Fill in the blanks with lowercase letters $!!!!!$

Answer

In this question you are presented with $4$ blank fields that you should fill in according to their context. Read the surrounding text first, and then type your answer.

In command pattern, the

is send to the invoker and invoker pass it to the encapsulated command object. Command object passes the request to the appropriate method of receiver to perform the specific action. The

program create the receiver object and then attach it to the Command. Then it creates the

object and attach the command object to perform an action. Now when client program executes the action, it$$s processed based on the command and

object.