java.util
Interface SortedMap<K,V>
- Map<K,V>
A map which guarantees its key's iteration order. The entries in the
map are related by the
natural ordering of the keys if they
are Comparable, or by the provided Comparator. Additional operations
take advantage of the sorted nature of the map.
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.
SortedMap | V> headMap(K toKey)- Returns a view of the portion of the map strictly less than toKey.
|
SortedMap | V> 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.
|
SortedMap | V> tailMap(K fromKey)- Returns a view of the portion of the map greater than or equal to
fromKey.
|
K | firstKey()- Returns the first (lowest sorted) key in the map.
|
K | lastKey()- Returns the last (highest sorted) key in the map.
|
Comparator | super K> comparator()- Returns the comparator used in sorting this map, or null if it is
the keys' natural ordering.
|
V>> entrySet, clear, containsKey, containsValue, equals, get, hashCode, isEmpty, keySet, put, putAll, remove, size, values |
V> headMap
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)).
toKey - the exclusive upper range of the submap
V> subMap
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.
fromKey - the inclusive lower range of the submaptoKey - the exclusive upper range of the submap
V> tailMap
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)).
fromKey - the inclusive lower range of the submap
firstKey
public K firstKey()
Returns the first (lowest sorted) key in the map.
lastKey
public K lastKey()
Returns the last (highest sorted) key in the map.
super K> comparator
public Comparatorsuper K> comparator()
Returns the comparator used in sorting this map, or null if it is
the keys' natural ordering.
SortedMap.java -- A map that makes guarantees about the order of its keys
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