Command.java

/*
 * This class holds information about a command that was issued by the user.
 * A command currently consists of two strings: a command word and a second
 * word (for example, if the command was "take map", then the two strings
 * obviously are "take" and "map").
 * 
 * The way this is used is: Commands are already checked for being valid
 * command words. If the user entered an invalid command (a word that is not
 * known) then the command word is <null>.
 *
 * If the command had only one word, then the second word is <null>.
 *
 * The second word is not checked at the moment. It can be anything. If this
 * game is extended to deal with items, then the second part of the command
 * should probably be changed to be an item rather than a String.
 */

class Command
{
    private String commandWord;
    private String secondWord;

    /**
     * Create a command object. First and second word must be supplied, but
     * either one (or both) can be null. The command word should be null to
     * indicate that this was a command that is not recognised by this game.
     */
    public Command(String firstWord, String secondWord)
    {
        commandWord = firstWord;
        this.secondWord = secondWord;
    }

    /**
     * Return the command word (the first word) of this command. If the
     * command was not understood, the result is null.
     */
    public String getCommandWord()
    {
        return commandWord;
    }

    /**
     * Return the second word of this command. Returns null if there was no
     * second word.
     */
    public String getSecondWord()
    {
        return secondWord;
    }

    /**
     * Return true if this command was not understood.
     */
    public boolean isUnknown()
    {
        return (commandWord == null);
    }

    /**
     * Return true if the command has a second word.
     */
    public boolean hasSecondWord()
    {
        return (secondWord != null);
    }
}