software.amazon.awssdk.utils

Class CollectionUtils

java.lang.Object

software.amazon.awssdk.utils.CollectionUtils

public final class CollectionUtils
extends Object

Method Summary

Modifier and Type	Method and Description
static <T,U> Map<T,List<U>>	deepCopyMap(Map<T,? extends List<U>> map) Perform a deep copy of the provided map of lists.
static <T,U> Map<T,List<U>>	deepCopyMap(Map<T,? extends List<U>> map, Supplier<Map<T,List<U>>> mapConstructor) Perform a deep copy of the provided map of lists.
static <T,U> Map<T,List<U>>	deepUnmodifiableMap(Map<T,? extends List<U>> map) Perform a deep copy of the provided map of lists, and make the result unmodifiable.
static <T,U> Map<T,List<U>>	deepUnmodifiableMap(Map<T,? extends List<U>> map, Supplier<Map<T,List<U>>> mapConstructor) Perform a deep copy of the provided map of lists, and make the result unmodifiable.
static <T> T	firstIfPresent(List<T> list)
static boolean	isNullOrEmpty(Collection<?> collection)
static boolean	isNullOrEmpty(Map<?,?> map)
static <K,VInT,VOutT> Map<K,VOutT>	mapValues(Map<K,VInT> inputMap, Function<VInT,VOutT> mapper)
static <T> List<T>	mergeLists(List<T> list1, List<T> list2) Returns a new list containing the second list appended to the first list.
static <K,V> Collector<Map.Entry<K,V>,?,Map<K,V>>	toMap() Collect a stream of Map.Entry to a Map with the same key/value types
static <T,U> Map<T,List<U>>	unmodifiableMapOfLists(Map<T,List<U>> map)

Methods inherited from class java.lang.Object

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

Method Detail

isNullOrEmpty

public static boolean isNullOrEmpty(Collection<?> collection)

isNullOrEmpty

public static boolean isNullOrEmpty(Map<?,?> map)

mergeLists

public static <T> List<T> mergeLists(List<T> list1,
                                     List<T> list2)

Returns a new list containing the second list appended to the first list.

firstIfPresent

public static <T> T firstIfPresent(List<T> list)

Type Parameters:

T - Type of elements in the list.

Parameters:

list - List to get first element from.

Returns:

The first element in the list if it exists. If the list is null or empty this will return null.

deepCopyMap

public static <T,U> Map<T,List<U>> deepCopyMap(Map<T,? extends List<U>> map)

Perform a deep copy of the provided map of lists. This only performs a deep copy of the map and lists. Entries are not copied, so care should be taken to ensure that entries are immutable if preventing unwanted mutations of the elements is desired.

deepCopyMap

public static <T,U> Map<T,List<U>> deepCopyMap(Map<T,? extends List<U>> map,
                                               Supplier<Map<T,List<U>>> mapConstructor)

Perform a deep copy of the provided map of lists. This only performs a deep copy of the map and lists. Entries are not copied, so care should be taken to ensure that entries are immutable if preventing unwanted mutations of the elements is desired.

unmodifiableMapOfLists

public static <T,U> Map<T,List<U>> unmodifiableMapOfLists(Map<T,List<U>> map)

deepUnmodifiableMap

public static <T,U> Map<T,List<U>> deepUnmodifiableMap(Map<T,? extends List<U>> map)

Perform a deep copy of the provided map of lists, and make the result unmodifiable. This is equivalent to calling deepCopyMap(java.util.Map<T, ? extends java.util.List<U>>) followed by unmodifiableMapOfLists(java.util.Map<T, java.util.List<U>>).

deepUnmodifiableMap

public static <T,U> Map<T,List<U>> deepUnmodifiableMap(Map<T,? extends List<U>> map,
                                                       Supplier<Map<T,List<U>>> mapConstructor)

Perform a deep copy of the provided map of lists, and make the result unmodifiable. This is equivalent to calling deepCopyMap(java.util.Map<T, ? extends java.util.List<U>>) followed by unmodifiableMapOfLists(java.util.Map<T, java.util.List<U>>).

toMap

public static <K,V> Collector<Map.Entry<K,V>,?,Map<K,V>> toMap()

Collect a stream of Map.Entry to a Map with the same key/value types

Type Parameters:

K - the key type

V - the value type

Returns:

a map

mapValues

public static <K,VInT,VOutT> Map<K,VOutT> mapValues(Map<K,VInT> inputMap,
                                                    Function<VInT,VOutT> mapper)