Package software.amazon.smithy.utils

Class MapUtils

java.lang.Object

software.amazon.smithy.utils.MapUtils

public final class MapUtils
extends java.lang.Object

Immutable Map utilities to polyfill Java 9+ features.

Method Summary

Modifier and Type	Method	Description
static <K,V> java.util.Map<K,V>	copyOf(java.util.Map<? extends K,? extends V> map)	Creates an immutable copy of the given map.
static <K,V> java.util.Map.Entry<K,V>	entry(K key, V value)	Creates an immutable Map.Entry from the given key and value.
static <K,V> java.util.Map<K,V>	of()	Returns an unmodifiable map containing zero mappings.
static <K,V> java.util.Map<K,V>	of(K k1, V v1)	Returns an unmodifiable map containing a single mapping.
static <K,V> java.util.Map<K,V>	of(K k1, V v1, K k2, V v2)	Returns an unmodifiable map containing two mappings.
static <K,V> java.util.Map<K,V>	of(K k1, V v1, K k2, V v2, K k3, V v3)	Returns an unmodifiable map containing three mappings.
static <K,V> java.util.Map<K,V>	of(K k1, V v1, K k2, V v2, K k3, V v3, K k4, V v4)	Returns an unmodifiable map containing four mappings.
static <K,V> java.util.Map<K,V>	of(K k1, V v1, K k2, V v2, K k3, V v3, K k4, V v4, K k5, V v5)	Returns an unmodifiable map containing five mappings.
static <K,V> java.util.Map<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)	Returns an unmodifiable map containing six mappings.
static <K,V> java.util.Map<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)	Returns an unmodifiable map containing seven mappings.
static <K,V> java.util.Map<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)	Returns an unmodifiable map containing eight mappings.
static <K,V> java.util.Map<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)	Returns an unmodifiable map containing nine mappings.
static <K,V> java.util.Map<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)	Returns an unmodifiable map containing ten mappings.
static <K,V> java.util.Map<K,V>	ofEntries(java.util.Map.Entry<? extends K,? extends V>... entries)	Creates an unmodifiable Map from an array of Map.Entry values.
static <K,V> java.util.Map<K,V>	orderedCopyOf(java.util.Map<? extends K,? extends V> map)	Creates an ordered immutable copy of the given map.
static <T,K,U> java.util.stream.Collector<T,?,java.util.Map<K,U>>	toUnmodifiableMap(java.util.function.Function<? super T,? extends K> keyMapper, java.util.function.Function<? super T,? extends U> valueMapper)	Creates a collector that collects into an unmodifiable Map.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Detail

copyOf

public static <K,V> java.util.Map<K,V> copyOf(java.util.Map<? extends K,? extends V> map)

Creates an immutable copy of the given map.

Type Parameters:

K - the Map's key type

V - the Map's value type

Parameters:

map - The map to make an immutable copy of

Returns:

An immutable Map copy

orderedCopyOf

public static <K,V> java.util.Map<K,V> orderedCopyOf(java.util.Map<? extends K,? extends V> map)

Creates an ordered immutable copy of the given map.

Type Parameters:

K - the Map's key type

V - the Map's value type

Parameters:

map - The map to make an immutable copy of

Returns:

An ordered immutable Map copy that maintains the order of the original.

of

public static <K,V> java.util.Map<K,V> of()

Returns an unmodifiable map containing zero mappings.

Type Parameters:

K - the Map's key type

V - the Map's value type

Returns:

an empty Map

of

public static <K,V> java.util.Map<K,V> of(K k1,
                                                      V v1)

Returns an unmodifiable map containing a single mapping.

Type Parameters:

K - the Map's key type

V - the Map's value type

Parameters:

k1 - the mapping's key

v1 - the mapping's value

Returns:

a Map containing the specified mapping

Throws:

java.lang.NullPointerException - if the key or the value is null

of

public static <K,V> java.util.Map<K,V> of(K k1,
                                                      V v1,
                                                      K k2,
                                                      V v2)

Returns an unmodifiable map containing two mappings.

