OBJECT-ORIENTED THINKING - Introduction to Java Programming: Comprehensive Version - page 405

A method getArea() that returns the area of the rectangle.

■

A method getPerimeter() that returns the perimeter of the rectangle.

■

A method contains(double x, double y) that returns true if the
specified point ( x , y ) is inside this rectangle (see Figure 10.24a).

■

A method contains(MyRectangle2D r) that returns true if the speci-
fied rectangle is inside this rectangle (see Figure 10.24b).

■

A method overlaps(MyRectangle2D r) that returns true if the speci-
fied rectangle overlaps with this rectangle (see Figure 10.24c).

■

p

(a) (b) (c) (d)

F IGURE 10.24

A point is inside the rectangle. (b) A rectangle is inside another rectangle.
(c) A rectangle overlaps another rectangle. (d) Points are enclosed inside a rectangle.

Draw the UML diagram for the class and then implement the class. Write a test
program that creates a MyRectangle2D object r1 ( new MyRectangle2D(2,
2, 5.5, 4.9) ), displays its area and perimeter, and displays the result of
r1.contains(3, 3) , r1.contains(new MyRectangle2D(4, 5, 10.5,
3.2)) , and r1.overlaps(new MyRectangle2D(3, 5, 2.3, 5.4)) .

*10.14

( The MyDate class ) Design a class named MyDate . The class contains:

The data fields year , month , and day that represent a date. month is
0-based, i.e., 0 is for January.

■

A no-arg constructor that creates a MyDate object for the current date.

■

A constructor that constructs a MyDate object with a specified elapsed time
since midnight, January 1, 1970, in milliseconds.

■

A constructor that constructs a MyDate object with the specified year,
month, and day.

■

Three getter methods for the data fields year , month , and day , respectively.

■

■ A method named setDate(long elapsedTime) that sets a new date for
the object using the elapsed time.
Draw the UML diagram for the class and then implement the class. Write a
test program that creates two MyDate objects (using new MyDate() and new
MyDate(34355555133101L) ) and displays their year, month, and day.
( Hint : The first two constructors will extract the year, month, and day from
the elapsed time. For example, if the elapsed time is 561555550000 milli-
seconds, the year is 1987 , the month is 9 , and the day is 18 . You may use the
GregorianCalendar class discussed in Programming Exercise 9.5 to sim-
plify coding.)

*10.15

( Geometry: the bounding rectangle ) A bounding rectangle is the minimum rec-
tangle that encloses a set of points in a two-dimensional plane, as shown in
Figure 10.24d. Write a method that returns a bounding rectangle for a set of
points in a two-dimensional plane, as follows:

public static MyRectangle2D getRectangle( double [][] points)