Added in API level 9

NavigableMap

interface NavigableMap<K : Any!, V : Any!> : SortedMap<K, V>

java.util.NavigableMap

Known Direct Subclasses ConcurrentNavigableMap, TreeMap ConcurrentNavigableMap A ConcurrentMap supporting NavigableMap operations, and recursively so for its navigable sub-maps. TreeMap A Red-Black tree based NavigableMap implementation.

Known Indirect Subclasses ConcurrentSkipListMap ConcurrentSkipListMap A scalable concurrent ConcurrentNavigableMap implementation.

A SortedMap extended with navigation methods returning the closest matches for given search targets. Methods lowerEntry, floorEntry, ceilingEntry, and higherEntry 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, floorKey, ceilingKey, and higherKey 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.

The methods ceilingEntry, firstEntry, floorEntry, higherEntry, lastEntry, lowerEntry, pollFirstEntry, and pollLastEntry return Map.Entry instances that represent snapshots of mappings as of the time of the call. They do not support mutation of the underlying map via the optional setValue method.

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.

Summary

Public methods
abstract MutableEntry<K, V>?	ceilingEntry(key: K) 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(key: K) 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 MutableEntry<K, V>?	firstEntry() Returns a key-value mapping associated with the least key in this map, or null if the map is empty.
abstract MutableEntry<K, V>?	floorEntry(key: K) 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(key: K) Returns the greatest key less than or equal to the given key, or null if there is no such key.
abstract NavigableMap<K, V>	headMap(toKey: K, inclusive: Boolean) Returns a view of the portion of this map whose keys are less than (or equal to, if inclusive is true) toKey.
abstract SortedMap<K, V>	headMap(toKey: K) Returns a view of the portion of this map whose keys are strictly less than toKey.
abstract MutableEntry<K, V>?	higherEntry(key: K) 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(key: K) Returns the least key strictly greater than the given key, or null if there is no such key.
abstract MutableEntry<K, V>?	lastEntry() Returns a key-value mapping associated with the greatest key in this map, or null if the map is empty.
abstract MutableEntry<K, V>?	lowerEntry(key: K) 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(key: K) 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 MutableEntry<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 MutableEntry<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.
open NavigableMap<K, V>	reversed() Returns a reverse-ordered view of this map.
abstract NavigableMap<K, V>	subMap(fromKey: K, fromInclusive: Boolean, toKey: K, toInclusive: Boolean) Returns a view of the portion of this map whose keys range from fromKey to toKey.
abstract SortedMap<K, V>	subMap(fromKey: K, toKey: K) Returns a view of the portion of this map whose keys range from fromKey, inclusive, to toKey, exclusive.
abstract NavigableMap<K, V>	tailMap(fromKey: K, inclusive: Boolean) 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(fromKey: K) Returns a view of the portion of this map whose keys are greater than or equal to fromKey.

Inherited functions
From class SortedMap Comparator<in K>? comparator() Returns the comparator used to order the keys in this map, or null if this map uses the natural ordering of its keys. K firstKey() Returns the first (lowest) key currently in this map. K lastKey() Returns the last (highest) key currently in this map. V? putFirst(k: K, v: V) Throws UnsupportedOperationException. The encounter order induced by this map's comparison method determines the position of mappings, so explicit positioning is not supported. V? putLast(k: K, v: V) Throws UnsupportedOperationException. The encounter order induced by this map's comparison method determines the position of mappings, so explicit positioning is not supported.
From class SequencedMap MutableEntry<K, V>! firstEntry() Returns the first key-value mapping in this map, or null if the map is empty. MutableEntry<K, V>! lastEntry() Returns the last key-value mapping in this map, or null if the map is empty. MutableEntry<K, V>! pollFirstEntry() Removes and returns the first key-value mapping in this map, or null if the map is empty (optional operation). MutableEntry<K, V>! pollLastEntry() Removes and returns the last key-value mapping in this map, or null if the map is empty (optional operation). SequencedSet<MutableEntry<K, V>!>! sequencedEntrySet() Returns a SequencedSet view of this map's entrySet. SequencedSet<K>! sequencedKeySet() Returns a SequencedSet view of this map's keySet. SequencedCollection<V>! sequencedValues() Returns a SequencedCollection view of this map's values collection.