Type Parameters:

K - the Map's key type

V - the Map's value type

Parameters:

k1 - the first mapping's key

v1 - the first mapping's value

k2 - the second mapping's key

v2 - the second mapping's value

Returns:

a Map containing the specified mappings

Throws:

java.lang.IllegalArgumentException - if the keys are duplicates

java.lang.NullPointerException - if any key or value is null

of

public static <K,V> java.util.Map<K,V> of(K k1,
                                                      V v1,
                                                      K k2,
                                                      V v2,
                                                      K k3,
                                                      V v3)

Returns an unmodifiable map containing three mappings.

Type Parameters:

K - the Map's key type

V - the Map's value type

Parameters:

k1 - the first mapping's key

v1 - the first mapping's value

k2 - the second mapping's key

v2 - the second mapping's value

k3 - the third mapping's key

v3 - the third mapping's value

Returns:

a Map containing the specified mappings

Throws:

java.lang.IllegalArgumentException - if there are any duplicate keys

java.lang.NullPointerException - if any key or value is null

of

public static <K,V> java.util.Map<K,V> of(K k1,
                                                      V v1,
                                                      K k2,
                                                      V v2,
                                                      K k3,
                                                      V v3,
                                                      K k4,
                                                      V v4)

Returns an unmodifiable map containing four mappings.

Type Parameters:

K - the Map's key type

V - the Map's value type

Parameters:

k1 - the first mapping's key

v1 - the first mapping's value

k2 - the second mapping's key

v2 - the second mapping's value

k3 - the third mapping's key

v3 - the third mapping's value

k4 - the fourth mapping's key

v4 - the fourth mapping's value

Returns:

a Map containing the specified mappings

Throws:

java.lang.IllegalArgumentException - if there are any duplicate keys

java.lang.NullPointerException - if any key or value is null

of

public static <K,V> java.util.Map<K,V> of(K k1,
                                                      V v1,
                                                      K k2,
                                                      V v2,
                                                      K k3,
                                                      V v3,
                                                      K k4,
                                                      V v4,
                                                      K k5,
                                                      V v5)

Returns an unmodifiable map containing five mappings.

Type Parameters:

K - the Map's key type

V - the Map's value type

Parameters:

k1 - the first mapping's key

v1 - the first mapping's value

k2 - the second mapping's key

v2 - the second mapping's value

k3 - the third mapping's key

v3 - the third mapping's value

k4 - the fourth mapping's key

v4 - the fourth mapping's value

k5 - the fifth mapping's key

v5 - the fifth mapping's value

Returns:

a Map containing the specified mappings

Throws:

java.lang.IllegalArgumentException - if there are any duplicate keys

java.lang.NullPointerException - if any key or value is null

of

public static <K,V> java.util.Map<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)

Returns an unmodifiable map containing six mappings.

Type Parameters:

K - the Map's key type

V - the Map's value type

Parameters:

k1 - the first mapping's key

v1 - the first mapping's value

k2 - the second mapping's key

v2 - the second mapping's value

k3 - the third mapping's key

v3 - the third mapping's value

k4 - the fourth mapping's key

v4 - the fourth mapping's value

k5 - the fifth mapping's key

v5 - the fifth mapping's value

k6 - the sixth mapping's key

v6 - the sixth mapping's value

Returns:

a Map containing the specified mappings

Throws:

java.lang.IllegalArgumentException - if there are any duplicate keys

java.lang.NullPointerException - if any key or value is null

of

public static <K,V> java.util.Map<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)

Returns an unmodifiable map containing seven mappings.

Type Parameters:

K - the Map's key type

V - the Map's value type

Parameters:

k1 - the first mapping's key

v1 - the first mapping's value

k2 - the second mapping's key

v2 - the second mapping's value

k3 - the third mapping's key

v3 - the third mapping's value

k4 - the fourth mapping's key

v4 - the fourth mapping's value

k5 - the fifth mapping's key

v5 - the fifth mapping's value

k6 - the sixth mapping's key

v6 - the sixth mapping's value

k7 - the seventh mapping's key

v7 - the seventh mapping's value

Returns:

a Map containing the specified mappings

Throws:

java.lang.IllegalArgumentException - if there are any duplicate keys

java.lang.NullPointerException - if any key or value is null

of

public static <K,V> java.util.Map<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)

Returns an unmodifiable map containing eight mappings.

