Hi Nikhil,
One hit direct navigation is a standard functionality implemented in standard components. You can refer any standard search component - > search view -> search event for that.
eg. the component BP_HEAD_SEARCH - BP_HEAD_SEARCH/MainSearch.
Check the event EH_ONSEARCH, where you can find the method
cl_crm_uiu_one_hit_direct_nav=>navigate_if_result_is_unique( ).
Thanks & Best Regards,
Leon