org.organicdesign.fp.collections

Class PersistentHashMap<K,V>

java.lang.Object

org.organicdesign.fp.collections.UnmodIterable.AbstractUnmodIterable<UnmodMap.UnEntry<K,V>>

org.organicdesign.fp.collections.UnmodMap.AbstractUnmodMap<K,V>

org.organicdesign.fp.collections.PersistentHashMap<K,V>

All Implemented Interfaces:

Serializable, Iterable<UnmodMap.UnEntry<K,V>>, Map<K,V>, ImMap<K,V>, ImUnsortedMap<K,V>, Sized, UnmodIterable<UnmodMap.UnEntry<K,V>>, UnmodMap<K,V>, Transformable<UnmodMap.UnEntry<K,V>>

public class PersistentHashMap<K,V>
extends UnmodMap.AbstractUnmodMap<K,V>
implements ImUnsortedMap<K,V>, Serializable

Rich Hickey's immutable rendition of Phil Bagwell's Hash Array Mapped Trie. Uses path copying for persistence, HashCollision leaves vs. extended hashing, Node polymorphism vs. conditionals, No sub-tree pools or root-resizing. Any errors are my own (said Rich, but now says Glen 2015-06-06). This file is a derivative work based on a Clojure collection licensed under the Eclipse Public License 1.0 Copyright Rich Hickey. Errors are Glen Peterson's.

See Also:

Serialized Form

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	PersistentHashMap.MutableHashMap<K,V>

Nested classes/interfaces inherited from interface org.organicdesign.fp.collections.UnmodMap

UnmodMap.AbstractUnmodMap<K,V>, UnmodMap.UnEntry<K,V>

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

Map.Entry<K,V>

Nested classes/interfaces inherited from interface org.organicdesign.fp.collections.UnmodIterable

UnmodIterable.AbstractUnmodIterable<T>

Field Summary

Fields

Modifier and Type	Field and Description
static PersistentHashMap<Object,Object>	EMPTY

Method Summary

Modifier and Type	Method and Description
PersistentHashMap<K,V>	assoc(K key, V val) Returns a new map with the given key/value added
static <K,V> PersistentHashMap<K,V>	empty()
static <K,V> PersistentHashMap<K,V>	empty(Equator<K> e)
static <K,V> PersistentHashMap.MutableHashMap<K,V>	emptyMutable() Works around some type inference limitations of Java 8.
static <K,V> PersistentHashMap.MutableHashMap<K,V>	emptyMutable(Equator<K> e) Works around some type inference limitations of Java 8.
Option<UnmodMap.UnEntry<K,V>>	entry(K key)
Equator<K>	equator() Returns the Equator used by this map for equals comparisons and hashCodes
PersistentHashMap<K,V>	immutable() Returns a immutable version of this (maybe) mutable map.
UnmodIterator<UnmodMap.UnEntry<K,V>>	iterator() A one-time use, mutable, not-thread-safe way to get each value of the underling collection in turn.
PersistentHashMap.MutableHashMap<K,V>	mutable() Returns a mutable version of this immutable map.
static <K,V> PersistentHashMap<K,V>	of(Iterable<Map.Entry<K,V>> kvPairs) Returns a new PersistentHashMap of the given keys and their paired values.
static <K,V> PersistentHashMap<K,V>	ofEq(Equator<K> eq, Iterable<Map.Entry<K,V>> es) Returns a new PersistentHashMap of the given keys and their paired values, skipping any null Entries.
int	size() Returns the number of items in this iterable.
PersistentHashMap<K,V>	without(K key) Returns a new map with the given key/value removed

Methods inherited from class org.organicdesign.fp.collections.UnmodMap.AbstractUnmodMap

equals

Methods inherited from class org.organicdesign.fp.collections.UnmodIterable.AbstractUnmodIterable

hashCode, toString

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.organicdesign.fp.collections.ImUnsortedMap

assoc, keySet

Methods inherited from interface org.organicdesign.fp.collections.ImMap

containsKey, entrySet, get, getOrElse

Methods inherited from interface org.organicdesign.fp.collections.UnmodMap

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

Methods inherited from interface java.util.Map

equals, forEach, getOrDefault, hashCode

Methods inherited from interface org.organicdesign.fp.collections.UnmodIterable

concat, drop, filter, flatMap, foldLeft, foldLeft, hash, hashCode, head, map, precat, take, takeWhile, toString

