Package com.gengoai.collection

Class Lists

java.lang.Object

com.gengoai.collection.Lists

public final class Lists
extends Object

Convenience methods for creating lists and manipulating collections resulting in lists.

Author:

David B. Bracewell

Method Summary

Modifier and Type	Method	Description
static <T> ArrayList<T>	arrayListOf(@NonNull T... elements)	Creates an array list of the supplied elements
static <T> ArrayList<T>	asArrayList(@NonNull Iterable<? extends T> iterable)	Creates an array list of the supplied elements
static <T> ArrayList<T>	asArrayList(@NonNull Iterator<? extends T> iterator)	Creates an array list of the supplied elements
static <T> ArrayList<T>	asArrayList(@NonNull Stream<? extends T> stream)	Creates an array list of the supplied elements
static <T> List<T>	asConcurrentList(@NonNull Iterable<? extends T> iterable)	Creates a copy on write array list of the supplied elements
static <T> List<T>	asConcurrentList(@NonNull Iterator<? extends T> iterator)	Creates a copy on write array list of the supplied elements
static <T> List<T>	asConcurrentList(@NonNull Stream<? extends T> stream)	Creates a copy on write array list of the supplied elements
static <T> LinkedList<T>	asLinkedList(@NonNull Iterable<? extends T> iterable)	Creates a linked list of the supplied elements
static <T> LinkedList<T>	asLinkedList(@NonNull Iterator<? extends T> iterator)	Creates a linked list of the supplied elements
static <T> List<T>	asLinkedList(Stream<? extends T> stream)	Creates a linked list of the supplied elements
static <T> Iterable<Tuple>	combinations(@NonNull List<T> list, int size)	Generates all combinations of the given size from the items in the list.
static <T> List<T>	concurrentListOf(@NonNull T... elements)	Creates a copy on write array list of the supplied elements
static <E> List<E>	difference(@NonNull Collection<? extends E> collection1, @NonNull Collection<? extends E> collection2)	Retains all items in collection1 that are not in collection2 and returns them as a list.
static <T> List<T>	ensureSize(@NonNull List<T> list, int desiredSize, T defaultValue)	Ensures that the size of the given list is at least the supplied desired size.
static <T> LinkedList<T>	linkedListOf(@NonNull T... elements)	Creates a linked list of the supplied elements
static <T> List<List<T>>	partition(@NonNull List<T> list, int partitionSize)	Partitions a list into multiple lists of partition size (last list may have a size less than partition size).
static <E> List<E>	sampleWithReplacement(@NonNull List<? extends E> list, int N)	Samples the given list for N items allowing replacement
static <I,O> List<O>	transform(@NonNull List<? extends I> list, @NonNull SerializableFunction<? super I,? extends O> converter)	Transforms the given list with the given function
static <E> List<E>	union(@NonNull Collection<? extends E> collection1, @NonNull Collection<? extends E> collection2)	Retains all items in collection1 and collection2 and returns them as a list.

Methods inherited from class java.lang.Object

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

Method Detail

arrayListOf

@SafeVarargs
public static <T> ArrayList<T> arrayListOf(@NonNull
                                           @NonNull T... elements)

Creates an array list of the supplied elements

Type Parameters:

T - the component type of the set

Parameters:

elements - the elements to add to the set

Returns:

the new array list containing the given elements

asArrayList

public static <T> ArrayList<T> asArrayList(@NonNull
                                           @NonNull Stream<? extends T> stream)

Creates an array list of the supplied elements

Type Parameters:

T - the component type of the set

Parameters:

stream - the elements to add to the set

Returns:

the new array list containing the given elements

asArrayList

public static <T> ArrayList<T> asArrayList(@NonNull
                                           @NonNull Iterator<? extends T> iterator)

Creates an array list of the supplied elements

Type Parameters:

T - the component type of the set

Parameters:

iterator - the elements to add to the set

Returns:

the new array list containing the given elements

asArrayList

public static <T> ArrayList<T> asArrayList(@NonNull
                                           @NonNull Iterable<? extends T> iterable)

Creates an array list of the supplied elements

Type Parameters:

T - the component type of the set

Parameters:

iterable - the elements to add to the set

Returns:

the new array list containing the given elements

asConcurrentList

public static <T> List<T> asConcurrentList(@NonNull
                                           @NonNull Stream<? extends T> stream)

Creates a copy on write array list of the supplied elements

Type Parameters:

T - the component type of the set

Parameters:

stream - the elements to add to the set

Returns:

the new copy on write array list containing the given elements

asConcurrentList

public static <T> List<T> asConcurrentList(@NonNull
                                           @NonNull Iterator<? extends T> iterator)

Creates a copy on write array list of the supplied elements

Type Parameters:

