K - the type of keys maintained by this mapV - the type of mapped valuespublic interfaceNavigableMap<K,V>extendsSortedMap<K,V>
SortedMap extended with navigation methods returning the closest matches for given search targets. MethodslowerEntry,floorEntry,ceilingEntry, andhigherEntry returnMap.Entry objects associated with keys respectively less than, less than or equal, greater than or equal, and greater than a given key, returningnull if there is no such key. Similarly, methodslowerKey,floorKey,ceilingKey, andhigherKey return only the associated keys. All of these methods are designed for locating, not traversing entries.ANavigableMap may be accessed and traversed in either ascending or descending key order. ThedescendingMap 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. MethodssubMap,headMap, andtailMap differ from the like-namedSortedMap methods in accepting additional arguments describing whether lower and upper bounds are inclusive versus exclusive. Submaps of anyNavigableMap must implement theNavigableMap interface.
This interface additionally defines methodsfirstEntry,pollFirstEntry,lastEntry, andpollLastEntry that return and/or remove the least and greatest mappings, if any exist, else returningnull.
Implementations of entry-returning methods are expected to returnMap.Entry pairs representing snapshots of mappings at the time they were produced, and thus generally donot support the optionalEntry.setValue method. Note however that it is possible to change mappings in the associated map using methodput.
MethodssubMap(K, K),headMap(K), andtailMap(K) are specified to returnSortedMap to allow existing implementations ofSortedMap to be compatibly retrofitted to implementNavigableMap, but extensions and implementations of this interface are encouraged to override these methods to returnNavigableMap. Similarly,SortedMap.keySet() can be overriden to returnNavigableSet.
This interface is a member of the Java Collections Framework.
| Modifier and Type | Method and Description |
|---|---|
Map.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. |
K | ceilingKey(K key)Returns the least key greater than or equal to the given key, or null if there is no such key. |
NavigableSet<K> | descendingKeySet()Returns a reverse order NavigableSet view of the keys contained in this map. |
NavigableMap<K,V> | descendingMap()Returns a reverse order view of the mappings contained in this map. |
Map.Entry<K,V> | firstEntry()Returns a key-value mapping associated with the least key in this map, or null if the map is empty. |
Map.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. |
K | floorKey(K key)Returns the greatest key less than or equal to the given key, or null if there is no such key. |
SortedMap<K,V> | headMap(K toKey)Returns a view of the portion of this map whose keys are strictly less than toKey. |
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. |
Map.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. |
K | higherKey(K key)Returns the least key strictly greater than the given key, or null if there is no such key. |
Map.Entry<K,V> | lastEntry()Returns a key-value mapping associated with the greatest key in this map, or null if the map is empty. |
Map.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. |
K | lowerKey(K key)Returns the greatest key strictly less than the given key, or null if there is no such key. |
NavigableSet<K> | navigableKeySet()Returns a NavigableSet view of the keys contained in this map. |
Map.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. |
Map.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. |
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 totoKey. |
SortedMap<K,V> | subMap(K fromKey,K toKey)Returns a view of the portion of this map whose keys range from fromKey, inclusive, totoKey, exclusive. |
SortedMap<K,V> | tailMap(K fromKey)Returns a view of the portion of this map whose keys are greater than or equal to fromKey. |
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. |
Map.Entry<K,V> lowerEntry(K key)
null if there is no such key.key - the keykey, ornull if there is no such keyClassCastException - if the specified key cannot be compared with the keys currently in the mapNullPointerException - if the specified key is null and this map does not permit null keysK lowerKey(K key)
null if there is no such key.key - the keykey, ornull if there is no such keyClassCastException - if the specified key cannot be compared with the keys currently in the mapNullPointerException - if the specified key is null and this map does not permit null keysMap.Entry<K,V> floorEntry(K key)
null if there is no such key.key - the keykey, ornull if there is no such keyClassCastException - if the specified key cannot be compared with the keys currently in the mapNullPointerException - if the specified key is null and this map does not permit null keysK floorKey(K key)
null if there is no such key.key - the keykey, ornull if there is no such keyClassCastException - if the specified key cannot be compared with the keys currently in the mapNullPointerException - if the specified key is null and this map does not permit null keysMap.Entry<K,V> ceilingEntry(K key)
null if there is no such key.key - the keykey, ornull if there is no such keyClassCastException - if the specified key cannot be compared with the keys currently in the mapNullPointerException - if the specified key is null and this map does not permit null keysK ceilingKey(K key)
null if there is no such key.key - the keykey, ornull if there is no such keyClassCastException - if the specified key cannot be compared with the keys currently in the mapNullPointerException - if the specified key is null and this map does not permit null keysMap.Entry<K,V> higherEntry(K key)
null if there is no such key.key - the keykey, ornull if there is no such keyClassCastException - if the specified key cannot be compared with the keys currently in the mapNullPointerException - if the specified key is null and this map does not permit null keysK higherKey(K key)
null if there is no such key.key - the keykey, ornull if there is no such keyClassCastException - if the specified key cannot be compared with the keys currently in the mapNullPointerException - if the specified key is null and this map does not permit null keysMap.Entry<K,V> firstEntry()
null if the map is empty.null if this map is emptyMap.Entry<K,V> lastEntry()
null if the map is empty.null if this map is emptyMap.Entry<K,V> pollFirstEntry()
null if the map is empty.null if this map is emptyMap.Entry<K,V> pollLastEntry()
null if the map is empty.null if this map is emptyNavigableMap<K,V> descendingMap()
remove operation), the results of the iteration are undefined.The returned map has an ordering equivalent toCollections.reverseOrder(comparator()). The expressionm.descendingMap().descendingMap() returns a view ofm essentially equivalent tom.
