HashMap (vavr-champ 0.10.5 API)

java.lang.Object
- io.vavr.collection.HashMap<K,V>

Type Parameters:

K - the key type

V - the value type

All Implemented Interfaces:

Foldable<Tuple2<K,V>>, Map<K,V>, Traversable<Tuple2<K,V>>, Function1<K,V>, PartialFunction<K,V>, Value<Tuple2<K,V>>, java.io.Serializable, java.lang.Iterable<Tuple2<K,V>>, java.util.function.Function<K,V>
```
public final class HashMap<K,V>
extends java.lang.Object
implements Map<K,V>, java.io.Serializable
```
Implements an immutable map using a Compressed Hash-Array Mapped Prefix-tree (CHAMP).
Features:
- supports up to 2³⁰ entries
- allows null keys and null values
- is immutable
- is thread-safe
- does not guarantee a specific iteration order
Performance characteristics:
- put: O(1)
- remove: O(1)
- containsKey: O(1)
- toMutable: O(1) + O(log N) distributed across subsequent updates in the mutable copy
- clone: O(1)
- iterator.next(): O(1)
Implementation details:
This map performs read and write operations of single elements in O(1) time, and in O(1) space.
The CHAMP trie contains nodes that may be shared with other maps.
If a write operation is performed on a node, then this map creates a copy of the node and of all parent nodes up to the root (copy-path-on-write). Since the CHAMP trie has a fixed maximal height, the cost is O(1).
All operations on this map can be performed concurrently, without a need for synchronisation.
The immutable version of this map extends from the non-public class ChampBitmapIndexNode. This design safes 16 bytes for every instance, and reduces the number of redirections for finding an element in the collection by 1.
References:
Portions of the code in this class have been derived from 'The Capsule Hash Trie Collections Library', and from 'JHotDraw 8'.

Michael J. Steindorfer (2017). Efficient Immutable Collections.

michael.steindorfer.name

The Capsule Hash Trie Collections Library.
Copyright (c) Michael Steindorfer. BSD-2-Clause License

github.com

JHotDraw 8. Copyright © 2023 The authors and contributors of JHotDraw. MIT License.

github.com
See Also:

