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public interface SortedMap<K,V>
extends Map<K,V>
All keys entered in the map must be mutually comparable; in other words,
k1.compareTo(k2)
or comparator.compare(k1, k2)
must not throw a ClassCastException. The ordering must be consistent
with equals (see Comparator
for this definition), if the
map is to obey the general contract of the Map interface. If not,
the results are well-defined, but probably not what you wanted.
It is recommended that all implementing classes provide four constructors: 1) one that takes no arguments and builds an empty map sorted by natural order of the keys; 2) one that takes a Comparator for the sorting order; 3) one that takes a Map and sorts according to the natural order of its keys; and 4) one that takes a SortedMap and sorts by the same comparator. Unfortunately, the Java language does not provide a way to enforce this.
Map
, TreeMap
, SortedSet
, Comparable
, Comparator
, Collection
, ClassCastException
Method Summary | |
SortedMap |
|
SortedMap |
|
SortedMap |
|
K |
|
K |
|
Comparator |
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Methods inherited from interface java.util.Map<K,V> | |
V>> entrySet , clear , containsKey , containsValue , equals , get , hashCode , isEmpty , keySet , put , putAll , remove , size , values |
public SortedMapV> headMap (K toKey)
Returns a view of the portion of the map strictly less than toKey. The view is backed by this map, so changes in one show up in the other. The submap supports all optional operations of the original.The returned map throws an IllegalArgumentException any time a key is used which is out of the range of toKey. Note that the endpoint, toKey, is not included; if you want this value to be included, pass its successor object in to toKey. For example, for Integers, you could request
headMap(new Integer(limit.intValue() + 1))
.
- Parameters:
toKey
- the exclusive upper range of the submap
- Returns:
- the submap
- Throws:
ClassCastException
- if toKey is not comparable to the map contentsIllegalArgumentException
- if this is a subMap, and toKey is out of rangeNullPointerException
- if toKey is null but the map does not allow null keys
public SortedMapV> subMap (K fromKey, K toKey)
Returns a view of the portion of the map greater than or equal to fromKey, and strictly less than toKey. The view is backed by this map, so changes in one show up in the other. The submap supports all optional operations of the original.The returned map throws an IllegalArgumentException any time a key is used which is out of the range of fromKey and toKey. Note that the lower endpoint is included, but the upper is not; if you want to change the inclusion or exclusion of an endpoint, pass its successor object in instead. For example, for Integers, you could request
subMap(new Integer(lowlimit.intValue() + 1), new Integer(highlimit.intValue() + 1))
to reverse the inclusiveness of both endpoints.
- Parameters:
fromKey
- the inclusive lower range of the submaptoKey
- the exclusive upper range of the submap
- Returns:
- the submap
- Throws:
ClassCastException
- if fromKey or toKey is not comparable to the map contentsIllegalArgumentException
- if this is a subMap, and fromKey or toKey is out of rangeNullPointerException
- if fromKey or toKey is null but the map does not allow null keys
public SortedMapV> tailMap (K fromKey)
Returns a view of the portion of the map greater than or equal to fromKey. The view is backed by this map, so changes in one show up in the other. The submap supports all optional operations of the original.The returned map throws an IllegalArgumentException any time a key is used which is out of the range of fromKey. Note that the endpoint, fromKey, is included; if you do not want this value to be included, pass its successor object in to fromKey. For example, for Integers, you could request
tailMap(new Integer(limit.intValue() + 1))
.
- Parameters:
fromKey
- the inclusive lower range of the submap
- Returns:
- the submap
- Throws:
ClassCastException
- if fromKey is not comparable to the map contentsIllegalArgumentException
- if this is a subMap, and fromKey is out of rangeNullPointerException
- if fromKey is null but the map does not allow null keys
public K firstKey()
Returns the first (lowest sorted) key in the map.
- Returns:
- the first key
- Throws:
NoSuchElementException
- if this map is empty.
public K lastKey()
Returns the last (highest sorted) key in the map.
- Returns:
- the last key
- Throws:
NoSuchElementException
- if this map is empty.
public Comparatorsuper K> comparator()
Returns the comparator used in sorting this map, or null if it is the keys' natural ordering.
- Returns:
- the sorting comparator