org.axonframework.common

Class CollectionUtils

java.lang.Object

org.axonframework.common.CollectionUtils

public abstract class CollectionUtils
extends Object

Utility methods for operations on collections.

Since:

0.7

Author:

Allard Buijze

Method Summary

Modifier and Type	Method and Description
static <R> Collection<R>	asCollection(Object potentialCollection) Returns a Collection instance that contains the elements of the given potentialCollection.
static <T,C extends Collection<T>> C	intersect(Collection<? extends T> collection1, Collection<? extends T> collection2, Supplier<C> collectionBuilder) Returns a collection containing the elements that are in both given collections collection1 and collection2, using the given collectionBuilder to create an instance for the new collection.
static <S,T extends Collection<S>> T	merge(T collection1, T collection2, Supplier<T> factoryMethod) Merge two collections into a new collection instance.

Methods inherited from class java.lang.Object

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

Method Detail

merge

public static <S,T extends Collection<S>> T merge(T collection1,
                                                  T collection2,
                                                  Supplier<T> factoryMethod)

Merge two collections into a new collection instance. The new collection is created using the given factoryMethod.

If any of the two inputs collections is null or empty the other input collection is returned (even if that one is null as well).

Type Parameters:

S - the type of elements in the collections

T - the type of collection

Parameters:

collection1 - the first collection

collection2 - the second collection

factoryMethod - function to initialize the new collection

Returns:

a collection that combines both collections

asCollection

public static <R> Collection<R> asCollection(Object potentialCollection)

Returns a Collection instance that contains the elements of the given potentialCollection. If not a Collection-like structure, it will return a Collection with the given potentialCollection as the sole element.

The following structures are recognized and will have their elements placed inside a Collection:

• Stream
• Collection
• Array
• Spliterator
• Iterable

Type Parameters:

R - The type of instance contained in the resulting Collection

Parameters:

potentialCollection - The instance to collect all elements from

Returns:

A Collection of the elements contained in the given potentialCollection

intersect

public static <T,C extends Collection<T>> C intersect(Collection<? extends T> collection1,
                                                      Collection<? extends T> collection2,
                                                      Supplier<C> collectionBuilder)

Returns a collection containing the elements that are in both given collections collection1 and collection2, using the given collectionBuilder to create an instance for the new collection. The items are added to the resulting collection in the order as found in collection2.

Type Parameters:

T - The type of element contained in the resulting collection

C - The type of collection to return

Parameters:

collection1 - The first collection

collection2 - The second collection

collectionBuilder - The factory for the returned collection instance

Returns:

a collection containing the elements that were found in both given collections