KPM: refactor BaseArtifact to provide a uniform artifact_info

[sbrossie]

We currently construct the artifact_info with a a lot of useful fields such as:

• dir_name
• bundle_dir
• file_path
• repository_path

However the definition for those entries is not consistent across artifacts:

• For ruby plugin:
  • dir_name = file_path = pluginDir/ruby
  • repository_path points to the tar.gz (e.g /org/kill-bill/billing/plugin/ruby/payment-test-plugin/1.8.7/payment-test-plugin-1.8.7.tar.gz)
  • bundle_dir = pluginDir/ruby/plugin_name/plugin_version (BUT ONLY AFTER it has been successfully installed).
• For java plugin:
  • dir_name = pluginDir/java/plugin_name/plugin_version
  • repository_path points to the jar (e.g /org/kill-bill/billing/plugin/java/analytics-plugin/0.7.1/analytics-plugin-0.7.1.jar)
  • file_name = jar
  • file_path = dir_name/file_name
  • bundle_dir = dir_name (BUT ONLY AFTER it has been successfully installed).

Did not investigate the case for pure OSGI default bundles, kaui or killbill war, but that should also be consistent so we can extract clear definition from those fields.

[sbrossie]

We should also address other maintainability issues in the file:

• For instance update_destination_path extract plugin_dir, version_dir = File.split(destination_path) but that is only true for java plugins
• In populate_fs_info what is path_looks_like_a_directory and what do we try to do?

[sbrossie]

Suggestion for improvement:

Since BaseArtifact is the base class, we could hide magic detail for how those fields are computed in the KillbillPluginArtifact, KillbillServerArtifact, ...

Might even be useful to distinguish between KillbillJavaPluginArtifact and KillbillRubyPluginArtifact since they are so different and then all the logic with 'tgz',... could be hidden.