Currently, TemplateDialog has responsibility for checking that template parameters have valid values. So far this only tests that required parameters have values, if not it shows a warning, and lets the editor confirm to continue.

This is implemented with low-level access to the booklet layout, so decide which of these approaches to take:

• Expose a "get all parameters for all templates" interface.
  • Pros: warning modals are already a responsibility of the Dialog layer.
  • Cons: this is low-level; this breaks proposed per-template encapsulation; parameter-level validation is unlike other responsibilities of TemplateDialog.
• or, extract to a new class for validating and warning.
  • Pros: very clean; provides a target for any additional validation.
  • Cons: we aren't planning to add more validation.
• or, push responsibility into the high-level booklet interface and expose as validateAllParameterValues().
  • Pros: exposes a prety nice interface.
  • Cons: validation is a new type of responsibility for this class. Workflow should probably be implemented by breaking the validation into a "generate warnings" step handled by the booklet helper, and a "present warnings" step handled by the Dialog. The validation method's return value would be complex, e.g. a list of Status object.