Serialized Form

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`<K2,V2> HashMap<K2,V2>`	`bimap(java.util.function.Function<? super K,? extends K2> keyMapper, java.util.function.Function<? super V,? extends V2> valueMapper)` Maps this `Map` to a new `Map` with different component type by applying a function to its elements.
`static <K,V> java.util.stream.Collector<Tuple2<K,V>,java.util.ArrayList<Tuple2<K,V>>,HashMap<K,V>>`	`collector()` Returns a `Collector` which may be used in conjunction with `Stream.collect(java.util.stream.Collector)` to obtain a `HashMap`.
`static <K,V,T extends V> java.util.stream.Collector<T,java.util.ArrayList<T>,HashMap<K,V>>`	`collector(java.util.function.Function<? super T,? extends K> keyMapper)` Returns a `Collector` which may be used in conjunction with `Stream.collect(java.util.stream.Collector)` to obtain a `HashMap`.
`static <K,V,T> java.util.stream.Collector<T,java.util.ArrayList<T>,HashMap<K,V>>`	`collector(java.util.function.Function<? super T,? extends K> keyMapper, java.util.function.Function<? super T,? extends V> valueMapper)` Returns a `Collector` which may be used in conjunction with `Stream.collect(java.util.stream.Collector)` to obtain a `HashMap`.
`Tuple2<V,HashMap<K,V>>`	`computeIfAbsent(K key, java.util.function.Function<? super K,? extends V> mappingFunction)` If the specified key is not already associated with a value, attempts to compute its value using the given mapping function and enters it into this map.
`Tuple2<Option<V>,HashMap<K,V>>`	`computeIfPresent(K key, java.util.function.BiFunction<? super K,? super V,? extends V> remappingFunction)` If the value for the specified key is present, attempts to compute a new mapping given the key and its current mapped value.
`boolean`	`containsKey(K key)` Returns `true` if this map contains a mapping for the specified key.
`HashMap<K,V>`	`distinct()` Returns a new version of this which contains no duplicates.
`HashMap<K,V>`	`distinctBy(java.util.Comparator<? super Tuple2<K,V>> comparator)` Returns a new version of this which contains no duplicates.
`<U> HashMap<K,V>`	`distinctBy(java.util.function.Function<? super Tuple2<K,V>,? extends U> keyExtractor)` Returns a new version of this which contains no duplicates.
`HashMap<K,V>`	`drop(int n)` Drops the first n elements of this or all elements, if this length < n.
`HashMap<K,V>`	`dropRight(int n)` Drops the last n elements of this or all elements, if this length < n.
`HashMap<K,V>`	`dropUntil(java.util.function.Predicate<? super Tuple2<K,V>> predicate)` Drops elements until the predicate holds for the current element.
`HashMap<K,V>`	`dropWhile(java.util.function.Predicate<? super Tuple2<K,V>> predicate)` Drops elements while the predicate holds for the current element.
`static <K,V> HashMap<K,V>`	`empty()`
`boolean`	`equals(java.lang.Object other)` In Vavr there are four basic classes of collections: Seq (sequential elements) Set (distinct elements) Map (indexed elements) Multimap (indexed collections) Two collection instances of these classes are equal if and only if both collections belong to the same basic collection class (Seq, Set, Map or Multimap) contain the same elements have the same element order, if the collections are of type Seq Two Map/Multimap elements, resp.
`static <K,V> HashMap<K,V>`	`fill(int n, java.util.function.Supplier<? extends Tuple2<? extends K,? extends V>> s)` Returns a HashMap containing tuples returned by `n` calls to a given Supplier `s`.
`HashMap<K,V>`	`filter(java.util.function.BiPredicate<? super K,? super V> predicate)` Returns a new Map consisting of all elements which satisfy the given predicate.
`HashMap<K,V>`	`filter(java.util.function.Predicate<? super Tuple2<K,V>> predicate)` Returns a new traversable consisting of all elements which satisfy the given predicate.
`HashMap<K,V>`	`filterKeys(java.util.function.Predicate<? super K> predicate)` Returns a new Map consisting of all elements with keys which satisfy the given predicate.
`HashMap<K,V>`	`filterNot(java.util.function.BiPredicate<? super K,? super V> predicate)` Returns a new Map consisting of all elements which do not satisfy the given predicate.
`HashMap<K,V>`	`filterNot(java.util.function.Predicate<? super Tuple2<K,V>> predicate)` Returns a new traversable consisting of all elements which do not satisfy the given predicate.
`HashMap<K,V>`	`filterNotKeys(java.util.function.Predicate<? super K> predicate)` Returns a new Map consisting of all elements with keys which do not satisfy the given predicate.
`HashMap<K,V>`	`filterNotValues(java.util.function.Predicate<? super V> predicate)` Returns a new Map consisting of all elements with values which do not satisfy the given predicate.
`HashMap<K,V>`	`filterValues(java.util.function.Predicate<? super V> predicate)` Returns a new Map consisting of all elements with values which satisfy the given predicate.
`<K2,V2> HashMap<K2,V2>`	`flatMap(java.util.function.BiFunction<? super K,? super V,? extends java.lang.Iterable<Tuple2<K2,V2>>> mapper)` FlatMaps this `Map` to a new `Map` with different component type.
`Option<V>`	`get(K key)` Returns the `Some` of value to which the specified key is mapped, or `None` if this map contains no mapping for the key.
`V`	`getOrElse(K key, V defaultValue)` Returns the value associated with a key, or a default value if the key is not contained in the map.
`<C> Map<C,HashMap<K,V>>`	`groupBy(java.util.function.Function<? super Tuple2<K,V>,? extends C> classifier)` Groups this elements by classifying the elements.
`Iterator<HashMap<K,V>>`	`grouped(int size)` Groups this `Traversable` into fixed size blocks.
`int`	`hashCode()` Returns the hash code of this collection.
`Tuple2<K,V>`	`head()` Returns the first element of a non-empty Traversable.
`HashMap<K,V>`	`init()` XXX We return tail() here.
`Option<HashMap<K,V>>`	`initOption()` Dual of Traversable.tailOption(), returning all elements except the last as `Option`.
`boolean`	`isAsync()` A `HashMap` is computed synchronously.
`boolean`	`isEmpty()` Checks if this Traversable is empty.
`boolean`	`isLazy()` A `HashMap` is computed eagerly.
`Iterator<Tuple2<K,V>>`	`iterator()` An iterator by means of head() and tail().
`Set<K>`	`keySet()` Returns the keys contained in this map.
`Iterator<K>`	`keysIterator()` Returns the keys contained in this map as an iterator.
`Tuple2<K,V>`	`last()` Dual of Traversable.head(), returning the last element.
`<K2,V2> HashMap<K2,V2>`	`map(java.util.function.BiFunction<? super K,? super V,Tuple2<K2,V2>> mapper)` Maps the entries of this `Map` to form a new `Map`.
`<K2> HashMap<K2,V>`	`mapKeys(java.util.function.Function<? super K,? extends K2> keyMapper)` Maps the keys of this `Map` while preserving the corresponding values.
`<K2> HashMap<K2,V>`	`mapKeys(java.util.function.Function<? super K,? extends K2> keyMapper, java.util.function.BiFunction<? super V,? super V,? extends V> valueMerge)` Maps the keys of this `Map` while preserving the corresponding values and applying a value merge function on collisions.
`<V2> HashMap<K,V2>`	`mapValues(java.util.function.Function<? super V,? extends V2> valueMapper)` Maps the values of this `Map` while preserving the corresponding keys.
`HashMap<K,V>`	`merge(Map<? extends K,? extends V> that)` Creates a new map which by merging the entries of `this` map and `that` map.
`<U extends V> HashMap<K,V>`	`merge(Map<? extends K,U> that, java.util.function.BiFunction<? super V,? super U,? extends V> collisionResolution)` Creates a new map which by merging the entries of `this` map and `that` map.
`static <K,V> HashMap<K,V>`	`narrow(HashMap<? extends K,? extends V> hashMap)` Narrows a widened `HashMap<? extends K, ? extends V>` to `HashMap<K, V>` by performing a type-safe cast.
`static <K,V> HashMap<K,V>`	`of(K key, V value)` Returns a singleton `HashMap`, i.e.
`static <K,V> HashMap<K,V>`	`of(K k1, V v1, K k2, V v2)` Creates a HashMap of the given list of key-value pairs.
`static <K,V> HashMap<K,V>`	`of(K k1, V v1, K k2, V v2, K k3, V v3)` Creates a HashMap of the given list of key-value pairs.
`static <K,V> HashMap<K,V>`	`of(K k1, V v1, K k2, V v2, K k3, V v3, K k4, V v4)` Creates a HashMap of the given list of key-value pairs.
`static <K,V> HashMap<K,V>`	`of(K k1, V v1, K k2, V v2, K k3, V v3, K k4, V v4, K k5, V v5)` Creates a HashMap of the given list of key-value pairs.
`static <K,V> HashMap<K,V>`	`of(K k1, V v1, K k2, V v2, K k3, V v3, K k4, V v4, K k5, V v5, K k6, V v6)` Creates a HashMap of the given list of key-value pairs.
`static <K,V> HashMap<K,V>`	`of(K k1, V v1, K k2, V v2, K k3, V v3, K k4, V v4, K k5, V v5, K k6, V v6, K k7, V v7)` Creates a HashMap of the given list of key-value pairs.
`static <K,V> HashMap<K,V>`	`of(K k1, V v1, K k2, V v2, K k3, V v3, K k4, V v4, K k5, V v5, K k6, V v6, K k7, V v7, K k8, V v8)` Creates a HashMap of the given list of key-value pairs.
`static <K,V> HashMap<K,V>`	`of(K k1, V v1, K k2, V v2, K k3, V v3, K k4, V v4, K k5, V v5, K k6, V v6, K k7, V v7, K k8, V v8, K k9, V v9)` Creates a HashMap of the given list of key-value pairs.
`static <K,V> HashMap<K,V>`	`of(K k1, V v1, K k2, V v2, K k3, V v3, K k4, V v4, K k5, V v5, K k6, V v6, K k7, V v7, K k8, V v8, K k9, V v9, K k10, V v10)` Creates a HashMap of the given list of key-value pairs.
`static <K,V> HashMap<K,V>`	`of(Tuple2<? extends K,? extends V> entry)` Returns a singleton `HashMap`, i.e.
`static <K,V> HashMap<K,V>`	`ofAll(java.util.Map<? extends K,? extends V> map)` Returns a `HashMap`, from a source java.util.Map.
`static <T,K,V> HashMap<K,V>`	`ofAll(java.util.stream.Stream<? extends T> stream, java.util.function.Function<? super T,? extends K> keyMapper, java.util.function.Function<? super T,? extends V> valueMapper)` Returns a `HashMap`, from entries mapped from stream.
`static <T,K,V> HashMap<K,V>`	`ofAll(java.util.stream.Stream<? extends T> stream, java.util.function.Function<? super T,Tuple2<? extends K,? extends V>> entryMapper)` Returns a `HashMap`, from entries mapped from stream.
`static <K,V> HashMap<K,V>`	`ofEntries(java.lang.Iterable<? extends Tuple2<? extends K,? extends V>> entries)` Creates a HashMap of the given entries.
`static <K,V> HashMap<K,V>`	`ofEntries(java.util.Map.Entry<? extends K,? extends V>... entries)` Creates a HashMap of the given entries.
`static <K,V> HashMap<K,V>`	`ofEntries(Tuple2<? extends K,? extends V>... entries)` Creates a HashMap of the given entries.
`HashMap<K,V>`	`orElse(java.lang.Iterable<? extends Tuple2<K,V>> other)` Returns this `Traversable` if it is nonempty, otherwise return the alternative.
`HashMap<K,V>`	`orElse(java.util.function.Supplier<? extends java.lang.Iterable<? extends Tuple2<K,V>>> supplier)` Returns this `Traversable` if it is nonempty, otherwise return the result of evaluating supplier.
`Tuple2<HashMap<K,V>,HashMap<K,V>>`	`partition(java.util.function.Predicate<? super Tuple2<K,V>> predicate)` Creates a partition of this `Traversable` by splitting this elements in two in distinct traversables according to a predicate.
`HashMap<K,V>`	`peek(java.util.function.Consumer<? super Tuple2<K,V>> action)` Performs the given `action` on the first element if this is an eager implementation.
`<U extends V> HashMap<K,V>`	`put(K key, U value, java.util.function.BiFunction<? super V,? super U,? extends V> merge)` Associates the specified value with the specified key in this map.
`HashMap<K,V>`	`put(K key, V value)` Associates the specified value with the specified key in this map.
`HashMap<K,V>`	`put(Tuple2<? extends K,? extends V> entry)` Convenience method for `put(entry._1, entry._2)`.
`<U extends V> HashMap<K,V>`	`put(Tuple2<? extends K,U> entry, java.util.function.BiFunction<? super V,? super U,? extends V> merge)` Convenience method for `put(entry._1, entry._2, merge)`.
`HashMap<K,V>`	`remove(K key)` Removes the mapping for a key from this map if it is present.
`HashMap<K,V>`	`removeAll(java.lang.Iterable<? extends K> c)` Removes the mapping for a key from this map if it is present.
`HashMap<K,V>`	`replace(K key, V oldValue, V newValue)` Replaces the entry for the specified key only if currently mapped to the specified value.
`HashMap<K,V>`	`replace(Tuple2<K,V> currentElement, Tuple2<K,V> newElement)` Replaces the first occurrence (if exists) of the given currentElement with newElement.
`HashMap<K,V>`	`replaceAll(java.util.function.BiFunction<? super K,? super V,? extends V> function)` Replaces each entry's value with the result of invoking the given function on that entry until all entries have been processed or the function throws an exception.
`HashMap<K,V>`	`replaceAll(Tuple2<K,V> currentElement, Tuple2<K,V> newElement)` Replaces all occurrences of the given currentElement with newElement.
`HashMap<K,V>`	`replaceValue(K key, V value)` Replaces the entry for the specified key only if it is currently mapped to some value.
`HashMap<K,V>`	`retainAll(java.lang.Iterable<? extends Tuple2<K,V>> elements)` Keeps all occurrences of the given elements from this.
`HashMap<K,V>`	`scan(Tuple2<K,V> zero, java.util.function.BiFunction<? super Tuple2<K,V>,? super Tuple2<K,V>,? extends Tuple2<K,V>> operation)` Computes a prefix scan of the elements of the collection.
`int`	`size()` Computes the number of elements of this Traversable.
`Iterator<HashMap<K,V>>`	`slideBy(java.util.function.Function<? super Tuple2<K,V>,?> classifier)` Slides a non-overlapping window of a variable size over this `Traversable`.
`Iterator<HashMap<K,V>>`	`sliding(int size)` Slides a window of a specific `size` and step size 1 over this `Traversable` by calling `Traversable.sliding(int, int)`.
`Iterator<HashMap<K,V>>`	`sliding(int size, int step)` Slides a window of a specific `size` and `step` size over this `Traversable`.
`Tuple2<HashMap<K,V>,HashMap<K,V>>`	`span(java.util.function.Predicate<? super Tuple2<K,V>> predicate)` Returns a tuple where the first element is the longest prefix of elements that satisfy the given `predicate` and the second element is the remainder.
`java.util.Spliterator<Tuple2<K,V>>`	`spliterator()`
`java.lang.String`	`stringPrefix()` Returns the name of this Value type, which is used by toString().
`static <K,V> HashMap<K,V>`	`tabulate(int n, java.util.function.Function<? super java.lang.Integer,? extends Tuple2<? extends K,? extends V>> f)` Returns an HashMap containing `n` values of a given Function `f` over a range of integer values from 0 to `n - 1`.
`HashMap<K,V>`	`tail()` Drops the first element of a non-empty Traversable.
`Option<HashMap<K,V>>`	`tailOption()` Drops the first element of a non-empty Traversable and returns an `Option`.
`HashMap<K,V>`	`take(int n)` Takes the first n elements of this or all elements, if this length < n.
`HashMap<K,V>`	`takeRight(int n)` Takes the last n elements of this or all elements, if this length < n.
`HashMap<K,V>`	`takeUntil(java.util.function.Predicate<? super Tuple2<K,V>> predicate)` Takes elements until the predicate holds for the current element.
`HashMap<K,V>`	`takeWhile(java.util.function.Predicate<? super Tuple2<K,V>> predicate)` Takes elements while the predicate holds for the current element.
`java.util.HashMap<K,V>`	`toJavaMap()` Converts this Vavr `Map` to a `java.util.Map` while preserving characteristics like insertion order (`LinkedHashMap`) and sort order (`SortedMap`).
`java.lang.String`	`toString()` Clarifies that values have a proper toString() method implemented.
`Stream<V>`	`values()` Returns a new `Seq` that contains the values of this `Map`.
`Iterator<V>`	`valuesIterator()` Returns the values in this map.

