OnJava8-Examples/collectiontopics/SortedMapDemo.java

// collectiontopics/SortedMapDemo.java
// (c)2021 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.
// What you can do with a TreeMap
import java.util.*;
import onjava.*;

public class SortedMapDemo {
  public static void main(String[] args) {
    TreeMap<Integer,String> sortedMap =
      new TreeMap<>(new CountMap(10));
    System.out.println(sortedMap);
    Integer low = sortedMap.firstKey();
    Integer high = sortedMap.lastKey();
    System.out.println(low);
    System.out.println(high);
    Iterator<Integer> it =
      sortedMap.keySet().iterator();
    for(int i = 0; i <= 6; i++) {
      if(i == 3) low = it.next();
      if(i == 6) high = it.next();
      else it.next();
    }
    System.out.println(low);
    System.out.println(high);
    System.out.println(sortedMap.subMap(low, high));
    System.out.println(sortedMap.headMap(high));
    System.out.println(sortedMap.tailMap(low));
  }
}
/* Output:
{0=A0, 1=B0, 2=C0, 3=D0, 4=E0, 5=F0, 6=G0, 7=H0, 8=I0,
9=J0}
0
9
3
7
{3=D0, 4=E0, 5=F0, 6=G0}
{0=A0, 1=B0, 2=C0, 3=D0, 4=E0, 5=F0, 6=G0}
{3=D0, 4=E0, 5=F0, 6=G0, 7=H0, 8=I0, 9=J0}
*/