Hashtable - Android SDK

Summary: Ctors | Methods | Protected Methods | Inherited Methods | [Expand All]

Added in API level 1

public class

Hashtable

extends Dictionary<K, V>
implements Map<K, V> Cloneable Serializable

java.lang.Object
↳	java.util.Dictionary<K, V>
	↳	java.util.Hashtable<K, V>

Known Direct Subclasses

Properties

Known Indirect Subclasses

AuthProvider, Provider

Class Overview

Hashtable is a synchronized implementation of Map. All optional operations are supported.

Neither keys nor values can be null. (Use HashMap or LinkedHashMap if you need null keys or values.)

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.
boolean	contains(Object value) Returns true 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 true if this `Hashtable` contains the specified object as a key of one of the key/value pairs.
synchronized boolean	containsValue(Object value) Searches this `Hashtable` for the specified value.
synchronized Enumeration<V>	elements() Returns an enumeration on the values of this `Hashtable`.
synchronized Set<Entry<K, V>>	entrySet() Returns a set of the mappings contained in this `Hashtable`.
synchronized boolean	equals(Object object) Compares this `Hashtable` with the specified object and indicates if they are equal.
synchronized V	get(Object key) Returns the value associated with the specified key in this `Hashtable`.
synchronized int	hashCode() Returns an integer hash code for this object.
synchronized boolean	isEmpty() Returns true if this `Hashtable` has no key/value pairs.
synchronized 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` instance.
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 to this `Hashtable` from the specified map.
synchronized V	remove(Object key) Removes 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`.
synchronized Collection<V>	values() Returns a collection of the values contained in this `Hashtable`.

Protected Methods
void	rehash() Increases the capacity of this `Hashtable`.

[Expand]

Inherited Methods

From class java.util.Dictionary

From class java.lang.Object

Object	clone() Creates and returns a copy of this `Object`.
boolean	equals(Object o) Compares this instance with the specified object and indicates if they are equal.
void	finalize() Invoked when the garbage collector has detected that this instance is no longer reachable.
final Class<?>	getClass() Returns the unique instance of `Class` that represents this object's class.
int	hashCode() Returns an integer hash code for this object.
final void	notify() Causes a thread which is waiting on this object's monitor (by means of calling one of the `wait()` methods) to be woken up.
final void	notifyAll() Causes all threads which are waiting on this object's monitor (by means of calling one of the `wait()` methods) to be woken up.
String	toString() Returns a string containing a concise, human-readable description of this object.
final void	wait() Causes the calling thread to wait until another thread calls the `notify()` or `notifyAll()` method of this object.
final void	wait(long millis, int nanos) Causes the calling thread to wait until another thread calls the `notify()` or `notifyAll()` method of this object or until the specified timeout expires.
final void	wait(long millis) Causes the calling thread to wait until another thread calls the `notify()` or `notifyAll()` method of this object or until the specified timeout expires.

From interface java.util.Map

abstract void	clear() Removes all elements from this `Map`, leaving it empty.
abstract boolean	containsKey(Object key) Returns whether this `Map` contains the specified key.
abstract boolean	containsValue(Object value) Returns whether this `Map` contains the specified value.
abstract Set<Entry<K, V>>	entrySet() Returns a `Set` containing all of the mappings in this `Map`.
abstract boolean	equals(Object object) Compares the argument to the receiver, and returns `true` if the specified object is a `Map` and both `Map`s contain the same mappings.
abstract V	get(Object key) Returns the value of the mapping with the specified key.
abstract int	hashCode() Returns an integer hash code for the receiver.
abstract boolean	isEmpty() Returns whether this map is empty.
abstract Set<K>	keySet() Returns a set of the keys contained in this `Map`.
abstract V	put(K key, V value) Maps the specified key to the specified value.
abstract void	putAll(Map<? extends K, ? extends V> map) Copies every mapping in the specified `Map` to this `Map`.
abstract V	remove(Object key) Removes a mapping with the specified key from this `Map`.
abstract int	size() Returns the number of mappings in this `Map`.
abstract Collection<V>	values() Returns a `Collection` of the values contained in this `Map`.