Inherited properties

From class SortedMap MutableSet<MutableEntry<K, V>> entries Returns a Set view of the mappings contained in this map. The set's iterator returns the entries in ascending key order. The set is backed by the map, so changes to the map are reflected in the set, and vice-versa. If the map is modified while an iteration over the set is in progress (except through the iterator's own remove operation, or through the setValue operation on a map entry returned by the iterator) the results of the iteration are undefined. The set supports element removal, which removes the corresponding mapping from the map, via the Iterator.remove, Set.remove, removeAll, retainAll and clear operations. It does not support the add or addAll operations. MutableSet<K> keys Returns a Set view of the keys contained in this map. The set's iterator returns the keys in ascending order. The set is backed by the map, so changes to the map are reflected in the set, and vice-versa. If the map is modified while an iteration over the set is in progress (except through the iterator's own remove operation), the results of the iteration are undefined. The set supports element removal, which removes the corresponding mapping from the map, via the Iterator.remove, Set.remove, removeAll, retainAll, and clear operations. It does not support the add or addAll operations. MutableCollection<V> values Returns a Collection view of the values contained in this map. The collection's iterator returns the values in ascending order of the corresponding keys. The collection is backed by the map, so changes to the map are reflected in the collection, and vice-versa. If the map is modified while an iteration over the collection is in progress (except through the iterator's own remove operation), the results of the iteration are undefined. The collection supports element removal, which removes the corresponding mapping from the map, via the Iterator.remove, Collection.remove, removeAll, retainAll and clear operations. It does not support the add or addAll operations.

Public methods

ceilingEntry

Added in API level 9

abstract fun ceilingEntry(key: K): MutableEntry<K, V>?

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.

Parameters
key	K: the key

Return
MutableEntry<K, V>?	an entry with the least key greater than or equal to key, or null if there is no such key

Exceptions
java.lang.ClassCastException	if the specified key cannot be compared with the keys currently in the map
java.lang.NullPointerException	if the specified key is null and this map does not permit null keys

ceilingKey

Added in API level 9

abstract fun ceilingKey(key: K): K?

Returns the least key greater than or equal to the given key, or null if there is no such key.

Parameters
key	K: the key

Return
K?	the least key greater than or equal to key, or null if there is no such key

Exceptions
java.lang.ClassCastException	if the specified key cannot be compared with the keys currently in the map
java.lang.NullPointerException	if the specified key is null and this map does not permit null keys

descendingKeySet

Added in API level 9

abstract fun descendingKeySet(): NavigableSet<K>

Returns a reverse order NavigableSet view of the keys contained in this map. The set's iterator returns the keys in descending order. The set is backed by the map, so changes to the map are reflected in the set, and vice-versa. If the map is modified while an iteration over the set is in progress (except through the iterator's own remove operation), the results of the iteration are undefined. The set supports element removal, which removes the corresponding mapping from the map, via the Iterator.remove, Set.remove, removeAll, retainAll, and clear operations. It does not support the add or addAll operations.

Return
NavigableSet<K>	a reverse order navigable set view of the keys in this map

descendingMap

Added in API level 9

abstract fun descendingMap(): NavigableMap<K, V>

Returns a reverse order view of the mappings contained in this map. The descending map is backed by this map, so changes to the map are reflected in the descending map, and vice-versa. If either map is modified while an iteration over a collection view of either map is in progress (except through the iterator's own remove operation), the results of the iteration are undefined.

The returned map has an ordering equivalent to Collections.reverseOrder(comparator()). The expression m.descendingMap().descendingMap() returns a view of m essentially equivalent to m.

Return
NavigableMap<K, V>	a reverse order view of this map

firstEntry

Added in API level 9

abstract fun firstEntry(): MutableEntry<K, V>?

Returns a key-value mapping associated with the least key in this map, or null if the map is empty.