Type Parameters:

K - the Map's key type

V - the Map's value type

Parameters:

k1 - the first mapping's key

v1 - the first mapping's value

k2 - the second mapping's key

v2 - the second mapping's value

k3 - the third mapping's key

v3 - the third mapping's value

k4 - the fourth mapping's key

v4 - the fourth mapping's value

k5 - the fifth mapping's key

v5 - the fifth mapping's value

k6 - the sixth mapping's key

v6 - the sixth mapping's value

k7 - the seventh mapping's key

v7 - the seventh mapping's value

k8 - the eighth mapping's key

v8 - the eighth mapping's value

Returns:

a Map containing the specified mappings

Throws:

java.lang.IllegalArgumentException - if there are any duplicate keys

java.lang.NullPointerException - if any key or value is null

of

public static <K,V> java.util.Map<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)

Returns an unmodifiable map containing nine mappings.

Type Parameters:

K - the Map's key type

V - the Map's value type

Parameters:

k1 - the first mapping's key

v1 - the first mapping's value

k2 - the second mapping's key

v2 - the second mapping's value

k3 - the third mapping's key

v3 - the third mapping's value

k4 - the fourth mapping's key

v4 - the fourth mapping's value

k5 - the fifth mapping's key

v5 - the fifth mapping's value

k6 - the sixth mapping's key

v6 - the sixth mapping's value

k7 - the seventh mapping's key

v7 - the seventh mapping's value

k8 - the eighth mapping's key

v8 - the eighth mapping's value

k9 - the ninth mapping's key

v9 - the ninth mapping's value

Returns:

a Map containing the specified mappings

Throws:

java.lang.IllegalArgumentException - if there are any duplicate keys

java.lang.NullPointerException - if any key or value is null

of

public static <K,V> java.util.Map<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)

Returns an unmodifiable map containing ten mappings.

Type Parameters:

K - the Map's key type

V - the Map's value type

Parameters:

k1 - the first mapping's key

v1 - the first mapping's value

k2 - the second mapping's key

v2 - the second mapping's value

k3 - the third mapping's key

v3 - the third mapping's value

k4 - the fourth mapping's key

v4 - the fourth mapping's value

k5 - the fifth mapping's key

v5 - the fifth mapping's value

k6 - the sixth mapping's key

v6 - the sixth mapping's value

k7 - the seventh mapping's key

v7 - the seventh mapping's value

k8 - the eighth mapping's key

v8 - the eighth mapping's value

k9 - the ninth mapping's key

v9 - the ninth mapping's value

k10 - the tenth mapping's key

v10 - the tenth mapping's value

Returns:

a Map containing the specified mappings

Throws:

java.lang.IllegalArgumentException - if there are any duplicate keys

java.lang.NullPointerException - if any key or value is null

entry

public static <K,V> java.util.Map.Entry<K,V> entry(K key,
                                                               V value)

Creates an immutable Map.Entry from the given key and value.

Type Parameters:

K - Key type.

V - Value type.

Parameters:

key - Key to set in the Map.Entry.

value - Value to set in the Map.Entry.

Returns:

Returns the created entry.

Throws:

java.lang.NullPointerException - if the key or value are null.

ofEntries

@SafeVarargs
public static <K,V> java.util.Map<K,V> ofEntries(java.util.Map.Entry<? extends K,? extends V>... entries)

Creates an unmodifiable Map from an array of Map.Entry values.

Type Parameters:

K - Map key type.

V - Map value type.

Parameters:

entries - Map entries to add to the created Map.

Returns:

Returns an unmodifiable map of the given entries.

toUnmodifiableMap

public static <T,K,U> java.util.stream.Collector<T,?,java.util.Map<K,U>> toUnmodifiableMap(java.util.function.Function<? super T,? extends K> keyMapper,
                                                                                                                         java.util.function.Function<? super T,? extends U> valueMapper)

Creates a collector that collects into an unmodifiable Map.

This is a polyfill equivalent of Java 10's Collectors#toUnmodifiableMap.

Type Parameters:

T - the type to retrieve keys and values from.

K - the Map's key type.

U - the Map's value type.

Parameters:

keyMapper - Function that retrieves the key.

valueMapper - Function that retrieves the value.

Returns:

a Collector that accumulates the entries into an unmodifiable Map.