Predicates: snowing and weekend

Consequences: go to work, read a book, shovel the driveway, ski:
 

snowing	weekend	activity
false	false	go to work
false	true	read a book
true	false	shovel driveway
true	true	go skiing

*/

import javax.swing.JOptionPane;
import psJava.KeyIn;

class ActivityExpert  {
    public boolean snowing;
    public boolean weekend;

    // flat rules
    public String flatRules(){
        if (!snowing && !weekend) return "go to work";
        if (!snowing && weekend) return "read a book";
        if ( snowing && !weekend) return "shovel driveway";
        if ( snowing && weekend) return "go skiing";
        // Note the need for a "drop through" return, or the compiler complains.
        return "Error! no rule invoked";
    }
 

    // cascadingElse
    public String cascadingElse() {
        if (!snowing && !weekend)
            return "go to work";
        else if (!snowing && weekend)
            return "read a book";
        else if ( snowing && !weekend)
            return "shovel driveway";
        else if ( snowing && weekend)
            return "go skiing";
        else return "Error! no rule invoked";
    }

    // decision tree
    public String decisionTree() {
        if (snowing) {
            if (weekend)
                return "go skiing";
            else
                return "shovel the driveway";
        } else {
            if (weekend)
                return "read a book";
            else
                return "go to work";
        }
    }

    public void testRules() {

        JOptionPane.showMessageDialog(null, "Testing flat list");
        snowing = false;
        weekend = false;
        JOptionPane.showMessageDialog(null, "Not snowing, not weekend " + flatRules());

        snowing = false;
        weekend = true;
        JOptionPane.showMessageDialog(null, "Not snowing, weekend " + flatRules());

        snowing = true;
        weekend = false;
        JOptionPane.showMessageDialog(null, "Snowing, not weekend " + flatRules());

        snowing = true;
        weekend = true;
        JOptionPane.showMessageDialog(null, "Snowing, weekend " + flatRules());

        JOptionPane.showMessageDialog(null, "");
        JOptionPane.showMessageDialog(null, "Testing cascade");
        snowing = false;
        weekend = false;
        JOptionPane.showMessageDialog(null, "Not snowing, not weekend " + cascadingElse());

        snowing = false;
        weekend = true;
        JOptionPane.showMessageDialog(null, "Not snowing, weekend " + cascadingElse());

        snowing = true;
        weekend = false;
        JOptionPane.showMessageDialog(null, "Snowing, not weekend " + cascadingElse());

        snowing = true;
        weekend = true;
        JOptionPane.showMessageDialog(null, "Snowing, weekend " + cascadingElse());

        JOptionPane.showMessageDialog(null, "");
        JOptionPane.showMessageDialog(null, "Testing Decision Tree");
        snowing = false;
        weekend = false;
        JOptionPane.showMessageDialog(null, "Not snowing, not weekend " + decisionTree());

        snowing = false;
        weekend = true;
        JOptionPane.showMessageDialog(null, "Not snowing, weekend " + decisionTree());

        snowing = true;
        weekend = false;
        JOptionPane.showMessageDialog(null, "Snowing, not weekend " + decisionTree());

        snowing = true;
        weekend = true;
        JOptionPane.showMessageDialog(null, "Snowing, weekend " + decisionTree());

        JOptionPane.showMessageDialog(null, "");
    }

    public void userInput() {
        snowing = KeyIn.readBoolean("Snowing?");
        weekend = KeyIn.readBoolean("Weekend?","yes", "no");

        JOptionPane.showMessageDialog(null, decisionTree());

    }

} // ActivityExpert