Return
MutableEntry<K, V>?	an entry with the least key, or null if this map is empty

floorEntry

Added in API level 9

abstract fun floorEntry(key: K): MutableEntry<K, V>?

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.

Parameters
key	K: the key

Return
MutableEntry<K, V>?	an entry with the greatest key less than or equal to key, or null if there is no such key

Exceptions
java.lang.ClassCastException	if the specified key cannot be compared with the keys currently in the map
java.lang.NullPointerException	if the specified key is null and this map does not permit null keys

floorKey

Added in API level 9

abstract fun floorKey(key: K): K?

Returns the greatest key less than or equal to the given key, or null if there is no such key.

Parameters
key	K: the key

Return
K?	the greatest key less than or equal to key, or null if there is no such key

Exceptions
java.lang.ClassCastException	if the specified key cannot be compared with the keys currently in the map
java.lang.NullPointerException	if the specified key is null and this map does not permit null keys

headMap

Added in API level 9

abstract fun headMap(
    toKey: K, 
    inclusive: Boolean
): NavigableMap<K, V>

Returns a view of the portion of this map whose keys are less than (or equal to, if inclusive is true) toKey. The returned map is backed by this map, so changes in the returned map are reflected in this map, and vice-versa. The returned map supports all optional map operations that this map supports.

The returned map will throw an IllegalArgumentException on an attempt to insert a key outside its range.

Parameters
toKey	K: high endpoint of the keys in the returned map
inclusive	Boolean: true if the high endpoint is to be included in the returned view

Return
NavigableMap<K, V>	a view of the portion of this map whose keys are less than (or equal to, if inclusive is true) toKey

Exceptions
java.lang.ClassCastException	if toKey is not compatible with this map's comparator (or, if the map has no comparator, if toKey does not implement Comparable). Implementations may, but are not required to, throw this exception if toKey cannot be compared to keys currently in the map.
java.lang.NullPointerException	if toKey is null and this map does not permit null keys
java.lang.IllegalArgumentException	if this map itself has a restricted range, and toKey lies outside the bounds of the range

headMap

Added in API level 9

abstract fun headMap(toKey: K): SortedMap<K, V>

Returns a view of the portion of this map whose keys are strictly less than toKey. The returned map is backed by this map, so changes in the returned map are reflected in this map, and vice-versa. The returned map supports all optional map operations that this map supports.

The returned map will throw an IllegalArgumentException on an attempt to insert a key outside its range.

Equivalent to headMap(toKey, false).

Parameters
toKey	K: high endpoint (exclusive) of the keys in the returned map

Return
SortedMap<K, V>	a view of the portion of this map whose keys are strictly less than toKey

Exceptions
java.lang.ClassCastException	if toKey is not compatible with this map's comparator (or, if the map has no comparator, if toKey does not implement Comparable). Implementations may, but are not required to, throw this exception if toKey cannot be compared to keys currently in the map.
java.lang.NullPointerException	if toKey is null and this map does not permit null keys
java.lang.IllegalArgumentException	if this map itself has a restricted range, and toKey lies outside the bounds of the range

higherEntry

Added in API level 9

abstract fun higherEntry(key: K): MutableEntry<K, V>?

Returns a key-value mapping associated with the least key strictly greater than the given key, or null if there is no such key.

Parameters
key	K: the key

Return
MutableEntry<K, V>?	an entry with the least key greater than key, or null if there is no such key

Exceptions
java.lang.ClassCastException	if the specified key cannot be compared with the keys currently in the map
java.lang.NullPointerException	if the specified key is null and this map does not permit null keys

higherKey

Added in API level 9

abstract fun higherKey(key: K): K?

Returns the least key strictly greater than the given key, or null if there is no such key.

Parameters
key	K: the key

Return
K?	the least key greater than key, or null if there is no such key

Exceptions
java.lang.ClassCastException	if the specified key cannot be compared with the keys currently in the map
java.lang.NullPointerException	if the specified key is null and this map does not permit null keys

lastEntry

Added in API level 9

abstract fun lastEntry(): MutableEntry<K, V>?

