graphql.util

Class FpKit

java.lang.Object

graphql.util.FpKit

public class FpKit
extends java.lang.Object

Constructor Summary

Constructors

Constructor and Description
FpKit()

Method Summary

Modifier and Type	Method and Description
static <T> java.util.List<T>	concat(java.util.List<T> l1, java.util.List<T> l2) Concatenates two lists into one
static <T> java.util.List<T>	concat(java.util.List<T> l, T t) Concatenates (appends) a single elements to an existing list
static <T> java.util.List<T>	filterList(java.util.Collection<T> list, java.util.function.Predicate<T> filter)
static <T> java.util.Set<T>	filterSet(java.util.Collection<T> input, java.util.function.Predicate<T> filter)
static <T> int	findIndex(java.util.List<T> list, java.util.function.Predicate<T> filter)
static <T> java.util.Optional<T>	findOne(java.util.Collection<T> list, java.util.function.Predicate<T> filter)
static <T> T	findOneOrNull(java.util.List<T> list, java.util.function.Predicate<T> filter)
static <T> java.util.concurrent.CompletableFuture<java.util.List<T>>	flatList(java.util.concurrent.CompletableFuture<java.util.List<java.util.List<T>>> cf)
static <T> java.util.List<T>	flatList(java.util.List<java.util.List<T>> listLists)
static <T> java.util.Map<java.lang.String,T>	getByName(java.util.List<T> namedObjects, java.util.function.Function<T,java.lang.String> nameFn)
static <T> java.util.Map<java.lang.String,T>	getByName(java.util.List<T> namedObjects, java.util.function.Function<T,java.lang.String> nameFn, java.util.function.BinaryOperator<T> mergeFunc)
static <T,NewKey> java.util.Map<NewKey,com.google.common.collect.ImmutableList<T>>	groupingBy(java.util.Collection<T> list, java.util.function.Function<T,NewKey> function)
static <T,NewKey> java.util.Map<NewKey,T>	groupingByUniqueKey(java.util.Collection<T> list, java.util.function.Function<T,NewKey> keyFunction)
static <T> java.util.function.Supplier<T>	interThreadMemoize(java.util.function.Supplier<T> delegate) This will memoize the Supplier across threads and make sure the Supplier is exactly called once.
static <T> java.util.function.Supplier<T>	intraThreadMemoize(java.util.function.Supplier<T> delegate) This will memoize the Supplier within the current thread's visibility, that is it does not use volatile reads but rather use a sentinel check and re-reads the delegate supplier value if the read has not stuck to this thread.
static boolean	isIterable(java.lang.Object result)
static <K,V,U> java.util.List<U>	mapEntries(java.util.Map<K,V> map, java.util.function.BiFunction<K,V,U> function)
static <T> java.util.function.BinaryOperator<T>	mergeFirst()
static <K,V> java.util.function.Function<K,java.util.List<V>>	newList() Used in simple Map.computeIfAbsent(Object, java.util.function.Function) cases
static <T> java.util.Collection<T>	toCollection(java.lang.Object iterableResult) Converts an object that should be an Iterable into a Collection efficiently, leaving it alone if it is already is one.
static <T> java.lang.Iterable<T>	toIterable(java.lang.Object iterableResult)
static <T> java.util.List<T>	toListOrSingletonList(java.lang.Object possibleIterable) Converts a value into a list if it's really a collection or array of things else it turns it into a singleton list containing that one value
static java.util.OptionalInt	toSize(java.lang.Object iterableResult)
static <T> java.util.List<java.util.List<T>>	transposeMatrix(java.util.List<? extends java.util.List<T>> matrix)
static <T> java.util.List<T>	valuesToList(java.util.Map<?,T> map)

Methods inherited from class java.lang.Object

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

Constructor Detail

FpKit

public FpKit()

Method Detail

getByName

public static <T> java.util.Map<java.lang.String,T> getByName(java.util.List<T> namedObjects,
                                                              java.util.function.Function<T,java.lang.String> nameFn,
                                                              java.util.function.BinaryOperator<T> mergeFunc)

groupingBy

public static <T,NewKey> java.util.Map<NewKey,com.google.common.collect.ImmutableList<T>> groupingBy(java.util.Collection<T> list,
                                                                                                     java.util.function.Function<T,NewKey> function)

groupingByUniqueKey

public static <T,NewKey> java.util.Map<NewKey,T> groupingByUniqueKey(java.util.Collection<T> list,
                                                                     java.util.function.Function<T,NewKey> keyFunction)

getByName

public static <T> java.util.Map<java.lang.String,T> getByName(java.util.List<T> namedObjects,
                                                              java.util.function.Function<T,java.lang.String> nameFn)

mergeFirst

public static <T> java.util.function.BinaryOperator<T> mergeFirst()

toCollection

public static <T> java.util.Collection<T> toCollection(java.lang.Object iterableResult)