T - the component type of the set

Parameters:

iterator - the elements to add to the set

Returns:

the new copy on write array list containing the given elements

asConcurrentList

public static <T> List<T> asConcurrentList(@NonNull
                                           @NonNull Iterable<? extends T> iterable)

Creates a copy on write array list of the supplied elements

Type Parameters:

T - the component type of the set

Parameters:

iterable - the elements to add to the set

Returns:

the new copy on write array list containing the given elements

asLinkedList

public static <T> List<T> asLinkedList(Stream<? extends T> stream)

Creates a linked list of the supplied elements

Type Parameters:

T - the component type of the set

Parameters:

stream - the elements to add to the set

Returns:

the new linked list containing the given elements

asLinkedList

public static <T> LinkedList<T> asLinkedList(@NonNull
                                             @NonNull Iterator<? extends T> iterator)

Creates a linked list of the supplied elements

Type Parameters:

T - the component type of the set

Parameters:

iterator - the elements to add to the set

Returns:

the new linked list containing the given elements

asLinkedList

public static <T> LinkedList<T> asLinkedList(@NonNull
                                             @NonNull Iterable<? extends T> iterable)

Creates a linked list of the supplied elements

Type Parameters:

T - the component type of the set

Parameters:

iterable - the elements to add to the set

Returns:

the new linked list containing the given elements

combinations

public static <T> Iterable<Tuple> combinations(@NonNull
                                               @NonNull List<T> list,
                                               int size)

Generates all combinations of the given size from the items in the list. For example, given the list [1, 2, 3] and size 2 we would generate the following combinations: [ [1,2], [1,3], [2,3] ]

Type Parameters:

T - the type parameter

Parameters:

list - the list of items

size - the number of items in the combination.

Returns:

the iterable

concurrentListOf

@SafeVarargs
public static <T> List<T> concurrentListOf(@NonNull
                                           @NonNull T... elements)

Creates a copy on write array list of the supplied elements

Type Parameters:

T - the component type of the set

Parameters:

elements - the elements to add to the set

Returns:

the new copy on write array list containing the given elements

difference

public static <E> List<E> difference(@NonNull
                                     @NonNull Collection<? extends E> collection1,
                                     @NonNull
                                     @NonNull Collection<? extends E> collection2)

Retains all items in collection1 that are not in collection2 and returns them as a list.

Type Parameters:

E - the component type of the collections

Parameters:

collection1 - the first collection of items

collection2 - the second collection of items

Returns:

A list of the collection1 - collection2

ensureSize

public static <T> List<T> ensureSize(@NonNull
                                     @NonNull List<T> list,
                                     int desiredSize,
                                     T defaultValue)

Ensures that the size of the given list is at least the supplied desired size. If the list size is smaller, it will add the given default value to the end of the list until list.size() >= desiredSize

Type Parameters:

T - the component type of the list

Parameters:

list - the list whose size is being checked

desiredSize - the desired size of the list

defaultValue - the default value to add to the list to reach the desired size

Returns:

the list passed in with size greater than or equal to the desired size

linkedListOf

@SafeVarargs
public static <T> LinkedList<T> linkedListOf(@NonNull
                                             @NonNull T... elements)

Creates a linked list of the supplied elements

Type Parameters:

T - the component type of the set

Parameters:

elements - the elements to add to the set

Returns:

the new linked list containing the given elements

partition

public static <T> List<List<T>> partition(@NonNull
                                          @NonNull List<T> list,
                                          int partitionSize)

Partitions a list into multiple lists of partition size (last list may have a size less than partition size). This method uses subList which means that each partition is a view into the underlying list.

Type Parameters:

T - the list component type

Parameters:

list - the list to partition

partitionSize - the partition size

Returns:

A list of partitioned lists

sampleWithReplacement

public static <E> List<E> sampleWithReplacement(@NonNull
                                                @NonNull List<? extends E> list,
                                                int N)

Samples the given list for N items allowing replacement

Type Parameters:

E - the list type parameter

Parameters:

list - the list of elements to sample

N - the number of elements to sample

Returns:

the list of sampled elements

transform

public static <I,O> List<O> transform(@NonNull
                                            @NonNull List<? extends I> list,
                                            @NonNull
                                            @NonNull SerializableFunction<? super I,? extends O> converter)

Transforms the given list with the given function

Type Parameters:

I - the input list type parameter

O - the transformed list type parameter

Parameters:

list - the input list

converter - the function to convert the input elements to the output elements

Returns:

the transformed list (lazy transformation)

union

public static <E> List<E> union(@NonNull
                                @NonNull Collection<? extends E> collection1,
                                @NonNull
                                @NonNull Collection<? extends E> collection2)

Retains all items in collection1 and collection2 and returns them as a list.

Type Parameters:

E - the component type of the collections

Parameters:

collection1 - the first collection of items

collection2 - the second collection of items

Returns:

A list of the collection1 + collection2