NavigableMap
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, .headMap, and .tailMap 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 Map.Entry.setValue method.
Methods .subMap, .headMap, and .tailMap 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.
This interface is a member of the {@docRoot}/java.base/java/util/package-summary.html#CollectionsFramework.
Author
Doug Lea
Josh Bloch
Since
1.6
Parameters
Inheritors
Properties
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.
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.
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.
Functions
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.
Returns the least key greater than or equal to the given key, or null if there is no such key.
Returns the comparator used to order the keys in this map, or null if this map uses the natural ordering of its keys.
ported from java.util.Map.computeIfAbsent()
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.
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.
Returns a key-value mapping associated with the least key in this map, or null if the map is empty.
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.
{@inheritDoc}
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.
Returns a key-value mapping associated with the least key strictly greater than the given key, or null if there is no such 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.
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.
Removes and returns a key-value mapping associated with the least key in this map, or null if the map is empty (optional operation).
Removes and returns a key-value mapping associated with the greatest key in this map, or null if the map is empty (optional operation).
ported from java.util.Map.putIfAbsent()
{@inheritDoc}
{@inheritDoc}
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.
{@inheritDoc}
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.