Java TreeMap Tutorial with Example program



Class TreeMap

Type Parameters:
    K - the type of keys maintained by this map
    V - the type of mapped values
   
All Implemented Interfaces:

    Serializable, Cloneable, Map, NavigableMap, SortedMap

public class TreeMap
extends AbstractMap
implements NavigableMap, Cloneable, Serializable
{
//
}


Since:
    1.2
   
See Also:
    Map, HashMap, Hashtable, Comparable, Comparator, Collection, Serialized Form
   

Nested classes/interfaces inherited from class java.util.AbstractMap

AbstractMap.SimpleEntry, AbstractMap.SimpleImmutableEntry


Constructors summary
TreeMap()
    Constructs a new, empty tree map, using the natural ordering of its keys.
   
TreeMap(Comparator comparator)
    Constructs a new, empty tree map, ordered according to the given comparator.

TreeMap(Map m)
    Constructs a new tree map containing the same mappings as the given map, ordered according to the natural ordering of its keys.

TreeMap(SortedMap m)
    Constructs a new tree map containing the same mappings and using the same ordering as the specified sorted map.

Methods summary

Map.Entry 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.
   
void clear()
    Removes all of the mappings from this map.
   
Object clone()
    Returns a shallow copy of this TreeMap instance.
   
Comparator comparator()
    Returns the comparator used to order the keys in this map, or null if this map uses the natural ordering of its keys.
   
boolean containsKey(Object key)
    Returns true if this map contains a mapping for the specified key.
   
boolean containsValue(Object value)
    Returns true if this map maps one or more keys to the specified value.
   
NavigableSet descendingKeySet()
    Returns a reverse order NavigableSet view of the keys contained in this map.
   
NavigableMap descendingMap()
    Returns a reverse order view of the mappings contained in this map.
   
Set entrySet()
    Returns a Set view of the mappings contained in this map.
   

Map.Entry firstEntry()
    Returns a key-value mapping associated with the least key in this map, or null if the map is empty.
   
K firstKey()
    Returns the first (lowest) key currently in this map.
   
Map.Entry    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.
   
V    get(Object key)
    Returns the value to which the specified key is mapped, or null if this map contains no mapping for the key.
   
SortedMap    headMap(K toKey)
    Returns a view of the portion of this map whose keys are strictly less than toKey.
   
NavigableMap    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    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.

Set    keySet()
    Returns a Set view of the keys contained in this map.

Map.Entry    lastEntry()
    Returns a key-value mapping associated with the greatest key in this map, or null if the map is empty.

K    lastKey()
    Returns the last (highest) key currently in this map.

Map.Entry 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 navigableKeySet()
    Returns a NavigableSet view of the keys contained in this map.

Map.Entry 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 pollLastEntry()
    Removes and returns a key-value mapping associated with the greatest key in this map, or null if the map is empty.

V put(K key, V value)
    Associates the specified value with the specified key in this map.

void putAll(Map map)

    Copies all of the mappings from the specified map to this map.

V remove(Object key)
    Removes the mapping for this key from this TreeMap if present.

int size()
    Returns the number of key-value mappings in this map.

NavigableMap subMap(K fromKey, boolean fromInclusive, K toKey, boolean toInclusive)
    Returns a view of the portion of this map whose keys range from fromKey to toKey.

SortedMap subMap(K fromKey, K toKey)
    Returns a view of the portion of this map whose keys range from fromKey, inclusive, to toKey, exclusive.

SortedMap tailMap(K fromKey)
    Returns a view of the portion of this map whose keys are greater than or equal to fromKey.

NavigableMap 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.

Collection values()
    Returns a Collection view of the values contained in this map.

Methods inherited from class java.util.AbstractMap

public boolean isEmpty()
    Returns true if this map contains no key-value mappings.
    This implementation returns size() == 0.
   
Methods inherited from class java.lang.Object
    finalize, getClass, notify, notifyAll, wait, wait, wait,equals, hashCode, toString




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