Re: [Geotools-devel] HashMap Considered Harmful

[Ben Caradoc-D. <Ben...@cs...>]

On 15/06/10 15:50, Andrea Aime wrote:
> Developer depending on hashmap order ->  chaos
> It's not the fault of poor hashmap that developers use it in a number
> of places where it's unnecessary if not even harmful.

But the poor developers cannot know if they are getting a HashMap if 
they are a module consumer and use, for example:

Map<String, String> getNamespaceSchemaLocationMap();

Is iteration over these namespaces stable across platforms? If we add 
one namespace is their order jumbled?

The module implementor who allows an instance of HashMap to be exposed 
has exposed the iteration order of the HashMap to an unsuspecting module 
user. I have nothing against HashMaps that are kept well hidden, but 
HashMaps allowed to leak out of confinement have an unerring ability to 
make program behaviour vary across platforms.

Kind regards,

-- 
Ben Caradoc-Davies <Ben...@cs...>
Software Engineering Team Leader
CSIRO Earth Science and Resource Engineering
Australian Resources Research Centre