Converts an object that should be an Iterable into a Collection efficiently, leaving it alone if it is already is one. Useful when you want to get the size of something

Type Parameters:

T - the type of thing

Parameters:

iterableResult - the result object

Returns:

an Iterable from that object

Throws:

java.lang.ClassCastException - if it's not an Iterable

toListOrSingletonList

public static <T> java.util.List<T> toListOrSingletonList(java.lang.Object possibleIterable)

Converts a value into a list if it's really a collection or array of things else it turns it into a singleton list containing that one value

Type Parameters:

T - for two

Parameters:

possibleIterable - the possible

Returns:

an list one way or another

isIterable

public static boolean isIterable(java.lang.Object result)

toIterable

public static <T> java.lang.Iterable<T> toIterable(java.lang.Object iterableResult)

toSize

public static java.util.OptionalInt toSize(java.lang.Object iterableResult)

concat

public static <T> java.util.List<T> concat(java.util.List<T> l,
                                           T t)

Concatenates (appends) a single elements to an existing list

Type Parameters:

T - the type of elements of the list

Parameters:

l - the list onto which to append the element

t - the element to append

Returns:

a new list composed of the first list elements and the new element

concat

public static <T> java.util.List<T> concat(java.util.List<T> l1,
                                           java.util.List<T> l2)

Concatenates two lists into one

Type Parameters:

T - the type of element of the lists

Parameters:

l1 - the first list to concatenate

l2 - the second list to concatenate

Returns:

a new list composed of the two concatenated lists elements

valuesToList

public static <T> java.util.List<T> valuesToList(java.util.Map<?,T> map)

mapEntries

public static <K,V,U> java.util.List<U> mapEntries(java.util.Map<K,V> map,
                                                   java.util.function.BiFunction<K,V,U> function)

transposeMatrix

public static <T> java.util.List<java.util.List<T>> transposeMatrix(java.util.List<? extends java.util.List<T>> matrix)

flatList

public static <T> java.util.concurrent.CompletableFuture<java.util.List<T>> flatList(java.util.concurrent.CompletableFuture<java.util.List<java.util.List<T>>> cf)

flatList

public static <T> java.util.List<T> flatList(java.util.List<java.util.List<T>> listLists)

findOne

public static <T> java.util.Optional<T> findOne(java.util.Collection<T> list,
                                                java.util.function.Predicate<T> filter)

findOneOrNull

public static <T> T findOneOrNull(java.util.List<T> list,
                                  java.util.function.Predicate<T> filter)

findIndex

public static <T> int findIndex(java.util.List<T> list,
                                java.util.function.Predicate<T> filter)

filterList

public static <T> java.util.List<T> filterList(java.util.Collection<T> list,
                                               java.util.function.Predicate<T> filter)

filterSet

public static <T> java.util.Set<T> filterSet(java.util.Collection<T> input,
                                             java.util.function.Predicate<T> filter)

newList

public static <K,V> java.util.function.Function<K,java.util.List<V>> newList()

Used in simple Map.computeIfAbsent(Object, java.util.function.Function) cases

Type Parameters:

K - for Key

V - for Value

Returns:

a function that allocates a list

intraThreadMemoize

public static <T> java.util.function.Supplier<T> intraThreadMemoize(java.util.function.Supplier<T> delegate)

This will memoize the Supplier within the current thread's visibility, that is it does not use volatile reads but rather use a sentinel check and re-reads the delegate supplier value if the read has not stuck to this thread. This means that it's possible that your delegate supplier MAY be called more than once across threads, but only once on the same thread.

Type Parameters:

T - for two

Parameters:

delegate - the supplier to delegate to

Returns:

a supplier that will memoize values in the context of the current thread

interThreadMemoize

public static <T> java.util.function.Supplier<T> interThreadMemoize(java.util.function.Supplier<T> delegate)

This will memoize the Supplier across threads and make sure the Supplier is exactly called once.

Use for potentially costly actions. Otherwise consider intraThreadMemoize(Supplier)

Type Parameters:

T - for two

Parameters:

delegate - the supplier to delegate to

Returns:

a supplier that will memoize values in the context of the all the threads