net.ontopia.utils
Class CompactHashMap<K,V>

java.lang.Object
  java.util.AbstractMap<K,V>
      net.ontopia.utils.CompactHashMap<K,V>

All Implemented Interfaces:

Map<K,V>

public class CompactHashMap<K,V>
extends AbstractMap<K,V>

Nested Class Summary

Nested classes/interfaces inherited from class java.util.AbstractMap

AbstractMap.SimpleEntry<K,V>, AbstractMap.SimpleImmutableEntry<K,V>

Nested classes/interfaces inherited from interface java.util.Map

Map.Entry<K,V>

Field Summary

protected static Object	deletedObject When a key is deleted this object is put into the hashtable in its place, so that other entries with the same key (collisions) further down the hashtable are not lost after we delete an object in the collision chain.
protected int	elements
protected int	freecells
protected static int	INITIAL_SIZE
protected K[]	keys
protected static double	LOAD_FACTOR
protected int	modCount
protected static Object	nullObject This object is used to represent null, should clients use that as a key.
protected V[]	values

Constructor Summary

CompactHashMap()
Constructs a new, empty set.

CompactHashMap(int size)
Constructs a new, empty set.

Method Summary

void	clear() Removes all key/value mappings in the map.
boolean	containsKey(Object k) Returns true if this map contains the specified key.
boolean	containsValue(Object v) Returns true if this map contains the specified value.
Set<Map.Entry<K,V>>	entrySet() Returns a read-only set view of the map's keys.
V	get(Object k) Returns the value for the key k, if there is one, and null if there is none.
boolean	isEmpty() Returns true if this map contains no mappings.
Set<K>	keySet() Returns a virtual read-only set of all the keys in the map.
V	put(K k, V v) Adds the specified mapping to this map, returning the old value for the mapping, if there was one.
protected void	rehash(int newCapacity) INTERNAL: Rehashes the hashmap to a bigger size.
V	remove(Object k) Removes the mapping with key k, if there is one, and returns its value, if there is one, and null if there is none.
int	size() Returns the number of key/value mappings in this map.
Collection<V>	values() Returns a virtual read-only collection containing all the values in the map.

Methods inherited from class java.util.AbstractMap

clone, equals, hashCode, putAll, toString

Methods inherited from class java.lang.Object

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

Field Detail

INITIAL_SIZE

protected static final int INITIAL_SIZE

See Also:

Constant Field Values

LOAD_FACTOR

protected static final double LOAD_FACTOR

See Also:

Constant Field Values

nullObject

protected static final Object nullObject

This object is used to represent null, should clients use that as a key.

deletedObject

protected static final Object deletedObject

When a key is deleted this object is put into the hashtable in its place, so that other entries with the same key (collisions) further down the hashtable are not lost after we delete an object in the collision chain.

elements

protected int elements

freecells

protected int freecells

keys

protected K[] keys

values

protected V[] values

modCount

protected int modCount

Constructor Detail

CompactHashMap

public CompactHashMap()

Constructs a new, empty set.

CompactHashMap

public CompactHashMap(int size)

Constructs a new, empty set.

Method Detail

size

public int size()

Returns the number of key/value mappings in this map.

Specified by:

size in interface Map<K,V>

Overrides:

size in class AbstractMap<K,V>

isEmpty

public boolean isEmpty()

Returns true if this map contains no mappings.

Specified by:

isEmpty in interface Map<K,V>

Overrides:

isEmpty in class AbstractMap<K,V>

clear

public void clear()

Removes all key/value mappings in the map.

Specified by:

clear in interface Map<K,V>

Overrides:

clear in class AbstractMap<K,V>

containsKey

public boolean containsKey(Object k)

Returns true if this map contains the specified key.

Specified by:

containsKey in interface Map<K,V>

Overrides:

containsKey in class AbstractMap<K,V>

containsValue

public boolean containsValue(Object v)

Returns true if this map contains the specified value.

Specified by:

containsValue in interface Map<K,V>

Overrides:

containsValue in class AbstractMap<K,V>

entrySet

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

Returns a read-only set view of the map's keys.

Specified by:

entrySet in interface Map<K,V>

Specified by:

entrySet in class AbstractMap<K,V>

remove

public V remove(Object k)

Removes the mapping with key k, if there is one, and returns its value, if there is one, and null if there is none.

Specified by:

remove in interface Map<K,V>

Overrides:

remove in class AbstractMap<K,V>

put

public V put(K k,
             V v)

Adds the specified mapping to this map, returning the old value for the mapping, if there was one.

Specified by:

put in interface Map<K,V>

Overrides:

put in class AbstractMap<K,V>

rehash

protected void rehash(int newCapacity)

INTERNAL: Rehashes the hashmap to a bigger size.

get

public V get(Object k)

Returns the value for the key k, if there is one, and null if there is none.

Specified by:

get in interface Map<K,V>

Overrides:

get in class AbstractMap<K,V>

values

public Collection<V> values()

Returns a virtual read-only collection containing all the values in the map.

Specified by:

values in interface Map<K,V>

Overrides:

values in class AbstractMap<K,V>

keySet

public Set<K> keySet()

Returns a virtual read-only set of all the keys in the map.

Specified by:

keySet in interface Map<K,V>

Overrides:

keySet in class AbstractMap<K,V>