/** * This class is part of the "World of Zuul" application.  * "World of Zuul" is a very simple, text based adventure game.   *  * This class holds an enumeration of all command words known to the game. * It is used to recognise commands as they are typed in. * * @author  Michael Kolling and David J. Barnes * @version 2006.03.30 */public class CommandWords{    // a constant array that holds all valid command words    private static final String[] validCommands = {        "go", "quit", "help"    };    /**     * Constructor - initialise the command words.     */    public CommandWords()    {        // nothing to do at the moment...    }    /**     * Check whether a given String is a valid command word.      * @return true if a given string is a valid command,     * false if it isn't.     */    public boolean isCommand(String aString)    {        for(int i = 0; i < validCommands.length; i++) {            if(validCommands[i].equals(aString))                return true;        }        // if we get here, the string was not found in the commands        return false;    }}