Methods inherited from class java.lang.Object
clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Methods inherited from interface io.vavr.collection.Map
apply, asPartialFunction, collect, contains, containsValue, entry, flatMap, foldRight, forEach, hasDefiniteSize, isDefinedAt, isDistinct, isTraversableAgain, iterator, length, lift, map, narrow, scanLeft, scanRight, transform, unzip, zip, zipAll, zipWith, zipWithIndex, zipWithIndex

Methods inherited from interface io.vavr.collection.Traversable
arrangeBy, average, containsAll, count, existsUnique, find, findLast, fold, foldLeft, forEachWithIndex, get, headOption, isOrdered, isSequential, isSingleValued, lastOption, max, maxBy, maxBy, min, minBy, minBy, mkCharSeq, mkCharSeq, mkCharSeq, mkString, mkString, mkString, narrow, nonEmpty, product, reduce, reduceLeft, reduceLeftOption, reduceOption, reduceRight, reduceRightOption, single, singleOption, sum, toLinkedMap, toMap, toSortedMap, toSortedMap, unzip, unzip3

Methods inherited from interface io.vavr.Value
collect, collect, corresponds, eq, exists, forAll, forEach, getOrElse, getOrElse, getOrElseThrow, getOrElseTry, getOrNull, narrow, out, out, stderr, stdout, toArray, toCharSeq, toCompletableFuture, toEither, toEither, toInvalid, toInvalid, toJavaArray, toJavaArray, toJavaArray, toJavaCollection, toJavaList, toJavaList, toJavaMap, toJavaMap, toJavaMap, toJavaOptional, toJavaParallelStream, toJavaSet, toJavaSet, toJavaStream, toLeft, toLeft, toLinkedMap, toLinkedMap, toLinkedSet, toList, toMap, toMap, toOption, toPriorityQueue, toPriorityQueue, toQueue, toRight, toRight, toSet, toSortedMap, toSortedMap, toSortedMap, toSortedMap, toSortedSet, toSortedSet, toStream, toTree, toTree, toTry, toTry, toValid, toValid, toValidation, toValidation, toVector

Methods inherited from interface io.vavr.Function1
andThen, arity, compose, constant, curried, identity, isMemoized, lift, liftTry, memoized, narrow, of, partial, reversed, tupled

- Method Detail
  - collector
```
public static <K,V> java.util.stream.Collector<Tuple2<K,V>,java.util.ArrayList<Tuple2<K,V>>,HashMap<K,V>> collector()
```
    Returns a Collector which may be used in conjunction with Stream.collect(java.util.stream.Collector) to obtain a HashMap.
    
    Type Parameters:
    
    K - The key type
    
    V - The value type
    
    Returns:
    
    A HashMap Collector.
  - collector
```
public static <K,V,T extends V> java.util.stream.Collector<T,java.util.ArrayList<T>,HashMap<K,V>> collector(java.util.function.Function<? super T,? extends K> keyMapper)
```
    Returns a Collector which may be used in conjunction with Stream.collect(java.util.stream.Collector) to obtain a HashMap.
    
    Type Parameters:
    
    K - The key type
    
    V - The value type
    
    T - Initial Stream elements type
    
    Parameters:
    
    keyMapper - The key mapper
    
    Returns:
    
    A HashMap Collector.
  - collector
```
public static <K,V,T> java.util.stream.Collector<T,java.util.ArrayList<T>,HashMap<K,V>> collector(java.util.function.Function<? super T,? extends K> keyMapper,
                                                                                                  java.util.function.Function<? super T,? extends V> valueMapper)
```
    Returns a Collector which may be used in conjunction with Stream.collect(java.util.stream.Collector) to obtain a HashMap.
    
    Type Parameters:
    
    K - The key type
    
    V - The value type
    
    T - Initial Stream elements type
    
    Parameters:
    
    keyMapper - The key mapper
    
    valueMapper - The value mapper
    
    Returns:
    
    A HashMap Collector.
  - empty
```
public static <K,V> HashMap<K,V> empty()
```
  - narrow
```
public static <K,V> HashMap<K,V> narrow(HashMap<? extends K,? extends V> hashMap)
```
    Narrows a widened HashMap<? extends K, ? extends V> to HashMap<K, V> by performing a type-safe cast. This is eligible because immutable/read-only collections are covariant.
    
    Type Parameters:
    
    K - Key type
    
    V - Value type
    
    Parameters:
    
    hashMap - A HashMap.
    
    Returns:
    
    the given hashMap instance as narrowed type HashMap<K, V>.
  - of
```
public static <K,V> HashMap<K,V> of(Tuple2<? extends K,? extends V> entry)
```
    Returns a singleton HashMap, i.e. a HashMap of one element.
    
    Type Parameters:
    
    K - The key type
    
    V - The value type
    
    Parameters:
    
    entry - A map entry.
    
    Returns:
    
    A new Map containing the given entry
  - ofAll
```
public static <K,V> HashMap<K,V> ofAll(java.util.Map<? extends K,? extends V> map)
```
    Returns a HashMap, from a source java.util.Map.
    
    Type Parameters:
    
    K - The key type
    
    V - The value type
    
    Parameters:
    
    map - A map
    
    Returns:
    
    A new Map containing the given map
  - ofAll
```
public static <T,K,V> HashMap<K,V> ofAll(java.util.stream.Stream<? extends T> stream,
                                         java.util.function.Function<? super T,? extends K> keyMapper,
                                         java.util.function.Function<? super T,? extends V> valueMapper)
```
    Returns a HashMap, from entries mapped from stream.
    
    Type Parameters:
    
    T - The stream element type
    
    K - The key type
    
    V - The value type
    
    Parameters:
    
    stream - the source stream
    
    keyMapper - the key mapper
    
    valueMapper - the value mapper
    
    Returns:
    
    A new Map
  - ofAll
```
public static <T,K,V> HashMap<K,V> ofAll(java.util.stream.Stream<? extends T> stream,
                                         java.util.function.Function<? super T,Tuple2<? extends K,? extends V>> entryMapper)
```
    Returns a HashMap, from entries mapped from stream.
    
    Type Parameters:
    
    T - The stream element type
    
    K - The key type
    
    V - The value type
    
    Parameters:
    
    stream - the source stream
    
    entryMapper - the entry mapper
    
    Returns:
    
    A new Map
  - of
```
public static <K,V> HashMap<K,V> of(K key,
                                    V value)
```
    Returns a singleton HashMap, i.e. a HashMap of one element.
    
    Type Parameters:
    
    K - The key type
    
    V - The value type
    
    Parameters:
    
    key - A singleton map key.
    
    value - A singleton map value.
    
    Returns:
    
    A new Map containing the given entry
  - of
```
public static <K,V> HashMap<K,V> of(K k1,
                                    V v1,
                                    K k2,
                                    V v2)
```
    Creates a HashMap of the given list of key-value pairs.
    
    Type Parameters:
    
    K - The key type
    
    V - The value type
    
    Parameters:
    
    k1 - a key for the map
    
    v1 - the value for k1
    
    k2 - a key for the map
    
    v2 - the value for k2
    
    Returns:
    
    A new Map containing the given entries
  - of
```
public static <K,V> HashMap<K,V> of(K k1,
                                    V v1,
                                    K k2,
                                    V v2,
                                    K k3,
                                    V v3)
```
    Creates a HashMap of the given list of key-value pairs.
    
    Type Parameters:
    
    K - The key type
    
    V - The value type
    
    Parameters:
    
    k1 - a key for the map
    
    v1 - the value for k1
    
    k2 - a key for the map
    
    v2 - the value for k2
    
    k3 - a key for the map
    
    v3 - the value for k3
    
    Returns:
    
    A new Map containing the given entries
  - of
```
public static <K,V> HashMap<K,V> of(K k1,
                                    V v1,
                                    K k2,
                                    V v2,
                                    K k3,
                                    V v3,
                                    K k4,
                                    V v4)
```
    Creates a HashMap of the given list of key-value pairs.
    
    Type Parameters:
    
    K - The key type
    
    V - The value type
    
    Parameters:
    
    k1 - a key for the map
    
    v1 - the value for k1
    
    k2 - a key for the map
    
    v2 - the value for k2
    
    k3 - a key for the map
    
    v3 - the value for k3
    
    k4 - a key for the map
    
    v4 - the value for k4
    
    Returns:
    
    A new Map containing the given entries
  - of
```
public static <K,V> HashMap<K,V> of(K k1,
                                    V v1,
                                    K k2,
                                    V v2,
                                    K k3,
                                    V v3,
                                    K k4,
                                    V v4,
                                    K k5,
                                    V v5)
```
    Creates a HashMap of the given list of key-value pairs.
    
    Type Parameters:
    
    K - The key type
    
    V - The value type
    
    Parameters:
    
    k1 - a key for the map
    
    v1 - the value for k1
    
    k2 - a key for the map
    
    v2 - the value for k2
    
    k3 - a key for the map
    
    v3 - the value for k3
    
    k4 - a key for the map
    
    v4 - the value for k4
    
    k5 - a key for the map
    
    v5 - the value for k5
    
    Returns:
    
    A new Map containing the given entries
  - of
```
public static <K,V> HashMap<K,V> of(K k1,
                                    V v1,
                                    K k2,
                                    V v2,
                                    K k3,
                                    V v3,
                                    K k4,
                                    V v4,
                                    K k5,
                                    V v5,
                                    K k6,
                                    V v6)
```
    Creates a HashMap of the given list of key-value pairs.
    
    Type Parameters:
    
    K - The key type
    
    V - The value type
    
    Parameters:
    
    k1 - a key for the map
    
    v1 - the value for k1
    
    k2 - a key for the map
    
    v2 - the value for k2
    
    k3 - a key for the map
    
    v3 - the value for k3
    
    k4 - a key for the map
    
    v4 - the value for k4
    
    k5 - a key for the map
    
    v5 - the value for k5
    
    k6 - a key for the map
    
    v6 - the value for k6
    
    Returns:
    
    A new Map containing the given entries
  - of
```
public static <K,V> HashMap<K,V> of(K k1,
                                    V v1,
                                    K k2,
                                    V v2,
                                    K k3,
                                    V v3,
                                    K k4,
                                    V v4,
                                    K k5,
                                    V v5,
                                    K k6,
                                    V v6,
                                    K k7,
                                    V v7)
```
    Creates a HashMap of the given list of key-value pairs.
    
