Using XStream on Google App Engine

When building the new "Enrich contacts" feature I've been using GSon for parsing JSON responses.
This was super-easy and did work more or less instantly.
Unfortunately the LinkedIn API is using XML and strange enough it became quite complicated to parse XML on GAE.
I tried to find an approach similar to GSon for XML but due to security restrictions on App Engine I struggled to use XStream in the first place.
After finding a patched jar that allows to use XStram on GAE I was still surprised how complicated it was to map XML to fields. As XML typically uses dashes in tag names I thought it would map to camel-case syntax automatically, but XStream wanted me to define an alias for each mapping.
After getting an ever growing list of mappings I decided to create a mapper to do this once and for all.
As I assume that a lot of people face exactly the same problem, I'd like to share the code with you:

private static class CamelCaseMapper extends MapperWrapper {
	public CamelCaseMapper(Mapper wrapped) {
		super(wrapped);
	}

	@Override
	public String serializedMember(Class type, String memberName) {
		StringBuilder dashed = new StringBuilder();
		for (int i = 0; i < memberName.length(); i++) {
			if (Character.isUpperCase(memberName.charAt(i))) {
				dashed.append('-').
append(Character.toLowerCase(memberName.charAt(i)));
			} else {
				dashed.append(memberName.charAt(i));
			}
		}
		return super.serializedMember(type, dashed.toString());
	}

	@Override
	public String realMember(Class type, String serialized) {
		int index = -1;
		while ((index = serialized.indexOf("-")) > -1) {
			serialized = serialized.substring(0, index) +
 String.valueOf(serialized.charAt(index + 1)).toUpperCase() +
 serialized.substring(index + 2);
		}
		return super.realMember(type, serialized);
	}
}

To convince XStream to use this custom mapper, create your XStream instance like this:

XStream xstream = new XStream(new DomDriver()) {
	protected MapperWrapper wrapMapper(MapperWrapper next) {
		return new CamelCaseMapper(next);
	}
};

New App Engine pricing model

A while ago Google announced a new pricing for Google App Engine.
As the pricing is totally different the preview for the new billing indicated a 15x increase for Shared Groups. This would have forced us to shut down the service completely - or to increase our prices for the personal edition according to the new pricing.
After some investigation we managed to optimize the app in a way that the usage dropped significantly and we are currently expecting a price increase by ~300%.
Still quite a lot - but it looks much better than in the first place ;-)
We are constantly working on reducing the resources consumed and will come up with recommendations for all enterprise users before the new pricing will take effect.

Welcome to our new dev blog

Everything that is not worth an official announcement will go here.

Stay tuned!