Inheritance - Data Structures and Problem Solving Using Java - page 162

1 import java.util.Comparator;
2
3 class CompareTestInner1
4 {
5 private static class OrderRectByWidth implements Comparator<SimpleRectangle>
6 {
7 public int compare( SimpleRectangle r1, SimpleRectangle r2 )
8 { return r1.getWidth( ) - r2.getWidth( ); }
9 }
10
11 public static void main( String [ ] args )
12 {
13 SimpleRectangle [ ] rects = new SimpleRectangle[ 4 ];
14 rects[ 0 ] = new SimpleRectangle( 1, 10 );
15 rects[ 1 ] = new SimpleRectangle( 20, 1 );
16 rects[ 2 ] = new SimpleRectangle( 4, 6 );
17 rects[ 3 ] = new SimpleRectangle( 5, 5 );
18
19 System.out.println( "MAX WIDTH: " +
20 Utils.findMax( rects, new OrderRectByWidth( ) ) );
21 }
22 }
figure 4.42
Using a nested class to hide the OrderRectByWidth class declaration
1 class CompareTestInner2
2 {
3 public static void main( String [ ] args )
4 {
5 SimpleRectangle [ ] rects = new SimpleRectangle[ 4 ];
6 rects[ 0 ] = new SimpleRectangle( 1, 10 );
7 rects[ 1 ] = new SimpleRectangle( 20, 1 );
8 rects[ 2 ] = new SimpleRectangle( 4, 6 );
9 rects[ 3 ] = new SimpleRectangle( 5, 5 );
10
11 class OrderRectByWidth implements Comparator<SimpleRectangle>
12 {
13 public int compare( SimpleRectangle r1, SimpleRectangle r2 )
14 { return r1.getWidth( ) - r2.getWidth( ); }
15 }
16
17 System.out.println( "MAX WIDTH: " +
18 Utils.findMax( rects, new OrderRectByWidth( ) ) );
19 }
20 }
figure 4.43
Using a local class to hide the OrderRectByWidth class declaration further