    Type Parameters:
    
    K - The key type
    
    V - The value type
    
    Parameters:
    
    k1 - a key for the map
    
    v1 - the value for k1
    
    k2 - a key for the map
    
    v2 - the value for k2
    
    k3 - a key for the map
    
    v3 - the value for k3
    
    k4 - a key for the map
    
    v4 - the value for k4
    
    k5 - a key for the map
    
    v5 - the value for k5
    
    k6 - a key for the map
    
    v6 - the value for k6
    
    k7 - a key for the map
    
    v7 - the value for k7
    
    Returns:
    
    A new Map containing the given entries
  - of
```
public static <K,V> HashMap<K,V> of(K k1,
                                    V v1,
                                    K k2,
                                    V v2,
                                    K k3,
                                    V v3,
                                    K k4,
                                    V v4,
                                    K k5,
                                    V v5,
                                    K k6,
                                    V v6,
                                    K k7,
                                    V v7,
                                    K k8,
                                    V v8)
```
    Creates a HashMap of the given list of key-value pairs.
    
    Type Parameters:
    
    K - The key type
    
    V - The value type
    
    Parameters:
    
    k1 - a key for the map
    
    v1 - the value for k1
    
    k2 - a key for the map
    
    v2 - the value for k2
    
    k3 - a key for the map
    
    v3 - the value for k3
    
    k4 - a key for the map
    
    v4 - the value for k4
    
    k5 - a key for the map
    
    v5 - the value for k5
    
    k6 - a key for the map
    
    v6 - the value for k6
    
    k7 - a key for the map
    
    v7 - the value for k7
    
    k8 - a key for the map
    
    v8 - the value for k8
    
    Returns:
    
    A new Map containing the given entries
  - of
```
public static <K,V> HashMap<K,V> of(K k1,
                                    V v1,
                                    K k2,
                                    V v2,
                                    K k3,
                                    V v3,
                                    K k4,
                                    V v4,
                                    K k5,
                                    V v5,
                                    K k6,
                                    V v6,
                                    K k7,
                                    V v7,
                                    K k8,
                                    V v8,
                                    K k9,
                                    V v9)
```
    Creates a HashMap of the given list of key-value pairs.
    
    Type Parameters:
    
    K - The key type
    
    V - The value type
    
    Parameters:
    
    k1 - a key for the map
    
    v1 - the value for k1
    
    k2 - a key for the map
    
    v2 - the value for k2
    
    k3 - a key for the map
    
    v3 - the value for k3
    
    k4 - a key for the map
    
    v4 - the value for k4
    
    k5 - a key for the map
    
    v5 - the value for k5
    
    k6 - a key for the map
    
    v6 - the value for k6
    
    k7 - a key for the map
    
    v7 - the value for k7
    
    k8 - a key for the map
    
    v8 - the value for k8
    
    k9 - a key for the map
    
    v9 - the value for k9
    
    Returns:
    
    A new Map containing the given entries
  - of
```
public static <K,V> HashMap<K,V> of(K k1,
                                    V v1,
                                    K k2,
                                    V v2,
                                    K k3,
                                    V v3,
                                    K k4,
                                    V v4,
                                    K k5,
                                    V v5,
                                    K k6,
                                    V v6,
                                    K k7,
                                    V v7,
                                    K k8,
                                    V v8,
                                    K k9,
                                    V v9,
                                    K k10,
                                    V v10)
```
    Creates a HashMap of the given list of key-value pairs.
    
    Type Parameters:
    
    K - The key type
    
    V - The value type
    
    Parameters:
    
    k1 - a key for the map
    
    v1 - the value for k1
    
    k2 - a key for the map
    
    v2 - the value for k2
    
    k3 - a key for the map
    
    v3 - the value for k3
    
    k4 - a key for the map
    
    v4 - the value for k4
    
    k5 - a key for the map
    
    v5 - the value for k5
    
    k6 - a key for the map
    
    v6 - the value for k6
    
    k7 - a key for the map
    
    v7 - the value for k7
    
    k8 - a key for the map
    
    v8 - the value for k8
    
    k9 - a key for the map
    
    v9 - the value for k9
    
    k10 - a key for the map
    
    v10 - the value for k10
    
    Returns:
    
    A new Map containing the given entries
  - tabulate
```
public static <K,V> HashMap<K,V> tabulate(int n,
                                          java.util.function.Function<? super java.lang.Integer,? extends Tuple2<? extends K,? extends V>> f)
```
    Returns an HashMap containing n values of a given Function f over a range of integer values from 0 to n - 1.
    
    Type Parameters:
    
    K - The key type
    
    V - The value type
    
    Parameters:
    
    n - The number of elements in the HashMap
    
    f - The Function computing element values
    
    Returns:
    
    An HashMap consisting of elements f(0),f(1), ..., f(n - 1)
    
    Throws:
    
    java.lang.NullPointerException - if f is null
  - fill
```
public static <K,V> HashMap<K,V> fill(int n,
                                      java.util.function.Supplier<? extends Tuple2<? extends K,? extends V>> s)
```
    Returns a HashMap containing tuples returned by n calls to a given Supplier s.
    
    Type Parameters:
    
    K - The key type
    
    V - The value type
    
    Parameters:
    
    n - The number of elements in the HashMap
    
    s - The Supplier computing element values
    
    Returns:
    
    An HashMap of size n, where each element contains the result supplied by s.
    
    Throws:
    
    java.lang.NullPointerException - if s is null
  - ofEntries
```
@SafeVarargs
public static <K,V> HashMap<K,V> ofEntries(java.util.Map.Entry<? extends K,? extends V>... entries)
```
    Creates a HashMap of the given entries.
    
    Type Parameters:
    
    K - The key type
    
    V - The value type
    
    Parameters:
    
    entries - Map entries
    
    Returns:
    
    A new Map containing the given entries
  - ofEntries
```
@SafeVarargs
public static <K,V> HashMap<K,V> ofEntries(Tuple2<? extends K,? extends V>... entries)
```
    Creates a HashMap of the given entries.
    
    Type Parameters:
    
    K - The key type
    
    V - The value type
    
    Parameters:
    
    entries - Map entries
    
    Returns:
    
    A new Map containing the given entries
  - ofEntries
```
public static <K,V> HashMap<K,V> ofEntries(java.lang.Iterable<? extends Tuple2<? extends K,? extends V>> entries)
```
    Creates a HashMap of the given entries.
    
    Type Parameters:
    
    K - The key type
    
    V - The value type
    
    Parameters:
    
    entries - Map entries
    
    Returns:
    
    A new Map containing the given entries
  - bimap
```
public <K2,V2> HashMap<K2,V2> bimap(java.util.function.Function<? super K,? extends K2> keyMapper,
                                    java.util.function.Function<? super V,? extends V2> valueMapper)
```
    Description copied from interface: Map
    
    Maps this Map to a new Map with different component type by applying a function to its elements.
    
    Specified by:
    
    bimap in interface Map<K,V>
    
    Type Parameters:
    
    K2 - key's component type of the map result
    
    V2 - value's component type of the map result
    
    Parameters:
    
    keyMapper - a Function that maps the keys of type K to keys of type K2
    
    valueMapper - a Function that the values of type V to values of type V2
    
    Returns:
    
    a new Map
  - computeIfAbsent
```
public Tuple2<V,HashMap<K,V>> computeIfAbsent(K key,
                                              java.util.function.Function<? super K,? extends V> mappingFunction)
```
    Description copied from interface: Map
    
    If the specified key is not already associated with a value, attempts to compute its value using the given mapping function and enters it into this map.
    
    Specified by:
    
    computeIfAbsent in interface Map<K,V>
    
    Parameters:
    
    key - key whose presence in this map is to be tested
    
    mappingFunction - mapping function
    
    Returns:
    
    the Tuple2 of current or modified map and existing or computed value associated with the specified key
  - computeIfPresent
```
public Tuple2<Option<V>,HashMap<K,V>> computeIfPresent(K key,
                                                       java.util.function.BiFunction<? super K,? super V,? extends V> remappingFunction)
```
    Description copied from interface: Map
    
    If the value for the specified key is present, attempts to compute a new mapping given the key and its current mapped value.
    
    Specified by:
    
    computeIfPresent in interface Map<K,V>
    
    Parameters:
    
    key - key whose presence in this map is to be tested
    
    remappingFunction - remapping function
    
    Returns:
    
    the Tuple2 of current or modified map and the Some of the value associated with the specified key, or None if none
  - containsKey
```
public boolean containsKey(K key)
```
    Description copied from interface: Map
    
    Returns true if this map contains a mapping for the specified key.
    
    Specified by:
    
    containsKey in interface Map<K,V>
    
    Parameters:
    
    key - key whose presence in this map is to be tested
    
    Returns:
    
    true if this map contains a mapping for the specified key
  - distinct
```
public HashMap<K,V> distinct()
```
    Description copied from interface: Traversable
    
    Returns a new version of this which contains no duplicates. Elements are compared using equals.
    
    Specified by:
    
    distinct in interface Map<K,V>
    
    Specified by:
    
    distinct in interface Traversable<Tuple2<K,V>>
    
    Returns:
    
    a new Traversable containing this elements without duplicates
  - distinctBy
```
public HashMap<K,V> distinctBy(java.util.Comparator<? super Tuple2<K,V>> comparator)
```
    Description copied from interface: Traversable
    
    Returns a new version of this which contains no duplicates. Elements are compared using the given comparator.
    
    Specified by:
    
    distinctBy in interface Map<K,V>
    
    Specified by:
    
    distinctBy in interface Traversable<Tuple2<K,V>>
    
    Parameters:
    
    comparator - A comparator
    
    Returns:
    
    a new Traversable containing this elements without duplicates
  - distinctBy
```
public <U> HashMap<K,V> distinctBy(java.util.function.Function<? super Tuple2<K,V>,? extends U> keyExtractor)
```
    Description copied from interface: Traversable
    
    Returns a new version of this which contains no duplicates. Elements mapped to keys which are compared using equals.
    The elements of the result are determined in the order of their occurrence - first match wins.
    
