org.pcollections

Class HashPMap<K,V>

java.lang.Object

java.util.AbstractMap<K,V>

org.pcollections.HashPMap<K,V>

Type Parameters:

K -

V -

All Implemented Interfaces:

Map<K,V>, PMap<K,V>

public final class HashPMap<K,V>
extends AbstractMap<K,V>
implements PMap<K,V>

A persistent map from non-null keys to non-null values.

This map uses a given integer map to map hashcodes to lists of elements with the same hashcode. Thus if all elements have the same hashcode, performance is reduced to that of an association list.

This implementation is thread-safe (assuming Java's AbstractMap and AbstractSet are thread-safe), although its iterators may not be.

Author:

harold

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>

Method Summary

Methods

Modifier and Type	Method and Description
boolean	containsKey(Object key)
static <K,V> HashPMap<K,V>	empty(PMap<Integer,PSequence<Map.Entry<K,V>>> intMap)
Set<Map.Entry<K,V>>	entrySet()
V	get(Object key)
HashPMap<K,V>	minus(Object key)
HashPMap<K,V>	minusAll(Collection<?> keys)
HashPMap<K,V>	plus(K key, V value)
HashPMap<K,V>	plusAll(Map<? extends K,? extends V> map)
int	size()

Methods inherited from class java.util.AbstractMap

clear, clone, containsValue, equals, hashCode, isEmpty, keySet, put, putAll, remove, toString, values

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.pcollections.PMap

clear, put, putAll, remove

Methods inherited from interface java.util.Map

containsValue, equals, hashCode, isEmpty, keySet, values

Method Detail

empty

public static <K,V> HashPMap<K,V> empty(PMap<Integer,PSequence<Map.Entry<K,V>>> intMap)

Type Parameters:

K -

V -

Parameters:

intMap -

Returns:

a map backed by an empty version of intMap, i.e. backed by intMap.minusAll(intMap.keySet())

entrySet

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

Specified by:

entrySet in interface Map<K,V>

Specified by:

entrySet in class AbstractMap<K,V>

size

public int size()

Specified by:

size in interface Map<K,V>

Overrides:

size in class AbstractMap<K,V>

containsKey

public boolean containsKey(Object key)

Specified by:

containsKey in interface Map<K,V>

Overrides:

containsKey in class AbstractMap<K,V>

get

public V get(Object key)

Specified by:

get in interface Map<K,V>

Overrides:

get in class AbstractMap<K,V>

plusAll

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

Specified by:

plusAll in interface PMap<K,V>

Returns:

this combined with map, with map's mappings used for any keys in both map and this

minusAll

public HashPMap<K,V> minusAll(Collection<?> keys)

Specified by:

minusAll in interface PMap<K,V>

Returns:

a map with the mappings of this but with no value for any element of keys

plus

public HashPMap<K,V> plus(K key,
                 V value)

Specified by:

plus in interface PMap<K,V>

Parameters:

key - non-null

value - non-null

Returns:

a map with the mappings of this but with key mapped to value

minus

public HashPMap<K,V> minus(Object key)

Specified by:

minus in interface PMap<K,V>

Returns:

a map with the mappings of this but with no value for key