TreeMapK,V

TreeMap<K,V>

java.util

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Java 1.2

cloneable serializable collection

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> implements SortedMap<K,V>,        Cloneable, Serializable {  // Public Constructors  public  TreeMap  ( );        public  TreeMap  (Comparator<? super K>  c  );        public  TreeMap  (SortedMap<K,? extends V>  m  );        public  TreeMap  (Map<? extends K,? extends V>  m  );  // Methods Implementing Map  public void  clear  ( );        public boolean  containsKey  (Object  key  );        public boolean  containsValue  (Object  value  );        public Set<Map.Entry<K,V>>  entrySet  ( );        public V  get  (Object  key  );        public Set<K>  keySet  ( );        public V  put  (K  key  , V  value  );        public void  putAll  (Map<? extends K,? extends V>  map  );        public V  remove  (Object  key  );        public int  size  ( );        public Collection<V>  values  ( );  // Methods Implementing SortedMap  public Comparator<? super K>  comparator  ( );        public K  firstKey  ( );        public SortedMap<K,V>  headMap  (K  toKey  );        public K  lastKey  ( );        public SortedMap<K,V>  subMap  (K  fromKey  , K  toKey  );        public SortedMap<K,V>  tailMap  (K  fromKey  );  // Public Methods Overriding AbstractMap  public Object  clone  ( );   }