[buckminster-dev] ResourceMap and properties

[Thomas Hallgren <thomas@xxxxxxx>]

I'm using Buckminster to materialize an assembly that doesn't use 
Eclipse at all. It uses its own set if pre-compiled binaries for 
compilation. Different platforms have a different set of buildtools and 
the materialization must be able to cope with that (the buildtools are 
components that take part of the materialization).

At first I suggested use of federated resource maps, i.e. depending on 
what platform you're on, you front the original rmap with one that finds 
platform specific components. People in the project objected to this 
because they find the rmap too complex. They use emacs or the like to 
setup the build and they want to use Buckminster as a headless tool 
only. Editing XML documents didn't appeal to them. Ideally, they'd like 
to have a property file that they can use to control the process.

The way the rmap is constructed today it can contain site specific 
properties. The url's and other parameters for the providers are all 
subject to property expansion. The sites are defined in the rmap itself. 
We've had this up for debate before and now I think it's time to make 
some changes. I propose two things:

1. Drop the site concept from the rmaps and more all property settings 
to the top of the rmap. By doing so, the rmap can specify a set of 
default properties.
2. Add a URL to the cquery that appoints a properties file (simple Java 
.properties format). Let the properties in this file override the ones 
defined in the rmap.
3. Remove the current 'site name' setting from the Buckminster 
preferences and replace it with a URL that also appoints a property 
file. The properties in this file will also override the rmap properties 
but they too will be overridden by the properties appointed by the cquery.

We will then get four levels of properties, listed in descending order 
of priority:

- System properties (as defined by the JVM and by -Dxxx=yyy parameters 
at startup)
- Component Query specific properites (defined by a URL in the cquery)
- Site specific properties (defined by the URL in the Buckminster 
preferences)
- Resource Map specific properties (defined in the rmap)

Ideas? Suggestions?

Regards,
Thomas Hallgren