    Specified by:
    
    distinctBy in interface Map<K,V>
    
    Specified by:
    
    distinctBy in interface Traversable<Tuple2<K,V>>
    
    Type Parameters:
    
    U - key type
    
    Parameters:
    
    keyExtractor - A key extractor
    
    Returns:
    
    a new Traversable containing this elements without duplicates
  - drop
```
public HashMap<K,V> drop(int n)
```
    Description copied from interface: Traversable
    
    Drops the first n elements of this or all elements, if this length < n.
    
    Specified by:
    
    drop in interface Map<K,V>
    
    Specified by:
    
    drop in interface Traversable<Tuple2<K,V>>
    
    Parameters:
    
    n - The number of elements to drop.
    
    Returns:
    
    a new instance consisting of all elements of this except the first n ones, or else the empty instance, if this has less than n elements.
  - dropRight
```
public HashMap<K,V> dropRight(int n)
```
    Description copied from interface: Traversable
    
    Drops the last n elements of this or all elements, if this length < n.
    
    Specified by:
    
    dropRight in interface Map<K,V>
    
    Specified by:
    
    dropRight in interface Traversable<Tuple2<K,V>>
    
    Parameters:
    
    n - The number of elements to drop.
    
    Returns:
    
    a new instance consisting of all elements of this except the last n ones, or else the empty instance, if this has less than n elements.
  - dropUntil
```
public HashMap<K,V> dropUntil(java.util.function.Predicate<? super Tuple2<K,V>> predicate)
```
    Description copied from interface: Traversable
    
    Drops elements until the predicate holds for the current element.
    
    Specified by:
    
    dropUntil in interface Map<K,V>
    
    Specified by:
    
    dropUntil in interface Traversable<Tuple2<K,V>>
    
    Parameters:
    
    predicate - A condition tested subsequently for this elements.
    
    Returns:
    
    a new instance consisting of all elements starting from the first one which does satisfy the given predicate.
  - dropWhile
```
public HashMap<K,V> dropWhile(java.util.function.Predicate<? super Tuple2<K,V>> predicate)
```
    Description copied from interface: Traversable
    
    Drops elements while the predicate holds for the current element.
    Note: This is essentially the same as dropUntil(predicate.negate()). It is intended to be used with method references, which cannot be negated directly.
    
    Specified by:
    
    dropWhile in interface Map<K,V>
    
    Specified by:
    
    dropWhile in interface Traversable<Tuple2<K,V>>
    
    Parameters:
    
    predicate - A condition tested subsequently for this elements.
    
    Returns:
    
    a new instance consisting of all elements starting from the first one which does not satisfy the given predicate.
  - filter
```
public HashMap<K,V> filter(java.util.function.BiPredicate<? super K,? super V> predicate)
```
    Description copied from interface: Map
    
    Returns a new Map consisting of all elements which satisfy the given predicate.
    
    Specified by:
    
    filter in interface Map<K,V>
    
    Parameters:
    
    predicate - the predicate used to test elements
    
    Returns:
    
    a new Map
  - filterNot
```
public HashMap<K,V> filterNot(java.util.function.BiPredicate<? super K,? super V> predicate)
```
    Description copied from interface: Map
    
    Returns a new Map consisting of all elements which do not satisfy the given predicate.
    
    Specified by:
    
    filterNot in interface Map<K,V>
    
    Parameters:
    
    predicate - the predicate used to test elements
    
    Returns:
    
    a new Map
  - filter
```
public HashMap<K,V> filter(java.util.function.Predicate<? super Tuple2<K,V>> predicate)
```
    Description copied from interface: Traversable
    
    Returns a new traversable consisting of all elements which satisfy the given predicate.
    
    Specified by:
    
    filter in interface Map<K,V>
    
    Specified by:
    
    filter in interface Traversable<Tuple2<K,V>>
    
    Parameters:
    
    predicate - A predicate
    
    Returns:
    
    a new traversable
  - filterNot
```
public HashMap<K,V> filterNot(java.util.function.Predicate<? super Tuple2<K,V>> predicate)
```
    Description copied from interface: Traversable
    Returns a new traversable consisting of all elements which do not satisfy the given predicate.
    The default implementation is equivalent to
```
 filter(predicate.negate()
```
    Specified by:
    
    filterNot in interface Map<K,V>
    
    Specified by:
    
    filterNot in interface Traversable<Tuple2<K,V>>
    
    Parameters:
    
    predicate - A predicate
    
    Returns:
    
    a new traversable
  - filterKeys
```
public HashMap<K,V> filterKeys(java.util.function.Predicate<? super K> predicate)
```
    Description copied from interface: Map
    
    Returns a new Map consisting of all elements with keys which satisfy the given predicate.
    
    Specified by:
    
    filterKeys in interface Map<K,V>
    
    Parameters:
    
    predicate - the predicate used to test keys of elements
    
    Returns:
    
    a new Map
  - filterNotKeys
```
public HashMap<K,V> filterNotKeys(java.util.function.Predicate<? super K> predicate)
```
    Description copied from interface: Map
    
    Returns a new Map consisting of all elements with keys which do not satisfy the given predicate.
    
    Specified by:
    
    filterNotKeys in interface Map<K,V>
    
    Parameters:
    
    predicate - the predicate used to test keys of elements
    
    Returns:
    
    a new Map
  - filterValues
```
public HashMap<K,V> filterValues(java.util.function.Predicate<? super V> predicate)
```
    Description copied from interface: Map
    
    Returns a new Map consisting of all elements with values which satisfy the given predicate.
    
    Specified by:
    
    filterValues in interface Map<K,V>
    
    Parameters:
    
    predicate - the predicate used to test values of elements
    
    Returns:
    
    a new Map
  - filterNotValues
```
public HashMap<K,V> filterNotValues(java.util.function.Predicate<? super V> predicate)
```
    Description copied from interface: Map
    
    Returns a new Map consisting of all elements with values which do not satisfy the given predicate.
    
    Specified by:
    
    filterNotValues in interface Map<K,V>
    
    Parameters:
    
    predicate - the predicate used to test values of elements
    
    Returns:
    
    a new Map
  - flatMap
```
public <K2,V2> HashMap<K2,V2> flatMap(java.util.function.BiFunction<? super K,? super V,? extends java.lang.Iterable<Tuple2<K2,V2>>> mapper)
```
    Description copied from interface: Map
    
    FlatMaps this Map to a new Map with different component type.
    
    Specified by:
    
    flatMap in interface Map<K,V>
    
    Type Parameters:
    
    K2 - key's component type of the mapped Map
    
    V2 - value's component type of the mapped Map
    
    Parameters:
    
    mapper - A mapper
    
    Returns:
    
    A new Map.
  - get
```
public Option<V> get(K key)
```
    Description copied from interface: Map
    
    Returns the Some of value to which the specified key is mapped, or None if this map contains no mapping for the key.
    
    Specified by:
    
    get in interface Map<K,V>
    
    Parameters:
    
    key - the key whose associated value is to be returned
    
    Returns:
    
    the Some of value to which the specified key is mapped, or None if this map contains no mapping for the key
  - getOrElse
```
public V getOrElse(K key,
                   V defaultValue)
```
    Description copied from interface: Map
    
    Returns the value associated with a key, or a default value if the key is not contained in the map.
    
    Specified by:
    
    getOrElse in interface Map<K,V>
    
    Parameters:
    
    key - the key
    
    defaultValue - a default value
    
    Returns:
    
    the value associated with key if it exists, otherwise the default value.
  - groupBy
```
public <C> Map<C,HashMap<K,V>> groupBy(java.util.function.Function<? super Tuple2<K,V>,? extends C> classifier)
```
    Description copied from interface: Traversable
    
    Groups this elements by classifying the elements.
    
    Specified by:
    
    groupBy in interface Map<K,V>
    
    Specified by:
    
    groupBy in interface Traversable<Tuple2<K,V>>
    
    Type Parameters:
    
    C - classified class type
    
    Parameters:
    
    classifier - A function which classifies elements into classes
    
    Returns:
    
    A Map containing the grouped elements
    
    See Also:
    
    Traversable.arrangeBy(Function)
  - grouped
```
public Iterator<HashMap<K,V>> grouped(int size)
```
    Description copied from interface: Traversable
    Groups this Traversable into fixed size blocks.
    Let length be the length of this Iterable. Then grouped is defined as follows:
    - If this.isEmpty(), the resulting Iterator is empty.
    - If size <= length, the resulting Iterator will contain length / size blocks of size size and maybe a non-empty block of size length % size, if there are remaining elements.
    - If size > length, the resulting Iterator will contain one block of size length.
    Examples:
```
 
 [].grouped(1) = []
 [].grouped(0) throws
 [].grouped(-1) throws
 [1,2,3,4].grouped(2) = [[1,2],[3,4]]
 [1,2,3,4,5].grouped(2) = [[1,2],[3,4],[5]]
 [1,2,3,4].grouped(5) = [[1,2,3,4]]
 
 
```
    Please note that grouped(int) is a special case of Traversable.sliding(int, int), i.e. grouped(size) is the same as sliding(size, size).
    Specified by:
    
    grouped in interface Map<K,V>
    
    Specified by:
    
    grouped in interface Traversable<Tuple2<K,V>>
    
    Parameters:
    
    size - a positive block size
    
    Returns:
    
    A new Iterator of grouped blocks of the given size
  - head
```
public Tuple2<K,V> head()
```
    Description copied from interface: Traversable
    
    Returns the first element of a non-empty Traversable.
    
