Generic Collections - Java: How to Program Early Objects - page 703

elements in a List with a specified value. The fill operation is useful for reinitializing a
List . Method copy takes two arguments—a destination List and a source List . Each
source List element is copied to the destination List . The destination List must be at
least as long as the source List ; otherwise, an IndexOutOfBoundsException occurs. If the
destination List is longer, the elements not overwritten are unchanged.
Each method we've seen so far operates on List s. Methods min and max each operate
on any Collection . Method min returns the smallest element in a Collection , and
method max returns the largest element in a Collection . Both of these methods can be
called with a Comparator object as a second argument to perform custom comparisons of
objects, such as the TimeComparator in Fig. 16.9. Figure 16.11 demonstrates methods
reverse , fill , copy , max and min .

1

// Fig. 16.11: Algorithms1.java

2

// Collections methods reverse, fill, copy, max and min.

3

import java.util.List;

4

import java.util.Arrays;

5

import java.util.Collections;

6
7

public class Algorithms1

8

{

9

public static void main(String[] args)

10

{

11 // create and display a List<Character>

12 Character[] letters = { 'P' , 'C' , 'M' };

13 List<Character> list = Arrays.asList(letters); // get List

14 System.out.println( "list contains: " );

15 output(list);

16
17 // reverse and display the List<Character>

18 Collections.reverse(list); // reverse order the elements

19 System.out.printf( "%nAfter calling reverse, list contains:%n" );

20 output(list);

21
22 // create copyList from an array of 3 Characters

23 Character[] lettersCopy = new Character[ 3 ];

24 List<Character> copyList = Arrays.asList(lettersCopy);

25
26 // copy the contents of list into copyList

27 Collections.copy(copyList, list);

28 System.out.printf( "%nAfter copying, copyList contains:%n" );

29 output(copyList);

30
31 // fill list with Rs

32 Collections.fill(list, 'R' );

33 System.out.printf( "%nAfter calling fill, list contains:%n" );

34 output(list);

35 }

36
37 // output List information

38 private static void output(List<Character> listRef)

39 {

Fig. 16.11 | Collections methods reverse , fill , copy , max and min . (Part 1 of 2.)