package UserInterface; class OutputMessage{ //unfinished definition, you could extends this class to make suitable functions private String easyMsg = ""; OutputMessage(){} public void setEasyMsg(String easyMsg) { this.easyMsg = easyMsg; } //get the final output message for UI, could be reload in the subclass public String getOutputMessage(){ return easyMsg; } } public interface UserInterface { public void getUserInput(String msg); public void ShowProgramOutput(OutputMessage outMsg); }