NavigableSet<K> navigableKeySet()
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 ownremove operation), the results of the iteration are undefined. The set supports element removal, which removes the corresponding mapping from the map, via theIterator.remove,Set.remove,removeAll,retainAll, andclear operations. It does not support theadd oraddAll operations.NavigableSet<K> descendingKeySet()
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 ownremove operation), the results of the iteration are undefined. The set supports element removal, which removes the corresponding mapping from the map, via theIterator.remove,Set.remove,removeAll,retainAll, andclear operations. It does not support theadd oraddAll operations.NavigableMap<K,V> subMap(K fromKey, boolean fromInclusive,K toKey, boolean toInclusive)
fromKey totoKey. IffromKey andtoKey are equal, the returned map is empty unlessfromInclusive andtoInclusive 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 anIllegalArgumentException on an attempt to insert a key outside of its range, or to construct a submap either of whose endpoints lie outside its range.
fromKey - low endpoint of the keys in the returned mapfromInclusive -true if the low endpoint is to be included in the returned viewtoKey - high endpoint of the keys in the returned maptoInclusive -true if the high endpoint is to be included in the returned viewfromKey totoKeyClassCastException - iffromKey andtoKey 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 iffromKey ortoKey cannot be compared to keys currently in the map.NullPointerException - iffromKey ortoKey is null and this map does not permit null keysIllegalArgumentException - iffromKey is greater thantoKey; or if this map itself has a restricted range, andfromKey ortoKey lies outside the bounds of the rangeNavigableMap<K,V> headMap(K toKey, boolean inclusive)
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 anIllegalArgumentException on an attempt to insert a key outside its range.
toKey - high endpoint of the keys in the returned mapinclusive -true if the high endpoint is to be included in the returned viewinclusive is true)toKeyClassCastException - iftoKey is not compatible with this map's comparator (or, if the map has no comparator, iftoKey does not implementComparable). Implementations may, but are not required to, throw this exception iftoKey cannot be compared to keys currently in the map.NullPointerException - iftoKey is null and this map does not permit null keysIllegalArgumentException - if this map itself has a restricted range, andtoKey lies outside the bounds of the rangeNavigableMap<K,V> tailMap(K fromKey, boolean inclusive)
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 anIllegalArgumentException on an attempt to insert a key outside its range.
fromKey - low endpoint of the keys in the returned mapinclusive -true if the low endpoint is to be included in the returned viewinclusive is true)fromKeyClassCastException - iffromKey is not compatible with this map's comparator (or, if the map has no comparator, iffromKey does not implementComparable). Implementations may, but are not required to, throw this exception iffromKey cannot be compared to keys currently in the map.NullPointerException - iffromKey is null and this map does not permit null keysIllegalArgumentException - if this map itself has a restricted range, andfromKey lies outside the bounds of the rangeSortedMap<K,V> subMap(K fromKey,K toKey)
fromKey, inclusive, totoKey, exclusive. (IffromKey andtoKey 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 anIllegalArgumentException on an attempt to insert a key outside its range.
Equivalent tosubMap(fromKey, true, toKey, false).
subMap in interface SortedMap<K,V>fromKey - low endpoint (inclusive) of the keys in the returned maptoKey - high endpoint (exclusive) of the keys in the returned mapfromKey, inclusive, totoKey, exclusiveClassCastException - iffromKey andtoKey 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 iffromKey ortoKey cannot be compared to keys currently in the map.NullPointerException - iffromKey ortoKey is null and this map does not permit null keysIllegalArgumentException - iffromKey is greater thantoKey; or if this map itself has a restricted range, andfromKey ortoKey lies outside the bounds of the rangeSortedMap<K,V> headMap(K toKey)
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 anIllegalArgumentException on an attempt to insert a key outside its range.
Equivalent toheadMap(toKey, false).
headMap in interface SortedMap<K,V>toKey - high endpoint (exclusive) of the keys in the returned maptoKeyClassCastException - iftoKey is not compatible with this map's comparator (or, if the map has no comparator, iftoKey does not implementComparable). Implementations may, but are not required to, throw this exception iftoKey cannot be compared to keys currently in the map.NullPointerException - iftoKey is null and this map does not permit null keysIllegalArgumentException - if this map itself has a restricted range, andtoKey lies outside the bounds of the rangeSortedMap<K,V> tailMap(K fromKey)
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 anIllegalArgumentException on an attempt to insert a key outside its range.
Equivalent totailMap(fromKey, true).
tailMap in interface SortedMap<K,V>fromKey - low endpoint (inclusive) of the keys in the returned mapfromKeyClassCastException - iffromKey is not compatible with this map's comparator (or, if the map has no comparator, iffromKey does not implementComparable). Implementations may, but are not required to, throw this exception iffromKey cannot be compared to keys currently in the map.NullPointerException - iffromKey is null and this map does not permit null keysIllegalArgumentException - if this map itself has a restricted range, andfromKey lies outside the bounds of the range