Example 2-2 is a standalone program named RectTest that puts the Rect class of Example 2-1 through its paces. Note the use of the new keyword and the Rect( ) constructor to create new Rect objects. The program uses the . operator to invoke methods of the Rect objects and to access their fields. The test program also relies implicitly on the toString( ) method of Rect when it uses the string concatenation operator (+) to create strings to be displayed to the user. Example 2-2. RectTest.javapackage je3.classes; /** This class demonstrates how you might use the Rect class */ public class RectTest { public static void main(String[ ] args) { Rect r1 = new Rect(1, 1, 4, 4); // Create Rect objects Rect r2 = new Rect(2, 3, 5, 6); Rect u = r1.union(r2); // Invoke Rect methods Rect i = r2.intersection(r1); if (u.isInside(r2.x1, r2.y1)) // Use Rect fields and invoke a method System.out.println("(" + r2.x1 + "," + r2.y1 + ") is inside the union"); // These lines implicitly call the Rect.toString( ) method System.out.println(r1 + " union " + r2 + " = " + u); System.out.println(r1 + " intersect " + r2 + " = " + i); } } |