Name
TreeMap<K,V>
Synopsis
This class
implements the SortedMap
interface using an
internal Red-Black tree data structure and guarantees that the keys
and values of the mapping can be enumerated in ascending order of
keys. TreeMap
supports all optional
Map
methods. The objects used as keys in a
TreeMap
must all be mutually
Comparable
, or an appropriate
Comparator
must be provided when the
TreeMap
is created. Because
TreeMap
is based on a binary tree data structure,
the get( )
, put( )
,
remove( )
, and containsKey( )
methods operate in relatively efficient logarithmic time. If you do
not need the sorting capability of TreeMap
,
however, use HashMap
instead, as it is even more
efficient. See Map
and
SortedMap
for details on the methods of
TreeMap
. See also the related
TreeSet
class.
In order for a
TreeMap
to work correctly, the comparison method
from the Comparable
or
Comparator
interface must be consistent with the
equals( )
method. That is, the equals(
)
method must compare two objects as equal if and only if
the comparison method also indicates those two objects are equal.
The methods of TreeMap
are not
synchronized
. If you are working in a
multithreaded environment, you must explicitly synchronize all code
that modifies the TreeMap
, or obtain a
synchronized wrapper with Collections.synchronizedMap(
)
.
Figure 16-63. java.util.TreeMap<K,V>
public class TreeMap<K,V> extends AbstractMap<K,V> ...
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