place in Europe while EU does little of any consequences.

Please consider signing the petition to EU to act against Russian aggression with all the political and economical power it has, even if – oh the horror – will cost our wallets too.

Click here to join:
European Union, Catherine Ashton, Herman van Rompuy: Act on Ukraine. Immediately!

Protected: JavaServer Faces Are Evil (draft)

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2013 in review

The WordPress.com stats helper monkeys prepared a 2013 annual report for this blog.

Here’s an excerpt:

The Louvre Museum has 8.5 million visitors per year. This blog was viewed about 140,000 times in 2013. If it were an exhibit at the Louvre Museum, it would take about 6 days for that many people to see it.

Click here to see the complete report.

How I Learned to Avoid Magical Dependency Injection And Love Plain Java

A short story about the complexity of magical frameworks and dependency injection with a happy ending, featuring Resteasy, CDI, and JBoss.

Once upon time, I have created a JAX-RS webservice that needed to supply data to a user’s session. I wanted to be fancy and thus created a @Singleton class for the exchange of information between the two (since only a user request serving code can legally access her session, a global data exchange is needed). However sharing the singleton between the REST service and JSF handler wasn’t so easy:

• Originally, the singleton was generic: OneTimeMailbox<T> – but this is not supported by CDI so I had to create a derived class (annotated with @Named @Singleton)
• While everything worked in my Arquillian test, at runtime I got NullPointerException because the @Inject-ed mailbox was null in the service, for reasons unclear. According to the internets, CDI and JAX-RS do not blend well unless you use ugly tricks such as annotating your service with @RequestScoped (didn’t help me) or use JBoss’ resteasy-cdi module.

Finally I got fed up by all the complexity standing in my way and reverted to plain old Java singleton (OneTimeMailbox.getInstance()) while making testing possible with multiple instances by having a setter an alternative constructor taking the mailbox on each class using it (the service and JSF bean) (using a constructor might be even better).

Result? Actually better testability and simpler code.

Bjørn Borud and Johannes Brodwall were right – plain old Java is better than magical frameworks and magical DI is evil. (Though they would diapprove of JBoss and likely prefered if I used a plain servlet instead of JAX-RS for my very simple case.)

Update: As pointed out by Daniel Kolman now and others previously, dependency injection itself isn’t bad (though some would argue), it is only magic DI that is a problem. You can well do DI yourself using plain old Java – see Bakksjø: The inverse of IoC is Control, Perry: Do-It-Yourself Dependency Injection (pdf; quote: “[..] shows how dependency injection can be accomplished without any framework. The same benefits provided by frameworks can be realized using “do-it-yourself” (DIY) handcrafted code.“; recommended by Google’s test master Miško Hevery who is a fan of DI because it helps with testability).