    Specified by:
    
    head in interface Traversable<Tuple2<K,V>>
    
    Returns:
    
    The first element of this Traversable.
  - init
```
public HashMap<K,V> init()
```
    XXX We return tail() here. I believe that this is correct. See identical code in HashSet.init()
    
    Specified by:
    
    init in interface Map<K,V>
    
    Specified by:
    
    init in interface Traversable<Tuple2<K,V>>
    
    Returns:
    
    a new instance containing all elements except the last.
  - initOption
```
public Option<HashMap<K,V>> initOption()
```
    Description copied from interface: Traversable
    
    Dual of Traversable.tailOption(), returning all elements except the last as Option.
    
    Specified by:
    
    initOption in interface Map<K,V>
    
    Specified by:
    
    initOption in interface Traversable<Tuple2<K,V>>
    
    Returns:
    
    Some(traversable) or None if this is empty.
  - isAsync
```
public boolean isAsync()
```
    A HashMap is computed synchronously.
    
    Specified by:
    
    isAsync in interface Value<Tuple2<K,V>>
    
    Returns:
    
    false
  - isEmpty
```
public boolean isEmpty()
```
    Description copied from interface: Traversable
    
    Checks if this Traversable is empty.
    
    Specified by:
    
    isEmpty in interface Traversable<Tuple2<K,V>>
    
    Specified by:
    
    isEmpty in interface Value<Tuple2<K,V>>
    
    Returns:
    
    true, if this Traversable contains no elements, false otherwise.
  - isLazy
```
public boolean isLazy()
```
    A HashMap is computed eagerly.
    
    Specified by:
    
    isLazy in interface Value<Tuple2<K,V>>
    
    Returns:
    
    false
  - iterator
```
public Iterator<Tuple2<K,V>> iterator()
```
    Description copied from interface: Traversable
    
    An iterator by means of head() and tail(). Subclasses may want to override this method.
    
    Specified by:
    
    iterator in interface Map<K,V>
    
    Specified by:
    
    iterator in interface Traversable<Tuple2<K,V>>
    
    Specified by:
    
    iterator in interface Value<Tuple2<K,V>>
    
    Specified by:
    
    iterator in interface java.lang.Iterable<Tuple2<K,V>>
    
    Returns:
    
    A new Iterator of this Traversable elements.
  - keySet
```
public Set<K> keySet()
```
    Description copied from interface: Map
    
    Returns the keys contained in this map.
    
    Specified by:
    
    keySet in interface Map<K,V>
    
    Returns:
    
    Set of the keys contained in this map.
  - keysIterator
```
public Iterator<K> keysIterator()
```
    Description copied from interface: Map
    
    Returns the keys contained in this map as an iterator.
    
    Specified by:
    
    keysIterator in interface Map<K,V>
    
    Returns:
    
    Iterator of the keys contained in this map.
  - last
```
public Tuple2<K,V> last()
```
    Description copied from interface: Traversable
    
    Dual of Traversable.head(), returning the last element.
    
    Specified by:
    
    last in interface Traversable<Tuple2<K,V>>
    
    Returns:
    
    the last element.
  - map
```
public <K2,V2> HashMap<K2,V2> map(java.util.function.BiFunction<? super K,? super V,Tuple2<K2,V2>> mapper)
```
    Description copied from interface: Map
    
    Maps the entries of this Map to form a new Map.
    
    Specified by:
    
    map in interface Map<K,V>
    
    Type Parameters:
    
    K2 - key's component type of the map result
    
    V2 - value's component type of the map result
    
    Parameters:
    
    mapper - a Function that maps entries of type (K, V) to entries of type (K2, V2)
    
    Returns:
    
    a new Map
  - mapKeys
```
public <K2> HashMap<K2,V> mapKeys(java.util.function.Function<? super K,? extends K2> keyMapper)
```
    Description copied from interface: Map
    
    Maps the keys of this Map while preserving the corresponding values.
    The size of the result map may be smaller if keyMapper maps two or more distinct keys to the same new key. In this case the value at the latest of the original keys is retained. Order of keys is predictable in TreeMap (by comparator) and LinkedHashMap (insertion-order) and not predictable in HashMap.
    
    Specified by:
    
    mapKeys in interface Map<K,V>
    
    Type Parameters:
    
    K2 - the new key type
    
    Parameters:
    
    keyMapper - a Function that maps keys of type V to keys of type V2
    
    Returns:
    
    a new Map
  - mapKeys
```
public <K2> HashMap<K2,V> mapKeys(java.util.function.Function<? super K,? extends K2> keyMapper,
                                  java.util.function.BiFunction<? super V,? super V,? extends V> valueMerge)
```
    Description copied from interface: Map
    
    Maps the keys of this Map while preserving the corresponding values and applying a value merge function on collisions.
    The size of the result map may be smaller if keyMapper maps two or more distinct keys to the same new key. In this case the associated values will be combined using valueMerge.
    
    Specified by:
    
    mapKeys in interface Map<K,V>
    
    Type Parameters:
    
    K2 - the new key type
    
    Parameters:
    
    keyMapper - a Function that maps keys of type V to keys of type V2
    
    valueMerge - a BiFunction that merges values
    
    Returns:
    
    a new Map
  - mapValues
```
public <V2> HashMap<K,V2> mapValues(java.util.function.Function<? super V,? extends V2> valueMapper)
```
    Description copied from interface: Map
    
    Maps the values of this Map while preserving the corresponding keys.
    
    Specified by:
    
    mapValues in interface Map<K,V>
    
    Type Parameters:
    
    V2 - the new value type
    
    Parameters:
    
    valueMapper - a Function that maps values of type V to values of type V2
    
    Returns:
    
    a new Map
  - merge
```
public HashMap<K,V> merge(Map<? extends K,? extends V> that)
```
    Description copied from interface: Map
    
    Creates a new map which by merging the entries of this map and that map.
    If collisions occur, the value of this map is taken.
    
    Specified by:
    
    merge in interface Map<K,V>
    
    Parameters:
    
    that - the other map
    
    Returns:
    
    A merged map
  - merge
```
public <U extends V> HashMap<K,V> merge(Map<? extends K,U> that,
                                        java.util.function.BiFunction<? super V,? super U,? extends V> collisionResolution)
```
    Description copied from interface: Map
    
    Creates a new map which by merging the entries of this map and that map.
    Uses the specified collision resolution function if two keys are the same. The collision resolution function will always take the first argument from this map and the second from that map.
    
    Specified by:
    
    merge in interface Map<K,V>
    
    Type Parameters:
    
    U - value type of that Map
    
    Parameters:
    
    that - the other map
    
    collisionResolution - the collision resolution function
    
    Returns:
    
    A merged map
  - orElse
```
public HashMap<K,V> orElse(java.lang.Iterable<? extends Tuple2<K,V>> other)
```
    Description copied from interface: Traversable
    
    Returns this Traversable if it is nonempty, otherwise return the alternative.
    
    Specified by:
    
    orElse in interface Map<K,V>
    
    Specified by:
    
    orElse in interface Traversable<Tuple2<K,V>>
    
    Parameters:
    
    other - An alternative Traversable
    
    Returns:
    
    this Traversable if it is nonempty, otherwise return the alternative.
  - orElse
```
public HashMap<K,V> orElse(java.util.function.Supplier<? extends java.lang.Iterable<? extends Tuple2<K,V>>> supplier)
```
    Description copied from interface: Traversable
    
    Returns this Traversable if it is nonempty, otherwise return the result of evaluating supplier.
    
    Specified by:
    
    orElse in interface Map<K,V>
    
    Specified by:
    
    orElse in interface Traversable<Tuple2<K,V>>
    
    Parameters:
    
    supplier - An alternative Traversable supplier
    
    Returns:
    
    this Traversable if it is nonempty, otherwise return the result of evaluating supplier.
  - partition
```
public Tuple2<HashMap<K,V>,HashMap<K,V>> partition(java.util.function.Predicate<? super Tuple2<K,V>> predicate)
```
    Description copied from interface: Traversable
    
    Creates a partition of this Traversable by splitting this elements in two in distinct traversables according to a predicate.
    
    Specified by:
    
    partition in interface Map<K,V>
    
    Specified by:
    
    partition in interface Traversable<Tuple2<K,V>>
    
    Parameters:
    
    predicate - A predicate which classifies an element if it is in the first or the second traversable.
    
    Returns:
    
    A disjoint union of two traversables. The first Traversable contains all elements that satisfy the given predicate, the second Traversable contains all elements that don't. The original order of elements is preserved.
  - peek
```
public HashMap<K,V> peek(java.util.function.Consumer<? super Tuple2<K,V>> action)
```
    Description copied from interface: Value
    
    Performs the given action on the first element if this is an eager implementation. Performs the given action on all elements (the first immediately, successive deferred), if this is a lazy implementation.
    
    Specified by:
    
    peek in interface Map<K,V>
    
    Specified by:
    
    peek in interface Traversable<Tuple2<K,V>>
    
    Specified by:
    
    peek in interface Value<Tuple2<K,V>>
    
    Parameters:
    
    action - The action that will be performed on the element(s).
    
    Returns:
    
    this instance
  - put
```
public <U extends V> HashMap<K,V> put(K key,
                                      U value,
                                      java.util.function.BiFunction<? super V,? super U,? extends V> merge)
```
    Description copied from interface: Map
    
    Associates the specified value with the specified key in this map. If the map previously contained a mapping for the key, the merge function is used to combine the previous value to the value to be inserted, and the result of that call is inserted in the map.
    
    Specified by:
    
    put in interface Map<K,V>
    
    Type Parameters:
    
    U - the value type
    
    Parameters:
    
    key - key with which the specified value is to be associated
    
    value - value to be associated with the specified key
    
    merge - function taking the old and new values and merging them.
    
    Returns:
    
    A new Map containing these elements and that entry.
  - put
```
public HashMap<K,V> put(K key,
                        V value)
```
    Description copied from interface: Map
    
    Associates the specified value with the specified key in this map. If the map previously contained a mapping for the key, the old value is replaced by the specified value.
    
