Friday, November 27, 2009
Future of mobile data
Good article on looming bandwidth issues in mobile data (via @timbray).
BT currently do the share-your-home-DSL thing in the UK currently. I'd like that ability but my provider doesn't do it, and going for BT DSL is not a risk I'm willing to take right now. Which is a shame cos the streaming TV is another good product -- why should I need to buy the line from them too? The customer service reputation is so bad, I just can't contemplate it.
Revenue sharing would require the mother of entitlements apps, plus trusted end-points / bandwidth monitoring, which is fine for most people, but how do you avoid someone claiming all their traffic was 3rd party? Using IPv6 to avoid the NAT issues? A side effect is to explode the insanities in the Digital Economy Bill currently running around in the UK (media firms getting connections terminated without going to court, regardless of number of people using them).
Thursday, November 05, 2009
GWT 2.0 and classpath hell
I had a little visit back to classpath hell yesterday. I'm building an app using GWT for the front end. For mad Mac OS / Java / 3rd party native libs reasons, I wanted to move to OOPHM (29West only do 64bit libs on a Mac..) so I installed GWT 2.0 ms2. It was all looking good, against Firefox (other than needing it's own launch config rather than the eclipse plugin's launch), and ran at a similar speed in dev mode.
[ slight issue is that I then changed project for a few days, forgetting the exact last change.. ]
I then change a section of code to handle a bit of the data model I was getting wrong previously. Time to rerun the unit tests. Bang. Except, the code that dies is inside the protocol buffers library (which I'm using to talk to a back end server). Just to add layers to the confusion I'm calling protobuf methods via reflection (since all the type stuff in protobuf is accessed via non-polymorphic static methods on each class -- eek). Giving me lots of nested exceptions with InvocationTargetException / NoSuchMethodError, implying I though, my reflection code was broken.
Now, various projects are on either protobuf 2.0.2 or 2.2.0. The generated code for one, is not compatible with the libs of the other. I then spend ages looking at classpaths and trying to work out what's change. I write a test class, without any reflection to find I can't even reference a generated class without the exploding. :/
The wierd thing was, OOPHM still worked, calling the same code, it's was just my unit tests that were dying. Eventually I find the culprit, gwt-dev.jar, contains approx half the known Java universe including protobuf 2.2.0. Gaa!! It seems the webapp classloader magic for OOPHM/Jetty was hiding the problem. Luckily, a judicious, if hacky, move of GWT libs to the end of the classpath fixed the problem temporarily.
So I'll end with a plea to both Google and any other software projects -- please do build on top of other stable libraries but either:
PS GWT rocks, thank you Google.
[ slight issue is that I then changed project for a few days, forgetting the exact last change.. ]
I then change a section of code to handle a bit of the data model I was getting wrong previously. Time to rerun the unit tests. Bang. Except, the code that dies is inside the protocol buffers library (which I'm using to talk to a back end server). Just to add layers to the confusion I'm calling protobuf methods via reflection (since all the type stuff in protobuf is accessed via non-polymorphic static methods on each class -- eek). Giving me lots of nested exceptions with InvocationTargetException / NoSuchMethodError, implying I though, my reflection code was broken.
Now, various projects are on either protobuf 2.0.2 or 2.2.0. The generated code for one, is not compatible with the libs of the other. I then spend ages looking at classpaths and trying to work out what's change. I write a test class, without any reflection to find I can't even reference a generated class without the
The wierd thing was, OOPHM still worked, calling the same code, it's was just my unit tests that were dying. Eventually I find the culprit, gwt-dev.jar, contains approx half the known Java universe including protobuf 2.2.0. Gaa!! It seems the webapp classloader magic for OOPHM/Jetty was hiding the problem. Luckily, a judicious, if hacky, move of GWT libs to the end of the classpath fixed the problem temporarily.
So I'll end with a plea to both Google and any other software projects -- please do build on top of other stable libraries but either:
Make it explicit -- leave the versioned jars outside the project jars, fore-warned is fore-armed Protect your clients -- Use a classloader to hide your dependencies, or use a jar-creator (jarjar / onejar etc) to change the namespaces.
PS GWT rocks, thank you Google.
