citrus-framework - Validate the data from a Json File

Question

I got this error message while trying to execute the get method.

Validation failed: Values not equal for element '$..userName', expected 'admin' but was '["admin",null,"HiCitrus","Unisys1","dscsc"]'

This is the script I have used:

 http().client(todoClient)
       .send()
       .get("/rest/api/user/allusers")
       .contentType("application/json");                 

 http().client(todoClient)
       .receive()  
       .response(HttpStatus.OK)     
       .messageType(MessageType.JSON)
   //  .validate(path, controlValue);
       .validate("$..userName","admin");"

There are multiple parameters available for the username - is there a way to validate if I find the username "Admin"? Tried with the code below, but it's throwing an error.

.validate("$..userName",contains("admin"));