Returns a key-value mapping associated with the greatest key in this map, or null if the map is empty.

Return
MutableEntry<K, V>?	an entry with the greatest key, or null if this map is empty

lowerEntry

Added in API level 9

abstract fun lowerEntry(key: K): MutableEntry<K, V>?

Returns a key-value mapping associated with the greatest key strictly less than the given key, or null if there is no such key.

Parameters
key	K: the key

Return
MutableEntry<K, V>?	an entry with the greatest key less than key, or null if there is no such key

Exceptions
java.lang.ClassCastException	if the specified key cannot be compared with the keys currently in the map
java.lang.NullPointerException	if the specified key is null and this map does not permit null keys

lowerKey

Added in API level 9

abstract fun lowerKey(key: K): K?

Returns the greatest key strictly less than the given key, or null if there is no such key.

Parameters
key	K: the key

Return
K?	the greatest key less than key, or null if there is no such key

Exceptions
java.lang.ClassCastException	if the specified key cannot be compared with the keys currently in the map
java.lang.NullPointerException	if the specified key is null and this map does not permit null keys

navigableKeySet

Added in API level 9

abstract fun navigableKeySet(): NavigableSet<K>

Returns a NavigableSet view of the keys contained in this map. The set's iterator returns the keys in ascending order. The set is backed by the map, so changes to the map are reflected in the set, and vice-versa. If the map is modified while an iteration over the set is in progress (except through the iterator's own remove operation), the results of the iteration are undefined. The set supports element removal, which removes the corresponding mapping from the map, via the Iterator.remove, Set.remove, removeAll, retainAll, and clear operations. It does not support the add or addAll operations.

Return
NavigableSet<K>	a navigable set view of the keys in this map

pollFirstEntry

Added in API level 9

abstract fun pollFirstEntry(): MutableEntry<K, V>?

Removes and returns a key-value mapping associated with the least key in this map, or null if the map is empty.

Return
MutableEntry<K, V>?	the removed first entry of this map, or null if this map is empty

Exceptions
java.lang.UnsupportedOperationException	if this collection implementation does not support this operation

pollLastEntry

Added in API level 9

abstract fun pollLastEntry(): MutableEntry<K, V>?

Removes and returns a key-value mapping associated with the greatest key in this map, or null if the map is empty.

Return
MutableEntry<K, V>?	the removed last entry of this map, or null if this map is empty

Exceptions
java.lang.UnsupportedOperationException	if this collection implementation does not support this operation

reversed

Added in API level VanillaIceCream

open fun reversed(): NavigableMap<K, V>

Returns a reverse-ordered view of this map. The encounter order of mappings in the returned view is the inverse of the encounter order of mappings in this map. The reverse ordering affects all order-sensitive operations, including those on the view collections of the returned view. If the implementation permits modifications to this view, the modifications "write through" to the underlying map. Changes to the underlying map might or might not be visible in this reversed view, depending upon the implementation.

This method is equivalent to descendingMap.

Return
NavigableMap<K, V>	a reverse-ordered view of this map, as a NavigableMap

subMap

Added in API level 9

abstract fun subMap(
    fromKey: K, 
    fromInclusive: Boolean, 
    toKey: K, 
    toInclusive: Boolean
): NavigableMap<K, V>

Returns a view of the portion of this map whose keys range from fromKey to toKey. If fromKey and toKey are equal, the returned map is empty unless fromInclusive and toInclusive are both true. The returned map is backed by this map, so changes in the returned map are reflected in this map, and vice-versa. The returned map supports all optional map operations that this map supports.

The returned map will throw an IllegalArgumentException on an attempt to insert a key outside of its range, or to construct a submap either of whose endpoints lie outside its range.

