Hashtable< K, V > Class Reference

Inherits java::util::Dictionary< K, V >, java::util::Map< K, V >, and java::io::Serializable.

Detailed Description

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.

See also:

Enumeration

java.io.Serializable

java.lang.Object.equals

java.lang.Object.hashCode


Public Member Functions
	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.
synchronized void	clear ()
	Removes all key/value pairs from this Hashtable, leaving the size zero and the capacity unchanged.
synchronized Object	clone ()
	Answers a new Hashtable with the same key/value pairs, capacity and load factor.
synchronized boolean	contains (Object value)
	Answers if this Hashtable contains the specified object as the value of at least one of the key/value pairs.
synchronized boolean	containsKey (Object key)
	Answers 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 ()
	Answers an Enumeration on the values of this Hashtable.
Set< Map.Entry< K, V > >	entrySet ()
	Answers 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 V	get (Object key)
	Answers the value associated with the specified key in this Hashtable.
synchronized int	hashCode ()
	Answers an integer hash code for the receiver.
synchronized boolean	isEmpty ()
	Answers if this Hashtable has no key/value pairs, a size of zero.
synchronized Enumeration< K >	keys ()
	Answers an Enumeration on the keys of this Hashtable.
Set< K >	keySet ()
	Answers a Set of the keys contained in this Hashtable.
synchronized V	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 V	remove (Object key)
	Remove the key/value pair with the specified key from this Hashtable.
synchronized int	size ()
	Answers the number of key/value pairs in this Hashtable.
synchronized String	toString ()
	Answers the string representation of this Hashtable.
Collection< V >	values ()
	Answers a Collection of the values contained in this Hashtable.
Protected Member Functions
void	rehash ()
	Increases the capacity of this Hashtable.
Package Functions
Entry< K, V >	getEntry (Object key)
Package Attributes
transient int	elementCount
transient Entry< K, V >[]	elementData
transient int	firstSlot
transient int	lastSlot = -1
transient int	modCount
Private Member Functions
Entry< K, V >[]	newElementArray (int size)
void	computeMaxSize ()
synchronized void	writeObject (ObjectOutputStream stream) throws IOException
void	readObject (ObjectInputStream stream) throws IOException, ClassNotFoundException
Static Private Member Functions
static< K, V > Entry< K, V >	newEntry (K key, V value, int hash)
Private Attributes
float	loadFactor
int	threshold
Static Private Attributes
static final long	serialVersionUID = 1421746759512286392L
static final Enumeration<?>	EMPTY_ENUMERATION
Classes
class	Entry< K, V >
class	HashEnumerator< E >
class	HashIterator< E >

Constructor & Destructor Documentation

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.

Parameters:

capacity

the initial capacity

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

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

Member Function Documentation

static <K,V> Entry<K, V> newEntry	(	K	key,
		V	value,
		int	hash
	)			`[static, private]`

Entry<K, V> [] newElementArray ( int size ) [private]

synchronized void clear ( )

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

See also:: isEmpty
size

Implements Map< K, V >.

synchronized Object clone ( )

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

Returns:: a shallow copy of this Hashtable

See also:: java.lang.Cloneable

void computeMaxSize ( ) [private]

synchronized boolean contains ( Object value )

Answers 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

See also:: containsKey
java.lang.Object.equals

synchronized boolean containsKey ( Object key )

Answers 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

See also:: contains
java.lang.Object.equals

Implements Map< K, V >.

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

Implements Map< K, V >.

synchronized Enumeration<V> elements ( ) [virtual]

Answers 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

See also:

keys

size

Enumeration

Implements Dictionary< K, V >.

Set<Map.Entry<K, V> > entrySet ( )

Answers 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

Implements Map< K, V >.

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:: hashCode

Implements Map< K, V >.

synchronized V get ( Object key ) [virtual]

Answers 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:: put

Implements Dictionary< K, V >.

Entry<K, V> getEntry ( Object key ) [package]

synchronized int hashCode ( )

Answers 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:: equals

Implements Map< K, V >.

synchronized boolean isEmpty ( ) [virtual]

Answers 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:: size

Implements Dictionary< K, V >.

synchronized Enumeration<K> keys ( ) [virtual]

Answers 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

See also:

elements

size

Enumeration

Implements Dictionary< K, V >.

Set<K> keySet ( )

Answers 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

Implements Map< K, V >.

synchronized V put	(	K	key,
		V	value
	)			`[virtual]`

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

See also:

elements

get

keys

java.lang.Object.equals

Implements Dictionary< K, V >.

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

Implements Map< K, V >.

void rehash ( ) [protected]

Increases the capacity of this Hashtable.

This method is sent when the size of this Hashtable exceeds the load factor.

synchronized V remove ( Object key ) [virtual]

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

See also:: get
put

Implements Dictionary< K, V >.

synchronized int size ( ) [virtual]

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

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

See also:: elements
keys

Implements Dictionary< K, V >.

synchronized String toString ( )

Answers the string representation of this Hashtable.

Returns:: the string representation of this Hashtable

Collection<V> values ( )

Answers 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

Implements Map< K, V >.

synchronized void writeObject ( ObjectOutputStream stream ) throws IOException [private]

void readObject ( ObjectInputStream stream ) throws IOException, ClassNotFoundException [private]

Member Data Documentation

final long serialVersionUID = 1421746759512286392L [static, private]

transient int elementCount [package]

transient Entry<K, V> [] elementData [package]

float loadFactor [private]

int threshold [private]

transient int firstSlot [package]

transient int lastSlot = -1 [package]

transient int modCount [package]

final Enumeration<?> EMPTY_ENUMERATION [static, private]

Initial value:

 new Enumeration<Object>() {
        public boolean hasMoreElements() {
            return false;
        }

        public Object nextElement() {
            throw new NoSuchElementException();
        }
    }

Ja.NET Standard Edition 5.0

Documentation API Specification

Hashtable< K, V > Class Reference

Detailed Description

Public Member Functions

Protected Member Functions

Package Functions

Package Attributes

Private Member Functions

Static Private Member Functions

Private Attributes

Static Private Attributes

Classes

Constructor & Destructor Documentation

Member Function Documentation

Member Data Documentation