The NavigableMap interface was added by Java SE 6. It extends SortedMap and declares the behavior of a map that supports the retrieval of entries based on the closest match to a given key or keys. NavigableMap is a generic interface that has this declaration:
interface NavigableMap<K,V>
Here, K specifies the type of the keys, and V specifies the type of the values associated with the keys.
| Method | Description |
| Map.Entry<K,V> ceilingEntry(K obj) | Searches the map for the smallest key k such that k >= obj. If such a key |
| is found, its entry is returned. Otherwise, null is returned. | |
| K ceilingKey(K obj) | Searches the map for the smallest key k such that k >= obj. If such a key |
| is found, it is returned. Otherwise, null is returned. | |
| NavigableSet<K> descendingKeySet( ) | Returns a NavigableSet that contains the keys in the invoking map in |
| reverse order. Thus, it returns a reverse set-view of the keys. The | |
| resulting set is backed by the map. | |
| NavigableMap<K,V> descendingMap( ) | Returns a NavigableMap that is the reverse of the invoking map. The |
| resulting map is backed by the invoking map. | |
| Map.Entry<K,V> firstEntry( ) | Returns the first entry in the map. This is the entry with the least key. |
| Map.Entry<K,V> floorEntry(K obj) | Searches the map for the largest key k such that k <= obj. If such a key |
| is found, its entry is returned. Otherwise, null is returned. | |
| K floorKey(K obj) | Searches the map for the largest key k such that k <= obj. If such a key |
| is found, it is returned. Otherwise, null is returned. | |
| NavigableMap<K,V> | Returns a NavigableMap that includes all entries from the invoking map |
| headMap(K upperBound, boolean incl) | that have keys that are less than upperBound. If incl is true, then an |
| element equal to upperBound is included. The resulting map is backed by | |
| the invoking map. | |
| Map.Entry<K,V> higherEntry(K obj) | Searches the set for the largest key k such that k > obj. If such a key is |
| found, its entry is returned. Otherwise, null is returned. |
| Method | Description | |||
| K higherKey(K obj) | Searches the set for the largest key k such that k > obj. If such a key is | |||
| found, it is returned. Otherwise, null is returned. | ||||
| Map.Entry<K,V> lastEntry( ) | Returns the last entry in the map. This is the entry with the largest key. | |||
| Map.Entry<K,V> lowerEntry(K obj) | Searches the set for the largest key k such that k < obj. If such a key is | |||
| found, its entry is returned. Otherwise, null is returned. | ||||
| K lowerKey(K obj) | Searches the set for the largest key k such that k < obj. If such a key is | |||
| found, it is returned. Otherwise, null is returned. | ||||
| NavigableSet<K> navigableKeySet( ) | Returns a NavigableSet that contains the keys in the invoking map. The | |||
| resulting set is backed by the invoking map. | ||||
| Map.Entry<K,V> pollFirstEntry( ) | Returns the first entry, removing the entry in the process. Because the | |||
| map is sorted, this is the entry with the least key value. null is returned if | ||||
| the map is empty. | ||||
| Map.Entry<K,V> pollLastEntry( ) | Returns the last entry, removing the entry in the process. Because the | |||
| map is sorted, this is the entry with the greatest key value. null is | ||||
| returned if the map is empty. | ||||
| NavigableMap<K,V> | Returns a NavigableMap that includes all entries from the invoking map | |||
| subMap(K lowerBound, | that have keys that are greater than lowerBound and less than | |||
| boolean lowIncl, | upperBound. If lowIncl is true, then an element equal to lowerBound is | |||
| K upperBound | included. If highIncl is true, then an element equal to highIncl is included. | |||
| boolean highIncl) | The resulting map is backed by the invoking map. | |||
| NavigableMap<K,V> | Returns a NavigableMap that includes all entries from the invoking map | |||
| tailMap(K lowerBound, boolean incl) | that have keys that are greater than lowerBound. If incl is true, then an | |||
| element equal to lowerBound is included. The resulting map is backed by | ||||
| the invoking map. |