org.apache.pivot.collections
Class HashMap<K,V>

java.lang.Object
  org.apache.pivot.collections.HashMap<K,V>

All Implemented Interfaces:

Serializable, Iterable<K>, Collection<K>, Dictionary<K,V>, Map<K,V>

public class HashMap<K,V>
extends Object
implements Map<K,V>, Serializable

Implementation of the Map interface that is backed by a hash table.

See Also:

Serialized Form

Nested Class Summary

Nested classes/interfaces inherited from interface org.apache.pivot.collections.Map

Map.MapListenerList<K,V>

Nested classes/interfaces inherited from interface org.apache.pivot.collections.Dictionary

Dictionary.Pair<K,V>

Field Summary

static int	DEFAULT_CAPACITY
static float	DEFAULT_LOAD_FACTOR

Constructor Summary

HashMap()

HashMap(Comparator<K> comparator)

HashMap(Dictionary.Pair<K,V>... entries)

HashMap(int capacity)

HashMap(int capacity, float loadFactor)

HashMap(Map<K,V> map)

Method Summary

void	clear() Removes all entries in the map.
boolean	containsKey(K key) Tests the existence of a key in the dictionary.
boolean	equals(Object o)
V	get(K key) Retrieves the value for the given key.
int	getCapacity()
Comparator<K>	getComparator() Returns the collection's sort order.
int	getCount() Returns the number of entries in the map.
ListenerList<MapListener<K,V>>	getMapListeners() Returns the map listener collection.
int	hashCode()
boolean	isEmpty() Tests the emptiness of the collection.
Iterator<K>	iterator()
V	put(K key, V value) Sets the value of the given key, creating a new entry or replacing the existing value, and firing a corresponding event.
V	remove(K key) Removes a key/value pair from the map.
void	setComparator(Comparator<K> comparator) Sets the collection's sort order, re-ordering the collection's contents and ensuring that new entries preserve the sort order.
String	toString()

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Field Detail

DEFAULT_CAPACITY

public static final int DEFAULT_CAPACITY

See Also:

Constant Field Values

DEFAULT_LOAD_FACTOR

public static final float DEFAULT_LOAD_FACTOR

See Also:

Constant Field Values

Constructor Detail

HashMap

public HashMap()

HashMap

public HashMap(int capacity)

HashMap

public HashMap(int capacity,
               float loadFactor)

HashMap

public HashMap(Dictionary.Pair<K,V>... entries)

HashMap

public HashMap(Map<K,V> map)

HashMap

public HashMap(Comparator<K> comparator)

Method Detail

get

public V get(K key)

Retrieves the value for the given key.

Specified by:

get in interface Dictionary<K,V>

Parameters:

key - The key whose value is to be returned.

Returns:

The value corresponding to key, or null if the key does not exist. Will also return null if the key refers to a null value. Use containsKey() to distinguish between these two cases.

Throws:

IllegalArgumentException - If key is null.

put

public V put(K key,
             V value)

Sets the value of the given key, creating a new entry or replacing the existing value, and firing a corresponding event.

Specified by:

put in interface Dictionary<K,V>

Specified by:

put in interface Map<K,V>

Parameters:

key - The key whose value is to be set.

value - The value to be associated with the given key.

Returns:

The value previously associated with the key.

Throws:

IllegalArgumentException - If key is null.

See Also:

MapListener.valueAdded(Map, Object), MapListener.valueUpdated(Map, Object, Object)

remove

public V remove(K key)

Removes a key/value pair from the map.

Specified by:

remove in interface Dictionary<K,V>

Specified by:

remove in interface Map<K,V>

Parameters:

key - The key whose mapping is to be removed.

Returns:

The value that was removed.

Throws:

IllegalArgumentException - If key is null.

See Also:

MapListener.valueRemoved(Map, Object, Object)

clear

public void clear()

Description copied from interface: Map

Removes all entries in the map.

Specified by:

clear in interface Collection<K>

Specified by:

clear in interface Map<K,V>

See Also:

MapListener.mapCleared(Map)

containsKey

public boolean containsKey(K key)

Tests the existence of a key in the dictionary.

Specified by:

containsKey in interface Dictionary<K,V>

Parameters:

key - The key whose presence in the dictionary is to be tested.

Returns:

true if the key exists in the dictionary; false, otherwise.

Throws:

IllegalArgumentException - If key is null.

isEmpty

public boolean isEmpty()

Description copied from interface: Collection

Tests the emptiness of the collection.

Specified by:

isEmpty in interface Collection<K>

Returns:

true if the collection contains no elements; false, otherwise.

getCount

public int getCount()

Description copied from interface: Map

Returns the number of entries in the map.

Specified by:

getCount in interface Map<K,V>

getCapacity

public int getCapacity()

getComparator

public Comparator<K> getComparator()

Description copied from interface: Collection

Returns the collection's sort order.

Specified by:

getComparator in interface Collection<K>

Returns:

The comparator used to order elements in the collection, or null if the sort order is undefined.

See Also:

Collection.setComparator(Comparator)

setComparator

public void setComparator(Comparator<K> comparator)

Description copied from interface: Collection

Sets the collection's sort order, re-ordering the collection's contents and ensuring that new entries preserve the sort order.

Calling this method more than once with the same comparator will re-sort the collection.

Specified by:

setComparator in interface Collection<K>

Specified by:

setComparator in interface Map<K,V>

Parameters:

comparator - The comparator used to order elements in the collection, or null if the collection is unsorted.

See Also:

MapListener.comparatorChanged(Map, Comparator)

iterator

public Iterator<K> iterator()

Specified by:

iterator in interface Iterable<K>

getMapListeners

public ListenerList<MapListener<K,V>> getMapListeners()

Description copied from interface: Map

Returns the map listener collection.

Specified by:

getMapListeners in interface Map<K,V>

equals

public boolean equals(Object o)

Overrides:

equals in class Object

hashCode

public int hashCode()

Overrides:

hashCode in class Object

toString

public String toString()

Overrides:

toString in class Object