    Specified by:
    
    put in interface Map<K,V>
    
    Parameters:
    
    key - key with which the specified value is to be associated
    
    value - value to be associated with the specified key
    
    Returns:
    
    A new Map containing these elements and that entry.
  - put
```
public HashMap<K,V> put(Tuple2<? extends K,? extends V> entry)
```
    Description copied from interface: Map
    
    Convenience method for put(entry._1, entry._2).
    
    Specified by:
    
    put in interface Map<K,V>
    
    Parameters:
    
    entry - A Tuple2 containing the key and value
    
    Returns:
    
    A new Map containing these elements and that entry.
  - put
```
public <U extends V> HashMap<K,V> put(Tuple2<? extends K,U> entry,
                                      java.util.function.BiFunction<? super V,? super U,? extends V> merge)
```
    Description copied from interface: Map
    
    Convenience method for put(entry._1, entry._2, merge).
    
    Specified by:
    
    put in interface Map<K,V>
    
    Type Parameters:
    
    U - the value type
    
    Parameters:
    
    entry - A Tuple2 containing the key and value
    
    merge - function taking the old and new values and merging them.
    
    Returns:
    
    A new Map containing these elements and that entry.
  - remove
```
public HashMap<K,V> remove(K key)
```
    Description copied from interface: Map
    
    Removes the mapping for a key from this map if it is present.
    
    Specified by:
    
    remove in interface Map<K,V>
    
    Parameters:
    
    key - key whose mapping is to be removed from the map
    
    Returns:
    
    A new Map containing these elements without the entry specified by that key.
  - removeAll
```
public HashMap<K,V> removeAll(java.lang.Iterable<? extends K> c)
```
    Description copied from interface: Map
    
    Removes the mapping for a key from this map if it is present.
    
    Specified by:
    
    removeAll in interface Map<K,V>
    
    Parameters:
    
    c - keys are to be removed from the map
    
    Returns:
    
    A new Map containing these elements without the entries specified by that keys.
  - replace
```
public HashMap<K,V> replace(Tuple2<K,V> currentElement,
                            Tuple2<K,V> newElement)
```
    Description copied from interface: Traversable
    
    Replaces the first occurrence (if exists) of the given currentElement with newElement.
    
    Specified by:
    
    replace in interface Map<K,V>
    
    Specified by:
    
    replace in interface Traversable<Tuple2<K,V>>
    
    Parameters:
    
    currentElement - An element to be substituted.
    
    newElement - A replacement for currentElement.
    
    Returns:
    
    a Traversable containing all elements of this where the first occurrence of currentElement is replaced with newElement.
  - replaceAll
```
public HashMap<K,V> replaceAll(Tuple2<K,V> currentElement,
                               Tuple2<K,V> newElement)
```
    Description copied from interface: Traversable
    
    Replaces all occurrences of the given currentElement with newElement.
    
    Specified by:
    
    replaceAll in interface Map<K,V>
    
    Specified by:
    
    replaceAll in interface Traversable<Tuple2<K,V>>
    
    Parameters:
    
    currentElement - An element to be substituted.
    
    newElement - A replacement for currentElement.
    
    Returns:
    
    a Traversable containing all elements of this where all occurrences of currentElement are replaced with newElement.
  - replaceValue
```
public HashMap<K,V> replaceValue(K key,
                                 V value)
```
    Description copied from interface: Map
    
    Replaces the entry for the specified key only if it is currently mapped to some value.
    
    Specified by:
    
    replaceValue in interface Map<K,V>
    
    Parameters:
    
    key - the key of the element to be substituted.
    
    value - the new value to be associated with the key
    
    Returns:
    
    a new map containing key mapped to value if key was contained before. The old map otherwise.
  - replace
```
public HashMap<K,V> replace(K key,
                            V oldValue,
                            V newValue)
```
    Description copied from interface: Map
    
    Replaces the entry for the specified key only if currently mapped to the specified value.
    
    Specified by:
    
    replace in interface Map<K,V>
    
    Parameters:
    
    key - the key of the element to be substituted.
    
    oldValue - the expected current value that the key is currently mapped to
    
    newValue - the new value to be associated with the key
    
    Returns:
    
    a new map containing key mapped to newValue if key was contained before and oldValue matched. The old map otherwise.
  - replaceAll
```
public HashMap<K,V> replaceAll(java.util.function.BiFunction<? super K,? super V,? extends V> function)
```
    Description copied from interface: Map
    
    Replaces each entry's value with the result of invoking the given function on that entry until all entries have been processed or the function throws an exception.
    
    Specified by:
    
    replaceAll in interface Map<K,V>
    
    Parameters:
    
    function - function transforming key and current value to a new value
    
    Returns:
    
    a new map with the same keySet but transformed values.
  - retainAll
```
public HashMap<K,V> retainAll(java.lang.Iterable<? extends Tuple2<K,V>> elements)
```
    Description copied from interface: Traversable
    
    Keeps all occurrences of the given elements from this.
    
    Specified by:
    
    retainAll in interface Map<K,V>
    
    Specified by:
    
    retainAll in interface Traversable<Tuple2<K,V>>
    
    Parameters:
    
    elements - Elements to be kept.
    
    Returns:
    
    a Traversable containing all occurrences of the given elements.
  - scan
```
public HashMap<K,V> scan(Tuple2<K,V> zero,
                         java.util.function.BiFunction<? super Tuple2<K,V>,? super Tuple2<K,V>,? extends Tuple2<K,V>> operation)
```
    Description copied from interface: Traversable
    
    Computes a prefix scan of the elements of the collection. Note: The neutral element z may be applied more than once.
    
    Specified by:
    
    scan in interface Map<K,V>
    
    Specified by:
    
    scan in interface Traversable<Tuple2<K,V>>
    
    Parameters:
    
    zero - neutral element for the operator op
    
    operation - the associative operator for the scan
    
    Returns:
    
    a new traversable collection containing the prefix scan of the elements in this traversable collection
  - size
```
public int size()
```
    Description copied from interface: Traversable
    
    Computes the number of elements of this Traversable.
    Same as Traversable.length().
    
    Specified by:
    
    size in interface Map<K,V>
    
    Specified by:
    
    size in interface Traversable<Tuple2<K,V>>
    
    Returns:
    
    the number of elements
  - slideBy
```
public Iterator<HashMap<K,V>> slideBy(java.util.function.Function<? super Tuple2<K,V>,?> classifier)
```
    Description copied from interface: Traversable
    Slides a non-overlapping window of a variable size over this Traversable.
    Each window contains elements with the same class, as determined by classifier. Two consecutive values in this Traversable will be in the same window only if classifier returns equal values for them. Otherwise, the values will constitute the last element of the previous window and the first element of the next window.
    Examples:
```
 [].slideBy(Function.identity()) = []
 [1,2,3,4,4,5].slideBy(Function.identity()) = [[1],[2],[3],[4,4],[5]]
 [1,2,3,10,12,5,7,20,29].slideBy(x -> x/10) = [[1,2,3],[10,12],[5,7],[20,29]]
 
```
    Specified by:
    
    slideBy in interface Map<K,V>
    
    Specified by:
    
    slideBy in interface Traversable<Tuple2<K,V>>
    
    Parameters:
    
    classifier - A function which classifies elements into classes
    
    Returns:
    
    A new Iterator of windows of the grouped elements
  - sliding
```
public Iterator<HashMap<K,V>> sliding(int size)
```
    Description copied from interface: Traversable
    
    Slides a window of a specific size and step size 1 over this Traversable by calling Traversable.sliding(int, int).
    
    Specified by:
    
    sliding in interface Map<K,V>
    
    Specified by:
    
    sliding in interface Traversable<Tuple2<K,V>>
    
    Parameters:
    
    size - a positive window size
    
    Returns:
    
    a new Iterator of windows of a specific size using step size 1
  - sliding
```
public Iterator<HashMap<K,V>> sliding(int size,
                                      int step)
```
    Description copied from interface: Traversable
    Slides a window of a specific size and step size over this Traversable.
    Examples:
```
 
 [].sliding(1,1) = []
 [1,2,3,4,5].sliding(2,3) = [[1,2],[4,5]]
 [1,2,3,4,5].sliding(2,4) = [[1,2],[5]]
 [1,2,3,4,5].sliding(2,5) = [[1,2]]
 [1,2,3,4].sliding(5,3) = [[1,2,3,4]]
 
 
```
    Specified by:
    
    sliding in interface Map<K,V>
    
    Specified by:
    
    sliding in interface Traversable<Tuple2<K,V>>
    
    Parameters:
    
    size - a positive window size
    
    step - a positive step size
    
    Returns:
    
    a new Iterator of windows of a specific size using a specific step size
  - span
```
public Tuple2<HashMap<K,V>,HashMap<K,V>> span(java.util.function.Predicate<? super Tuple2<K,V>> predicate)
```
    Description copied from interface: Traversable
    
    Returns a tuple where the first element is the longest prefix of elements that satisfy the given predicate and the second element is the remainder.
    
    Specified by:
    
    span in interface Map<K,V>
    
    Specified by:
    
    span in interface Traversable<Tuple2<K,V>>
    
    Parameters:
    
    predicate - A predicate.
    
    Returns:
    
    a Tuple containing the longest prefix of elements that satisfy p and the remainder.
  - spliterator
```
public java.util.Spliterator<Tuple2<K,V>> spliterator()
```
    Specified by:
    
    spliterator in interface Traversable<Tuple2<K,V>>
    
    Specified by:
    
    spliterator in interface Value<Tuple2<K,V>>
    
    Specified by:
    
    spliterator in interface java.lang.Iterable<Tuple2<K,V>>
  - tail
```
public HashMap<K,V> tail()
```
    Description copied from interface: Traversable
    
    Drops the first element of a non-empty Traversable.
    
