Android
java.util
public class

java.util.Hashtable<K, V>

java.lang.Object
java.util.Dictionary<K, V>
java.util.Hashtable<K, V> Serializable Cloneable Map<K, V>

Hashtable associates keys with values. Keys and values cannot be null. The size of the Hashtable is the number of key/value pairs it contains. The capacity is the number of key/value pairs the Hashtable can hold. The load factor is a float value which determines how full the Hashtable gets before expanding the capacity. If the load factor of the Hashtable is exceeded, the capacity is doubled.

Known Direct Subclasses
Known Indirect Subclasses

Summary

Public Constructors

            Hashtable()
Constructs a new Hashtable using the default capacity and load factor.
            Hashtable(int capacity)
Constructs a new Hashtable using the specified capacity and the default load factor.
            Hashtable(int capacity, float loadFactor)
Constructs a new Hashtable using the specified capacity and load factor.
            Hashtable(Map<? extends K, ? extends V> map)
Constructs a new instance of Hashtable containing the mappings from the specified Map.

Public Methods

  synchronized        void  clear()
Removes all key/value pairs from this Hashtable, leaving the size zero and the capacity unchanged.
  synchronized        Object  clone()
Returns a new Hashtable with the same key/value pairs, capacity and load factor.
  synchronized        boolean  contains(Object value)
Returns if this Hashtable contains the specified object as the value of at least one of the key/value pairs.
  synchronized        boolean  containsKey(Object key)
Returns if this Hashtable contains the specified object as a key of one of the key/value pairs.
          boolean  containsValue(Object value)
Searches this Hashtable for the specified value.
  synchronized        Enumeration<V>  elements()
Returns an Enumeration on the values of this Hashtable.
          Set<Entry<K, V>>  entrySet()
Returns a Set of the mappings contained in this Hashtable.
  synchronized        boolean  equals(Object object)
Compares the specified object to this Hashtable and answer if they are equal.
  synchronized        get(Object key)
Returns the value associated with the specified key in this Hashtable.
  synchronized        int  hashCode()
Returns an integer hash code for the receiver.
  synchronized        boolean  isEmpty()
Returns if this Hashtable has no key/value pairs, a size of zero.
          Set<K>  keySet()
Returns a Set of the keys contained in this Hashtable.
  synchronized        Enumeration<K>  keys()
Returns an Enumeration on the keys of this Hashtable.
  synchronized        put(K key, V value)
Associate the specified value with the specified key in this Hashtable.
  synchronized        void  putAll(Map<? extends K, ? extends V> map)
Copies every mapping in the specified Map to this Hashtable.
  synchronized        remove(Object key)
Remove the key/value pair with the specified key from this Hashtable.
  synchronized        int  size()
Returns the number of key/value pairs in this Hashtable.
  synchronized        String  toString()
Returns the string representation of this Hashtable.
          Collection<V>  values()
Returns a Collection of the values contained in this Hashtable.

Protected Methods

          void  rehash()
Increases the capacity of this Hashtable.
Methods inherited from class java.util.Dictionary
Methods inherited from class java.lang.Object
Methods inherited from interface java.util.Map

Details

Public Constructors

public Hashtable()

Constructs a new Hashtable using the default capacity and load factor.

public Hashtable(int capacity)

Constructs a new Hashtable using the specified capacity and the default load factor.

Parameters

capacity the initial capacity

public Hashtable(int capacity, float loadFactor)

Constructs a new Hashtable using the specified capacity and load factor.

Parameters

capacity the initial capacity
loadFactor the initial load factor

public Hashtable(Map<? extends K, ? extends V> map)

Constructs a new instance of Hashtable containing the mappings from the specified Map.

Parameters

map the mappings to add

Public Methods

public synchronized void clear()

Removes all key/value pairs from this Hashtable, leaving the size zero and the capacity unchanged.

See Also

public synchronized Object clone()

Returns a new Hashtable with the same key/value pairs, capacity and load factor.

Returns

  • a shallow copy of this Hashtable

See Also

public synchronized boolean contains(Object value)

Returns if this Hashtable contains the specified object as the value of at least one of the key/value pairs.

Parameters

value the object to look for as a value in this Hashtable

Returns

  • true if object is a value in this Hashtable, false otherwise

public synchronized boolean containsKey(Object key)

Returns if this Hashtable contains the specified object as a key of one of the key/value pairs.

Parameters

key the object to look for as a key in this Hashtable

Returns

  • true if object is a key in this Hashtable, false otherwise

public boolean containsValue(Object value)

Searches this Hashtable for the specified value.

Parameters

value the object to search for

Returns

  • true if value is a value of this Hashtable, false otherwise

public synchronized Enumeration<V> elements()

Returns an Enumeration on the values of this Hashtable. The results of the Enumeration may be affected if the contents of this Hashtable are modified.

Returns

  • an Enumeration of the values of this Hashtable

public Set<Entry<K, V>> entrySet()

Returns a Set of the mappings contained in this Hashtable. Each element in the set is a Map.Entry. The set is backed by this Hashtable so changes to one are reflected by the other. The set does not support adding.

Returns

  • a Set of the mappings

public synchronized boolean equals(Object object)

Compares the specified object to this Hashtable and answer if they are equal. The object must be an instance of Map and contain the same key/value pairs.

Parameters

object the object to compare with this object

Returns

  • true if the specified object is equal to this Map, false otherwise

See Also

public synchronized V get(Object key)

Returns the value associated with the specified key in this Hashtable.

Parameters

key the key of the value returned

Returns

  • the value associated with the specified key, null if the specified key does not exist

See Also

public synchronized int hashCode()

Returns an integer hash code for the receiver. Objects which are equal answer the same value for this method.

Returns

  • the receiver's hash

See Also

public synchronized boolean isEmpty()

Returns if this Hashtable has no key/value pairs, a size of zero.

Returns

  • true if this Hashtable has no key/value pairs, false otherwise

See Also

public Set<K> keySet()

Returns a Set of the keys contained in this Hashtable. The set is backed by this Hashtable so changes to one are reflected by the other. The set does not support adding.

Returns

  • a Set of the keys

public synchronized Enumeration<K> keys()

Returns an Enumeration on the keys of this Hashtable. The results of the Enumeration may be affected if the contents of this Hashtable are modified.

Returns

  • an Enumeration of the keys of this Hashtable

public synchronized V put(K key, V value)

Associate the specified value with the specified key in this Hashtable. If the key already exists, the old value is replaced. The key and value cannot be null.

Parameters

key the key to add
value the value to add

Returns

  • the old value associated with the specified key, null if the key did not exist

public synchronized void putAll(Map<? extends K, ? extends V> map)

Copies every mapping in the specified Map to this Hashtable.

Parameters

map the Map to copy mappings from

public synchronized V remove(Object key)

Remove the key/value pair with the specified key from this Hashtable.

Parameters

key the key to remove

Returns

  • the value associated with the specified key, null if the specified key did not exist

public synchronized int size()

Returns the number of key/value pairs in this Hashtable.

Returns

  • the number of key/value pairs in this Hashtable

See Also

public synchronized String toString()

Returns the string representation of this Hashtable.

Returns

  • the string representation of this Hashtable

public Collection<V> values()

Returns a Collection of the values contained in this Hashtable. The collection is backed by this Hashtable so changes to one are reflected by the other. The collection does not support adding.

Returns

  • a Collection of the values

Protected Methods

protected void rehash()

Increases the capacity of this Hashtable. This method is sent when the size of this Hashtable exceeds the load factor.
Copyright 2007 Google Inc. Build 0.9_r1-98467 - 14 Aug 2008 18:56