Public Constructors

public Hashtable ()

Added in API level 1

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

public Hashtable (int capacity)

Added in API level 1

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

Parameters

capacity	the initial capacity.

public Hashtable (int capacity, float loadFactor)

Added in API level 1

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)

Added in API level 1

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 ()

Added in API level 1

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

public synchronized Object clone ()

Added in API level 1

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

Returns

a shallow copy of this Hashtable.

public boolean contains (Object value)

Added in API level 1

Returns true 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)

Added in API level 1

Returns true 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 synchronized boolean containsValue (Object value)

Added in API level 1

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 ()

Added in API level 1

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 synchronized Set<Entry<K, V>> entrySet ()

Added in API level 1

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)

Added in API level 1

Compares this Hashtable with the specified object and indicates if they are equal. In order to be equal, 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.

public synchronized V get (Object key)

Added in API level 1

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, or null if the specified key does not exist.

public synchronized int hashCode ()

Added in API level 1

Returns an integer hash code for this object. By contract, any two objects for which equals(Object) returns true must return the same hash code value. This means that subclasses of Object usually override both methods or neither method.

Note that hash values must not change over time unless information used in equals comparisons also changes.

See Writing a correct hashCode method if you intend implementing your own hashCode method.

Returns

this object's hash code.

public synchronized boolean isEmpty ()

Added in API level 1

Returns true if this Hashtable has no key/value pairs.

Returns

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

public synchronized Set<K> keySet ()

Added in API level 1

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 ()

Added in API level 1

Returns an enumeration on the keys of this Hashtable instance. 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)

Added in API level 1

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, or null if the key did not exist.

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

Added in API level 1

Copies every mapping to this Hashtable from the specified map.

Parameters

map	the map to copy mappings from.

public synchronized V remove (Object key)

Added in API level 1

Removes 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, or null if the specified key did not exist.

public synchronized int size ()

Added in API level 1

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

Returns

the number of key/value pairs in this Hashtable.

public synchronized String toString ()

Added in API level 1

Returns the string representation of this Hashtable.

Returns

the string representation of this Hashtable.

public synchronized Collection<V> values ()

Added in API level 1

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 ()

Added in API level 1

Increases the capacity of this Hashtable. This method is called when the size of this Hashtable exceeds the load factor.

Results

Interfaces

Classes

Enums

Exceptions

Errors

Hashtable

Class Overview

See Also

Summary

Public Constructors

public Hashtable ()

public Hashtable (int capacity)

Parameters

public Hashtable (int capacity, float loadFactor)

Parameters

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

Parameters

Public Methods

public synchronized void clear ()

See Also

public synchronized Object clone ()

Returns

See Also

public boolean contains (Object value)

Parameters

Returns

See Also

public synchronized boolean containsKey (Object key)

Parameters

Returns

See Also

public synchronized boolean containsValue (Object value)

Parameters

Returns

public synchronized Enumeration<V> elements ()

Returns

See Also

public synchronized Set<Entry<K, V>> entrySet ()

Returns

public synchronized boolean equals (Object object)

Parameters

Returns

See Also

public synchronized V get (Object key)

Parameters

Returns

See Also

public synchronized int hashCode ()

Returns

public synchronized boolean isEmpty ()

Returns

See Also

public synchronized Set<K> keySet ()

Returns

public synchronized Enumeration<K> keys ()

Returns

See Also

public synchronized V put (K key, V value)

Parameters

Returns

See Also

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

Parameters

public synchronized V remove (Object key)

Parameters

Returns

See Also

public synchronized int size ()

Returns

See Also

public synchronized String toString ()

Returns

public synchronized Collection<V> values ()

Returns

Protected Methods

protected void rehash ()