how to call apex in action framework?? Please Help me asap

https://docs.skuid.com/v10.0.2/en/data/salesforce/index.html?&_ga=2.267804998.930489331.1505245114-479373592.1484921929#data-source-actions

https://docs.skuid.com/latest/en/skuid/action-framework/action-framework.html?&_ga=2.20876784.930489331.1505245114-479373592.1484921929#data-source-specific-actions

Can we Display all contacts of the account in frontend with help of Apex class??