Parameters
fromKey	K: low endpoint of the keys in the returned map
fromInclusive	Boolean: true if the low endpoint is to be included in the returned view
toKey	K: high endpoint of the keys in the returned map
toInclusive	Boolean: true if the high endpoint is to be included in the returned view

Return
NavigableMap<K, V>	a view of the portion of this map whose keys range from fromKey to toKey

Exceptions
java.lang.ClassCastException	if fromKey and toKey cannot be compared to one another using this map's comparator (or, if the map has no comparator, using natural ordering). Implementations may, but are not required to, throw this exception if fromKey or toKey cannot be compared to keys currently in the map.
java.lang.NullPointerException	if fromKey or toKey is null and this map does not permit null keys
java.lang.IllegalArgumentException	if fromKey is greater than toKey; or if this map itself has a restricted range, and fromKey or toKey lies outside the bounds of the range

subMap

Added in API level 9

abstract fun subMap(
    fromKey: K, 
    toKey: K
): SortedMap<K, V>

Returns a view of the portion of this map whose keys range from fromKey, inclusive, to toKey, exclusive. (If fromKey and toKey are equal, the returned map is empty.) The returned map is backed by this map, so changes in the returned map are reflected in this map, and vice-versa. The returned map supports all optional map operations that this map supports.

The returned map will throw an IllegalArgumentException on an attempt to insert a key outside its range.

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

Parameters
fromKey	K: low endpoint (inclusive) of the keys in the returned map
toKey	K: high endpoint (exclusive) of the keys in the returned map

Return
SortedMap<K, V>	a view of the portion of this map whose keys range from fromKey, inclusive, to toKey, exclusive

Exceptions
java.lang.ClassCastException	if fromKey and toKey cannot be compared to one another using this map's comparator (or, if the map has no comparator, using natural ordering). Implementations may, but are not required to, throw this exception if fromKey or toKey cannot be compared to keys currently in the map.
java.lang.NullPointerException	if fromKey or toKey is null and this map does not permit null keys
java.lang.IllegalArgumentException	if fromKey is greater than toKey; or if this map itself has a restricted range, and fromKey or toKey lies outside the bounds of the range

tailMap

Added in API level 9

abstract fun tailMap(
    fromKey: K, 
    inclusive: Boolean
): NavigableMap<K, V>

Returns a view of the portion of this map whose keys are greater than (or equal to, if inclusive is true) fromKey. The returned map is backed by this map, so changes in the returned map are reflected in this map, and vice-versa. The returned map supports all optional map operations that this map supports.

The returned map will throw an IllegalArgumentException on an attempt to insert a key outside its range.

Parameters
fromKey	K: low endpoint of the keys in the returned map
inclusive	Boolean: true if the low endpoint is to be included in the returned view

Return
NavigableMap<K, V>	a view of the portion of this map whose keys are greater than (or equal to, if inclusive is true) fromKey

Exceptions
java.lang.ClassCastException	if fromKey is not compatible with this map's comparator (or, if the map has no comparator, if fromKey does not implement Comparable). Implementations may, but are not required to, throw this exception if fromKey cannot be compared to keys currently in the map.
java.lang.NullPointerException	if fromKey is null and this map does not permit null keys
java.lang.IllegalArgumentException	if this map itself has a restricted range, and fromKey lies outside the bounds of the range

tailMap

Added in API level 9

abstract fun tailMap(fromKey: K): SortedMap<K, V>

Returns a view of the portion of this map whose keys are greater than or equal to fromKey. The returned map is backed by this map, so changes in the returned map are reflected in this map, and vice-versa. The returned map supports all optional map operations that this map supports.

The returned map will throw an IllegalArgumentException on an attempt to insert a key outside its range.

Equivalent to tailMap(fromKey, true).

Parameters
fromKey	K: low endpoint (inclusive) of the keys in the returned map

Return
SortedMap<K, V>	a view of the portion of this map whose keys are greater than or equal to fromKey

Exceptions
java.lang.ClassCastException	if fromKey is not compatible with this map's comparator (or, if the map has no comparator, if fromKey does not implement Comparable). Implementations may, but are not required to, throw this exception if fromKey cannot be compared to keys currently in the map.
java.lang.NullPointerException	if fromKey is null and this map does not permit null keys
java.lang.IllegalArgumentException	if this map itself has a restricted range, and fromKey lies outside the bounds of the range