Class HashPMap<K,V>

java.lang.Object

java.util.AbstractMap<K,V>

org.pcollections.AbstractUnmodifiableMap<K,V>

org.pcollections.HashPMap<K,V>

Type Parameters:

K -

V -

All Implemented Interfaces:

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

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

A persistent map from keys to values. Keys and values can be null.

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.

See Also:

• Serialized Form

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
(package private) static class	HashPMap.SequenceIterator<E>

Nested classes/interfaces inherited from class AbstractMap

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

Nested classes/interfaces inherited from interface Map

Map.Entry<K,V>

Field Summary

Fields

Modifier and Type	Field	Description
private Set<Map.Entry<K,V>>	entrySet	/ REQUIRED METHODS FROM AbstractMap ////
private final PMap<Integer, PSequence<Map.Entry<K,V>>>	intMap	/ PRIVATE CONSTRUCTORS ////
private static final long	serialVersionUID
private final int	size

Constructor Summary

Constructors

Modifier	Constructor	Description
private	HashPMap(PMap<Integer, PSequence<Map.Entry<K,V>>> intMap, int size)

Method Summary

Modifier and Type	Method	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)
private PSequence<Map.Entry<K,V>>	getEntries(int hash)	/ PRIVATE UTILITIES ////
private static <K,V> int	keyIndexIn(PSequence<Map.Entry<K,V>> entries, Object key)	/ PRIVATE STATIC UTILITIES ////
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)	/ IMPLEMENTED METHODS OF PMap////
int	size()	/ OVERRIDDEN METHODS FROM AbstractMap ////

Methods inherited from class AbstractUnmodifiableMap

clear, compute, computeIfAbsent, computeIfPresent, merge, put, putAll, putIfAbsent, remove, replace, replaceAll

Methods inherited from class AbstractMap

clone, containsValue, equals, hashCode, isEmpty, keySet, toString, values

Methods inherited from class Object

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

Methods inherited from interface Map

compute, computeIfAbsent, computeIfPresent, containsValue, equals, forEach, getOrDefault, hashCode, isEmpty, keySet, merge, putIfAbsent, remove, replace, replace, replaceAll, values

Methods inherited from interface PMap

clear, put, putAll, remove

Field Details

serialVersionUID

private static final long serialVersionUID

See Also:

• Constant Field Values

intMap

private final PMap<Integer, PSequence<Map.Entry<K,V>>> intMap

/ PRIVATE CONSTRUCTORS ////

size

private final int size

entrySet

private transient Set<Map.Entry<K,V>> entrySet

/ REQUIRED METHODS FROM AbstractMap ////

Constructor Details

HashPMap

private HashPMap(PMap<Integer, PSequence<Map.Entry<K,V>>> intMap,
 int size)

Method Details

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()

/ OVERRIDDEN METHODS FROM AbstractMap ////

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)

/ IMPLEMENTED METHODS OF PMap////

Specified by:

plusAll in interface PMap<K,V>

Parameters:

map -

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>

Parameters:

keys -

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 -

value -

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>

Parameters:

key -

Returns:

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

getEntries

private PSequence<Map.Entry<K,V>> getEntries(int hash)

/ PRIVATE UTILITIES ////

keyIndexIn

private static <K,V> int keyIndexIn(PSequence<Map.Entry<K,V>> entries,
 Object key)

/ PRIVATE STATIC UTILITIES ////