// In Command sub-classes we basically interact with entities of the core (call methods) // In Command sub-classes we need to implement: // // 1. The constructor, that typically receives one or more objects of the core. // We have to call the constructor of the super-class (usually with a title and the entity of the core) // 2. The method execute(), that calls the methods of the core entities // // User interaction (input and output data) is done using the classes Form and Display as shown import pt.utl.ist.po.ui.*; // po-uilib classes import java.util.List; public class ListNumbers extends Command<CoreEntity> { //Constructor public ListNumbers(CoreEntity ent) { super("List Numbers", ent); } public void execute() { // executed when this option is selected Display d = new Display(title()); List<Integer> list = entity().getNumbers(); for (Integer number : list) d.addNewLine(number.toString()); d.display(); } }