    Specified by:
    
    tail in interface Map<K,V>
    
    Specified by:
    
    tail in interface Traversable<Tuple2<K,V>>
    
    Returns:
    
    A new instance of Traversable containing all elements except the first.
  - tailOption
```
public Option<HashMap<K,V>> tailOption()
```
    Description copied from interface: Traversable
    
    Drops the first element of a non-empty Traversable and returns an Option.
    
    Specified by:
    
    tailOption in interface Map<K,V>
    
    Specified by:
    
    tailOption in interface Traversable<Tuple2<K,V>>
    
    Returns:
    
    Some(traversable) or None if this is empty.
  - take
```
public HashMap<K,V> take(int n)
```
    Description copied from interface: Traversable
    
    Takes the first n elements of this or all elements, if this length < n.
    The result is equivalent to sublist(0, max(0, min(length(), n))) but does not throw if n < 0 or n > length().
    In the case of n < 0 the empty instance is returned, in the case of n > length() this is returned.
    
    Specified by:
    
    take in interface Map<K,V>
    
    Specified by:
    
    take in interface Traversable<Tuple2<K,V>>
    
    Parameters:
    
    n - The number of elements to take.
    
    Returns:
    
    A new instance consisting of the first n elements of this or all elements, if this has less than n elements.
  - takeRight
```
public HashMap<K,V> takeRight(int n)
```
    Description copied from interface: Traversable
    
    Takes the last n elements of this or all elements, if this length < n.
    The result is equivalent to sublist(max(0, min(length(), length() - n)), n), i.e. takeRight will not throw if n < 0 or n > length().
    In the case of n < 0 the empty instance is returned, in the case of n > length() this is returned.
    
    Specified by:
    
    takeRight in interface Map<K,V>
    
    Specified by:
    
    takeRight in interface Traversable<Tuple2<K,V>>
    
    Parameters:
    
    n - The number of elements to take.
    
    Returns:
    
    A new instance consisting of the last n elements of this or all elements, if this has less than n elements.
  - takeUntil
```
public HashMap<K,V> takeUntil(java.util.function.Predicate<? super Tuple2<K,V>> predicate)
```
    Description copied from interface: Traversable
    
    Takes elements until the predicate holds for the current element.
    Note: This is essentially the same as takeWhile(predicate.negate()). It is intended to be used with method references, which cannot be negated directly.
    
    Specified by:
    
    takeUntil in interface Map<K,V>
    
    Specified by:
    
    takeUntil in interface Traversable<Tuple2<K,V>>
    
    Parameters:
    
    predicate - A condition tested subsequently for this elements.
    
    Returns:
    
    a new instance consisting of all elements before the first one which does satisfy the given predicate.
  - takeWhile
```
public HashMap<K,V> takeWhile(java.util.function.Predicate<? super Tuple2<K,V>> predicate)
```
    Description copied from interface: Traversable
    
    Takes elements while the predicate holds for the current element.
    
    Specified by:
    
    takeWhile in interface Map<K,V>
    
    Specified by:
    
    takeWhile in interface Traversable<Tuple2<K,V>>
    
    Parameters:
    
    predicate - A condition tested subsequently for the contained elements.
    
    Returns:
    
    a new instance consisting of all elements before the first one which does not satisfy the given predicate.
  - toJavaMap
```
public java.util.HashMap<K,V> toJavaMap()
```
    Description copied from interface: Map
    
    Converts this Vavr Map to a java.util.Map while preserving characteristics like insertion order (LinkedHashMap) and sort order (SortedMap).
    
    Specified by:
    
    toJavaMap in interface Map<K,V>
    
    Returns:
    
    a new java.util.Map instance
  - values
```
public Stream<V> values()
```
    Description copied from interface: Map
    Returns a new Seq that contains the values of this Map.
```
 // = Seq("a", "b", "c")
 HashMap.of(1, "a", 2, "b", 3, "c").values()
 
```
    Specified by:
    
    values in interface Map<K,V>
    
    Returns:
    
    a new Seq
  - valuesIterator
```
public Iterator<V> valuesIterator()
```
    Description copied from interface: Map
    Returns the values in this map.
```
 // = Iterator.of("a", "b", "c")
 HashMap.of(1, "a", 2, "b", 3, "c").values()
 
```
    Specified by:
    
    valuesIterator in interface Map<K,V>
    
    Returns:
    
    a new Iterator
  - equals
```
public boolean equals(java.lang.Object other)
```
    Description copied from interface: Traversable
    In Vavr there are four basic classes of collections:
    - Seq (sequential elements)
    - Set (distinct elements)
    - Map (indexed elements)
    - Multimap (indexed collections)
    Two collection instances of these classes are equal if and only if both collections
    - belong to the same basic collection class (Seq, Set, Map or Multimap)
    - contain the same elements
    - have the same element order, if the collections are of type Seq
    Two Map/Multimap elements, resp. entries, (key1, value1) and (key2, value2) are equal, if the keys are equal and the values are equal.
    Notes:
    - No collection instance equals null, e.g. Queue(1) not equals null.
    - Nulls are allowed and handled as expected, e.g. List(null, 1) equals Stream(null, 1) and HashMap((null, 1)) equals LinkedHashMap((null, 1)).
    - The element order is taken into account for Seq only. E.g. List(null, 1) not equals Stream(1, null) and HashMap((null, 1), ("a", null)) equals LinkedHashMap(("a", null), (null, 1)). The reason is, that we do not know which implementations we compare when having two instances of type Map, Multimap or Set (see Liskov Substitution Principle).
    - Other collection classes are equal if their types are equal and their elements are equal (in iteration order).
    - Iterator equality is defined to be object reference equality.
    Specified by:
    
    equals in interface Traversable<Tuple2<K,V>>
    
    Specified by:
    
    equals in interface Value<Tuple2<K,V>>
    
    Overrides:
    
    equals in class java.lang.Object
    
    Parameters:
    
    other - an object, may be null
    
    Returns:
    
    true, if this collection equals the given object according to the rules described above, false otherwise.
  - hashCode
```
public int hashCode()
```
    Description copied from interface: Traversable
    Returns the hash code of this collection.
    We distinguish between two types of hashes, those for collections with predictable iteration order (like Seq) and those with arbitrary iteration order (like Set, Map and Multimap).
    In all cases the hash of an empty collection is defined to be 1.
    Collections with predictable iteration order are hashed as follows:
```
 int hash = 1;
 for (T t : this) { hash = hash * 31 + Objects.hashCode(t); }
 
```
    Collections with arbitrary iteration order are hashed in a way such that the hash of a fixed number of elements is independent of their iteration order.
```
 int hash = 1;
 for (T t : this) { hash += Objects.hashCode(t); }
 
```
    Please note that the particular hashing algorithms may change in a future version of Vavr.
    Generally, hash codes of collections aren't cached in Vavr (opposed to the size/length). Storing hash codes in order to reduce the time complexity would increase the memory footprint. Persistent collections are built upon tree structures, it allows us to implement efficient memory sharing. A drawback of tree structures is that they make it necessary to store collection attributes at each tree node (read: element).
    The computation of the hash code is linear in time, i.e. O(n). If the hash code of a collection is re-calculated often, e.g. when using a List as HashMap key, we might want to cache the hash code. This can be achieved by simply using a wrapper class, which is not included in Vavr but could be implemented like this:
```
 public final class Hashed<K> {

     private final K key;
     private final Lazy<Integer> hashCode;

     public Hashed(K key) {
         this.key = key;
         this.hashCode = Lazy.of(() -> Objects.hashCode(key));
     }

     public K key() {
         return key;
     }

     &#64;Override
     public boolean equals(Object o) {
         if (o == key) {
             return true;
         } else if (key != null && o instanceof Hashed) {
             final Hashed that = (Hashed) o;
             return key.equals(that.key);
         } else {
             return false;
         }
     }

     &#64;Override
     public int hashCode() {
         return hashCode.get();
     }

     &#64;Override
     public String toString() {
         return "Hashed(" + (key == null ? "null" : key.toString()) + ")";
     }
 }
 
```
    Specified by:
    
    hashCode in interface Traversable<Tuple2<K,V>>
    
    Specified by:
    
    hashCode in interface Value<Tuple2<K,V>>
    
    Overrides:
    
    hashCode in class java.lang.Object
    
    Returns:
    
    The hash code of this collection
  - stringPrefix
```
public java.lang.String stringPrefix()
```
    Description copied from interface: Value
    
    Returns the name of this Value type, which is used by toString().
    
    Specified by:
    
    stringPrefix in interface Value<Tuple2<K,V>>
    
    Returns:
    
    This type name.
  - toString
```
public java.lang.String toString()
```
    Description copied from interface: Value
    
    Clarifies that values have a proper toString() method implemented.
    See Object.toString().
    
    Specified by:
    
    toString in interface Value<Tuple2<K,V>>
    
    Overrides:
    
    toString in class java.lang.Object
    
    Returns:
    
    A String representation of this object

Class HashMap<K,V>

Method Summary

Methods inherited from class java.lang.Object

Methods inherited from interface io.vavr.collection.Map

Methods inherited from interface io.vavr.collection.Traversable

Methods inherited from interface io.vavr.Value

Methods inherited from interface io.vavr.Function1

Method Detail

collector

collector

collector

empty

narrow

of

ofAll

ofAll

ofAll

of

of

of

of

of

of

of

of

of

of

tabulate

fill

ofEntries

ofEntries

ofEntries

bimap

computeIfAbsent

computeIfPresent

containsKey

distinct

distinctBy

distinctBy

drop

dropRight

dropUntil

dropWhile

filter

filterNot

filter

filterNot

filterKeys

filterNotKeys

filterValues

filterNotValues

flatMap

get

getOrElse

groupBy

grouped

head

init

initOption

isAsync

isEmpty

isLazy

iterator

keySet

keysIterator

last

map

mapKeys

mapKeys

mapValues

merge

merge

orElse

orElse

partition

peek

put

put

put

put