Dealing with a bad symbolic reference in scala

Every time this hits me I have to think about it. The compiler barfs at you with something ambiguous like

[error] error: bad symbolic reference. the classpath might be incompatible with the version used when compiling Foo.class.

What this really is saying is that Foo.class references some import or class whose namespace isn’t on the classpath or has fields missing.… Read the rest

Unit testing DNS failovers

Something that’s come up a few times in my career is the difficulty of validating if and when your code can handle actual DNS changes. A lot of times testing that you have the right JVM settings and that your 3rd party clients can handle it involves mucking with hosts files, nameservers, or stuff like Route53 and waiting around.… Read the rest

Auto scaling akka routers

I’m working on a project where I need to multiplex many requests through a finite set of open sockets. For example, I have 200 messages, but I can only have at max 10 sockets open. To accomplish this I’ve wrapped the sockets in akka actors and am using an akka routing mechanism to “share” the 10 open sockets through a roundrobin queue.… Read the rest

Tiny types scala edition

Previously I wrote about generating value type wrappers on top of C# primitives for better handling of domain level knowledge. This time I decided to try it out in scala as I’m jumping into the JVM world.

With scala we don’t have the value type capability that c# has, but we can sort of get there with implicits and case classes.… Read the rest

Simple log context wrapper

I’m still toying around with the scala play! framework and I wanted to check out how I can make logging contextual information easy. In the past with .NET I’ve used and written libraries that wrap the current log provider and give you extra niceties with logging.… Read the rest