Dear Stian and Alan, > We should probably make it so that if there's an example value, we > should rather fallback to using the example rather than the > RuntimeException when the user did not provide that input. > Alternatively we would need a second 'Default value' annotation on the > input port. I'll note a bug report about this issue.
I have been thinking about this solution (just thinking out loud here, I hope this feedback helps). Simply falling back to the example value would be very convenient if you wish to leave a certain input port optional. But if a user set value is required and the user somehow manages to forget it (I can imagine this could happen in more complicted workflows), there will be no error specifically stating 'user, you forgot to give that value'. For this reason I would go with implementing an 'default value' field. The workflow will fallback to this value, find that none was set and report a missing value error. > However, implementing > http://www.mygrid.org.uk/dev/issues/browse/T2-1239 would not require > any additional services to your workflow. It would simply be some > options you set on the first processor(s) after the input port. > Basically it is "On error on input X, instead use value Y". > > This was generally thought to be used for error coping when an > upstream service failed, but we found that most users did not > generally want to use a 'made up' value to hide a service error. I > believe such functionality would be most useful in cases such as you > suggest, where there is a beanshell script that knows how to deal with > input errors, where some input ports are not essential to the further > execution. Although I could solve my problem with a feature such as described in http://www.mygrid.org.uk/dev/issues/browse/T2-1239, I would prefer the above solution: an optional default value field. Cheers, Wil ------------------------------------------------------------------------------ _______________________________________________ taverna-users mailing list [email protected] [email protected] Web site: http://www.taverna.org.uk Mailing lists: http://www.taverna.org.uk/about/contact-us/
