Package io.activej.common.collection

Class CollectionUtils

java.lang.Object

io.activej.common.collection.CollectionUtils

public final class CollectionUtils
extends Object

Constructor Summary

Constructors

Constructor	Description
CollectionUtils()

Method Summary

Modifier and Type	Method	Description
static <D> List<D>	concat(List<? extends D> list1, List<? extends D> list2)	Concatenates two lists into one
static <T> Set<T>	difference(Set<? extends T> a, Set<? extends T> b)	Returns a difference of two sets
static <T> T	first(Iterable<? extends T> iterable)
static <T> T	first(List<? extends T> list)
static <T> boolean	hasIntersection(Set<? extends T> a, Set<? extends T> b)
static <T> Set<T>	intersection(Set<? extends T> a, Set<? extends T> b)	Returns an intersection of two sets
static <T> T	last(Iterable<? extends T> iterable)
static <T> T	last(List<? extends T> list)
static <K, V> HashMap<K,V>	newHashMap(int initialSize)
static <T> HashSet<T>	newHashSet(int initialSize)
static <K, V> LinkedHashMap<K,V>	newLinkedHashMap(int initialSize)
static <T> LinkedHashSet<T>	newLinkedHashSet(int initialSize)
static <T> Set<T>	union(Set<? extends T> a, Set<? extends T> b)	Returns a union of two sets

Methods inherited from class java.lang.Object

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

Constructor Details

CollectionUtils

public CollectionUtils()

Method Details

concat

public static <D> List<D> concat(List<? extends D> list1,
 List<? extends D> list2)

Concatenates two lists into one

No guarantee on a mutability of a resulting list is made, so list should be considered unmodifiable

If any of concatenated lists is modified, the behaviour of a concatenated list is undefined

Throws:

NullPointerException - may be thrown if any list is null or contains null elements

difference

public static <T> Set<T> difference(Set<? extends T> a,
 Set<? extends T> b)

Returns a difference of two sets

No guarantee on a mutability of a resulting set is made, so set should be considered unmodifiable

If any of provided sets is modified, the behaviour of a resulting set is undefined

intersection

public static <T> Set<T> intersection(Set<? extends T> a,
 Set<? extends T> b)

Returns an intersection of two sets

No guarantee on a mutability of a resulting set is made, so set should be considered unmodifiable

If any of provided sets is modified, the behaviour of a resulting set is undefined

hasIntersection

public static <T> boolean hasIntersection(Set<? extends T> a,
 Set<? extends T> b)

union

public static <T> Set<T> union(Set<? extends T> a,
 Set<? extends T> b)

Returns a union of two sets

No guarantee on a mutability of a resulting set is made, so set should be considered unmodifiable

If any of provided sets is modified, the behaviour of a resulting set is undefined

first

public static <T> T first(List<? extends T> list)

first

public static <T> T first(Iterable<? extends T> iterable)

last

public static <T> T last(List<? extends T> list)

last

public static <T> T last(Iterable<? extends T> iterable)

newHashMap

public static <K,
V> HashMap<K,V> newHashMap(int initialSize)

newLinkedHashMap

public static <K,
V> LinkedHashMap<K,V> newLinkedHashMap(int initialSize)

newHashSet

public static <T> HashSet<T> newHashSet(int initialSize)

newLinkedHashSet

public static <T> LinkedHashSet<T> newLinkedHashSet(int initialSize)