All, Whenever we've to write new APIs, we end up putting a lot of validations such as Strings.isNullOrEmpty or checks on API args such as on id we do this a lot getId() != null && getId() > 0 and on failing throw server api exception (as cloudstack entity ids are always > 0, such as ids of vms, volumes etc).
While working on recent dynamic-roles PR, I ended up writing several such validations for all the new APIs and based on suggestions from John I could rid of all such checks by introducing a new @Parameter annotation field call validators() which is a list of validators we want to run for an API arg. This does not break any existing API which might have inconsistent assumptions (such as few accept id to be -1), and on local env all existing unit tests and smoke tests have passed. Please find an implementation in the dynamic-roles PR where all the new dynamic roles APIs use these annotations: https://github.com/apache/cloudstack/pull/1489 Ticket: https://issues.apache.org/jira/browse/CLOUDSTACK-9361 As soon as the PR is accepted and merged, I'll update the wiki page and we can get this pattern adopted over time: https://cwiki.apache.org/confluence/display/CLOUDSTACK/Annotations+use+in+the+API Regards, Rohit Yadav Regards, Rohit Yadav rohit.ya...@shapeblue.com www.shapeblue.com 53 Chandos Place, Covent Garden, London WC2N 4HSUK @shapeblue
