// interfaces/RandomStrings.java
// (c)2017 MindView LLC: see Copyright.txt
// We make no guarantees that this code is fit for any purpose.
// Visit http://OnJava8.com for more book information.
// Implementing an interface to conform to a method
import java.nio.*;
import java.util.*;

public class RandomStrings implements Readable {
  private static Random rand = new Random(47);
  private static final char[] CAPITALS =
    "ABCDEFGHIJKLMNOPQRSTUVWXYZ".toCharArray();
  private static final char[] LOWERS =
    "abcdefghijklmnopqrstuvwxyz".toCharArray();
  private static final char[] VOWELS =
    "aeiou".toCharArray();
  private int count;
  public RandomStrings(int count) {
    this.count = count;
  }
  @Override
  public int read(CharBuffer cb) {
    if(count-- == 0)
      return -1; // Indicates end of input
    cb.append(CAPITALS[rand.nextInt(CAPITALS.length)]);
    for(int i = 0; i < 4; i++) {
      cb.append(VOWELS[rand.nextInt(VOWELS.length)]);
      cb.append(LOWERS[rand.nextInt(LOWERS.length)]);
    }
    cb.append(" ");
    return 10; // Number of characters appended
  }
  public static void main(String[] args) {
    Scanner s = new Scanner(new RandomStrings(10));
    while(s.hasNext())
      System.out.println(s.next());
  }
}
/* Output:
Yazeruyac
Fowenucor
Goeazimom
Raeuuacio
Nuoadesiw
Hageaikux
Ruqicibui
Numasetih
Kuuuuozog
Waqizeyoy
*/