All of these operations will produce their own unique errors in the absence of
  a coordinated offline strategy. In addition, efforts to unite these failing
  behaviors behind a consistent user interface is much, much more difficult if
  the system can't tell whether it has access to the network required by these
  operations.

  Offline mode really means anticipating a lack of network connectivity, and as

        // snapshot timestamp, or some other timestamp later encoded into the metadata.
        // TODO this needs to be repeated here so the merging doesn't interfere with the written metadata
        //  - we'd be much better having a pristine input, and an ongoing metadata for merging instead

        Map<ArtifactRepository, Metadata> previousMetadata = new HashMap<>();
        ArtifactRepository selected = null;

h3. Plugins need a specific metadata model

Each application will have its own model for plugins. Much of this model will be common across applications but there will always be issues specific to a particular applications’s plugins. Some of the issues that need to be taken into consideration:

* Plugin dependencies