Methods inherited from interface java.lang.Iterable

forEach, spliterator

Methods inherited from interface org.organicdesign.fp.xform.Transformable

toImList, toImMap, toImSet, toImSortedMap, toImSortedSet, toMutableList, toMutableMap, toMutableSet, toMutableSortedMap, toMutableSortedSet

Field Detail

EMPTY

public static final PersistentHashMap<Object,Object> EMPTY

Method Detail

empty

public static <K,V> PersistentHashMap<K,V> empty()

emptyMutable

public static <K,V> PersistentHashMap.MutableHashMap<K,V> emptyMutable()

Works around some type inference limitations of Java 8.

empty

public static <K,V> PersistentHashMap<K,V> empty(Equator<K> e)

emptyMutable

public static <K,V> PersistentHashMap.MutableHashMap<K,V> emptyMutable(Equator<K> e)

Works around some type inference limitations of Java 8.

ofEq

public static <K,V> PersistentHashMap<K,V> ofEq(Equator<K> eq,
                                                Iterable<Map.Entry<K,V>> es)

Returns a new PersistentHashMap of the given keys and their paired values, skipping any null Entries.

of

public static <K,V> PersistentHashMap<K,V> of(Iterable<Map.Entry<K,V>> kvPairs)

Returns a new PersistentHashMap of the given keys and their paired values. There is also a varargs version of this method: StaticImports.map(Map.Entry...). Use the StaticImports.tup(Object, Object) method to define key/value pairs briefly and easily.

Parameters:

kvPairs - Key/value pairs (to go into the map). In the case of a duplicate key, later values in the input list overwrite the earlier ones. The resulting map can contain zero or one null key and any number of null values. Null k/v pairs will be silently ignored.

Returns:

a new PersistentHashMap of the given key/value pairs

equator

public Equator<K> equator()

Returns the Equator used by this map for equals comparisons and hashCodes

Specified by:

equator in interface ImUnsortedMap<K,V>

assoc

public PersistentHashMap<K,V> assoc(K key,
                                    V val)

Description copied from interface: ImUnsortedMap

Returns a new map with the given key/value added

Specified by:

assoc in interface ImMap<K,V>

Specified by:

assoc in interface ImUnsortedMap<K,V>

mutable

public PersistentHashMap.MutableHashMap<K,V> mutable()

Description copied from interface: ImUnsortedMap

Returns a mutable version of this immutable map.

Specified by:

mutable in interface ImUnsortedMap<K,V>

entry

public Option<UnmodMap.UnEntry<K,V>> entry(K key)

Specified by:

entry in interface ImMap<K,V>

iterator

public UnmodIterator<UnmodMap.UnEntry<K,V>> iterator()

Description copied from interface: UnmodIterable

A one-time use, mutable, not-thread-safe way to get each value of the underling collection in turn. I experimented with various thread-safe alternatives, but the JVM is optimized around iterators so this is the lowest common denominator of collection iteration, even though iterators are inherently mutable.

Specified by:

iterator in interface Iterable<UnmodMap.UnEntry<K,V>>

Specified by:

iterator in interface UnmodIterable<UnmodMap.UnEntry<K,V>>

immutable

public final PersistentHashMap<K,V> immutable()

Description copied from interface: ImUnsortedMap

Returns a immutable version of this (maybe) mutable map. Maybe this should be on ImUnsortedMapTrans only, but that prevents reusing a variable to hold both a mutable and immutable map. I really wasn't sure of the right thing to do here. Sometimes you want a guaranteed mutable. Sometimes a guaranteed immutable. I suppose you can use the specific implementation class in that case. Inheritance forces you to pick one.

Specified by:

immutable in interface ImUnsortedMap<K,V>

size

public int size()

Returns the number of items in this iterable.

Specified by:

size in interface Map<K,V>

Specified by:

size in interface Sized

without

public PersistentHashMap<K,V> without(K key)

Description copied from interface: ImUnsortedMap

Returns a new map with the given key/value removed

Specified by:

without in interface ImMap<K,V>

Specified by:

without in interface ImUnsortedMap<K,V>