NavigableMap

public interface NavigableMap implements SortedMap<K, V>
Known Indirect Subclasses

A SortedMap extended with navigation methods returning the closest matches for given search targets. Methods lowerEntry(K), floorEntry(K), ceilingEntry(K), and higherEntry(K) return Map.Entry objects associated with keys respectively less than, less than or equal, greater than or equal, and greater than a given key, returning null if there is no such key. Similarly, methods lowerKey(K), floorKey(K), ceilingKey(K), and higherKey(K) return only the associated keys. All of these methods are designed for locating, not traversing entries.

A NavigableMap may be accessed and traversed in either ascending or descending key order. The descendingMap() method returns a view of the map with the senses of all relational and directional methods inverted. The performance of ascending operations and views is likely to be faster than that of descending ones. Methods subMap(K, boolean, K, boolean), headMap(K, boolean), and tailMap(K, boolean) differ from the like-named SortedMap methods in accepting additional arguments describing whether lower and upper bounds are inclusive versus exclusive. Submaps of any NavigableMap must implement the NavigableMap interface.

This interface additionally defines methods firstEntry(), pollFirstEntry(), lastEntry(), and pollLastEntry() that return and/or remove the least and greatest mappings, if any exist, else returning null.

Implementations of entry-returning methods are expected to return Map.Entry pairs representing snapshots of mappings at the time they were produced, and thus generally do not support the optional Entry.setValue method. Note however that it is possible to change mappings in the associated map using method put.

Methods subMap(K, K), headMap(K), and tailMap(K) are specified to return SortedMap to allow existing implementations of SortedMap to be compatibly retrofitted to implement NavigableMap, but extensions and implementations of this interface are encouraged to override these methods to return NavigableMap. Similarly, keySet() can be overridden to return NavigableSet.

Public Method Summary

abstract Entry<K, V>
ceilingEntry(K key)
Returns a key-value mapping associated with the least key greater than or equal to the given key, or null if there is no such key.
abstract K
ceilingKey(K key)
Returns the least key greater than or equal to the given key, or null if there is no such key.
abstract NavigableSet<K>
descendingKeySet()
Returns a reverse order NavigableSet view of the keys contained in this map.
abstract NavigableMap<K, V>
descendingMap()
Returns a reverse order view of the mappings contained in this map.
abstract Entry<K, V>
firstEntry()
Returns a key-value mapping associated with the least key in this map, or null if the map is empty.
abstract Entry<K, V>
floorEntry(K key)
Returns a key-value mapping associated with the greatest key less than or equal to the given key, or null if there is no such key.
abstract K
floorKey(K key)
Returns the greatest key less than or equal to the given key, or null if there is no such key.
abstract SortedMap<K, V>
headMap(K toKey)
Returns a view of the portion of this map whose keys are strictly less than toKey.

Equivalent to headMap(toKey, false).

abstract NavigableMap<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.
abstract Entry<K, V>
higherEntry(K key)
Returns a key-value mapping associated with the least key strictly greater than the given key, or null if there is no such key.
abstract K
higherKey(K key)
Returns the least key strictly greater than the given key, or null if there is no such key.
abstract Entry<K, V>
lastEntry()
Returns a key-value mapping associated with the greatest key in this map, or null if the map is empty.
abstract Entry<K, V>
lowerEntry(K key)
Returns a key-value mapping associated with the greatest key strictly less than the given key, or null if there is no such key.
abstract K
lowerKey(K key)
Returns the greatest key strictly less than the given key, or null if there is no such key.
abstract NavigableSet<K>
navigableKeySet()
Returns a NavigableSet view of the keys contained in this map.
abstract Entry<K, V>
pollFirstEntry()
Removes and returns a key-value mapping associated with the least key in this map, or null if the map is empty.
abstract Entry<K, V>
pollLastEntry()
Removes and returns a key-value mapping associated with the greatest key in this map, or null if the map is empty.
abstract SortedMap<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.

Equivalent to subMap(fromKey, true, toKey, false).

abstract NavigableMap<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.
abstract NavigableMap<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.
abstract SortedMap<K, V>
tailMap(K fromKey)
Returns a view of the portion of this map whose keys are greater than or equal to fromKey.

Equivalent to tailMap(fromKey, true).

Inherited Method Summary