ConcurrentNavigableMap Interface

Quiz

A java.util.concurrent.ConcurrentNavigableMap interface is a subinterface of ConcurrentMap interface, and supports NavigableMap operations, and recursively so for its navigable sub-maps, and approximate matches.

ConcurrentMap Methods

Sr.No.	Method & Description
1	NavigableSet<K> descendingKeySet() Returns a reverse order NavigableSet view of the keys contained in this map.
2	ConcurrentNavigableMap<K,V> descendingMap() Returns a reverse order view of the mappings contained in this map.
3	ConcurrentNavigableMap<K,V> headMap(K toKey) Returns a view of the portion of this map whose keys are strictly less than toKey.
4	ConcurrentNavigableMap<K,V> headMap(K toKey, boolean inclusive) Returns a view of the portion of this map whose keys are less than (or equal to, if inclusive is true) toKey.
5	NavigableSet<K> keySet() Returns a NavigableSet view of the keys contained in this map.
6	NavigableSet<K> navigableKeySet() Returns a NavigableSet view of the keys contained in this map.
7	ConcurrentNavigableMap<K,V> subMap(K fromKey, boolean fromInclusive, K toKey, boolean toInclusive) Returns a view of the portion of this map whose keys range from fromKey to toKey.
8	ConcurrentNavigableMap<K,V> subMap(K fromKey, K toKey) Returns a view of the portion of this map whose keys range from fromKey, inclusive, to toKey, exclusive.
9	ConcurrentNavigableMap<K,V> tailMap(K fromKey) Returns a view of the portion of this map whose keys are greater than or equal to fromKey.
10	ConcurrentNavigableMap<K,V> tailMap(K fromKey, boolean inclusive) Returns a view of the portion of this map whose keys are greater than (or equal to, if inclusive is true) fromKey.

Example

The following TestThread program shows usage of ConcurrentNavigableMap.

import java.util.concurrent.ConcurrentNavigableMap;
import java.util.concurrent.ConcurrentSkipListMap;

public class TestThread {

   public static void main(final String[] arguments) {
      ConcurrentNavigableMap<String,String> map =
         new ConcurrentSkipListMap<String, String>();

      map.put("1", "One");
      map.put("2", "Two");
      map.put("3", "Three");
      map.put("5", "Five");
      map.put("6", "Six");

      System.out.println("Initial ConcurrentHashMap: "+map);
      System.out.println("HeadMap(\"2\") of ConcurrentHashMap: "+map.headMap("2"));
      System.out.println("TailMap(\"2\") of ConcurrentHashMap: "+map.tailMap("2"));
      System.out.println(
         "SubMap(\"2\", \"4\") of ConcurrentHashMap: "+map.subMap("2","4"));
   }  
}

This will produce the following result.

Output

Initial ConcurrentHashMap: {1 = One, 2 = Two, 3 = Three, 5 = Five, 6 = Six}
HeadMap("2") of ConcurrentHashMap: {1 = One}
TailMap("2") of ConcurrentHashMap: {2 = Two, 3 = Three, 5 = Five, 6 = Six}
SubMap("2", "4") of ConcurrentHashMap: {2 = Two, 3 = Three}

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