Collections - Beginning Java 8 Language Features - page 575

Listing 12-32. Using a NavigableMap
// NavigableMapTest.java
package com.jdojo.collections;
import java.util.TreeMap;
import java.util.NavigableMap;
import java.util.Map.Entry;
public class NavigableMapTest {
public static void main(String[] args) {
// Create a sorted map sorted on string keys alphabetically
NavigableMap<String,String> nMap = new TreeMap<>();
nMap.put("John", "[phone]");
nMap.put("Richard", "[phone]");
nMap.put("Donna", "[phone]");
nMap.put("Ken", "[phone]");
System.out.println("Navigable Map:" + nMap);
// Get the closest lower and higher matches for Ken
Entry<String,String> lowerKen = nMap.lowerEntry("Ken");
Entry<String,String> floorKen = nMap.floorEntry("Ken");
Entry<String,String> higherKen = nMap.higherEntry("Ken");
Entry<String,String> ceilingKen = nMap.ceilingEntry("Ken");
System.out.println("Lower Ken: " + lowerKen);
System.out.println("Floor Ken: " + floorKen);
System.out.println("Higher Ken: " + higherKen);
System.out.println("Ceiling Ken: " + ceilingKen);
// Get the reverse order view of the map
NavigableMap<String,String> reverseMap = nMap.descendingMap();
System.out.println("Navigable Map(Reverse Order):" + reverseMap);
}
}
Navigable Map:{Donna=[phone], John=[phone], Ken=[phone], Richard=[phone]}
Lower Ken: John=[phone]
Floor Ken: Ken=[phone]
Higher Ken: Richard=[phone]
Ceiling Ken: Ken=[phone]
Navigable Map(Reverse Order):{Richard=[phone], Ken=[phone], John=[phone],
Donna=[phone]}