org.infinispan.commons.util

Class InfinispanCollections

java.lang.Object

org.infinispan.commons.util.InfinispanCollections

public class InfinispanCollections
extends Object

Static helpers for Infinispan-specific collections

Since:

4.0

Author:

Manik Surtani

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	InfinispanCollections.EmptyList
static class	InfinispanCollections.EmptyMap
static class	InfinispanCollections.EmptySet
static interface	InfinispanCollections.Function<E,T> A function that converts a type into another one.
static interface	InfinispanCollections.MapMakerFunction<K,V,E> A function that converts an entry into a key/value pair for use in a map.

Constructor Summary

Constructors

Constructor and Description
InfinispanCollections()

Method Summary

Methods

Modifier and Type	Method and Description
static <T> boolean	containsAny(Collection<T> haystack, Collection<T> needle)
static <E> Set<E>	difference(Set<? extends E> s1, Set<? extends E> s2) Returns the elements that are present in s1 but which are not present in s2, without changing the contents of neither s1, nor s2.
static <T> List<T>	emptyList() Returns the empty list (immutable).
static <K,V> Map<K,V>	emptyMap() Returns the empty map (immutable).
static <T> Set<T>	emptySet() Returns the empty set (immutable).
static <K,V,E> Map<K,V>	transformCollectionToMap(Collection<? extends E> input, InfinispanCollections.MapMakerFunction<K,V,? super E> f) Given a collection, transforms the collection to a map given a InfinispanCollections.MapMakerFunction
static <K,V,E> Map<K,V>	transformMapValue(Map<K,E> input, InfinispanCollections.Function<E,V> f) Given a map of well known key/value types, it makes a shallow copy of it while at the same time transforming it's value type to a desired output type.

Constructor Detail

InfinispanCollections

public InfinispanCollections()

Method Detail

transformMapValue

public static <K,V,E> Map<K,V> transformMapValue(Map<K,E> input,
                                 InfinispanCollections.Function<E,V> f)

Given a map of well known key/value types, it makes a shallow copy of it while at the same time transforming it's value type to a desired output type. The transformation of the value type is done using a given a function.

Type Parameters:

K - input map's key type

V - desired output type of the map's value

E - input map's value type

Parameters:

input - contains the input key/value pair map

f - function instance to use to transform the value part of the map

Returns:

a shallow copy of the input Map with all its values transformed.

transformCollectionToMap

public static <K,V,E> Map<K,V> transformCollectionToMap(Collection<? extends E> input,
                                        InfinispanCollections.MapMakerFunction<K,V,? super E> f)

Given a collection, transforms the collection to a map given a InfinispanCollections.MapMakerFunction

Type Parameters:

K - output map's key type

V - output type of the map's value

E - input collection's entry type

Parameters:

input - contains a collection of type E

f - MapMakerFunction instance to use to transform the collection to a key/value pair

Returns:

a Map with keys and values generated from the input collection

difference

public static <E> Set<E> difference(Set<? extends E> s1,
                    Set<? extends E> s2)

Returns the elements that are present in s1 but which are not present in s2, without changing the contents of neither s1, nor s2.

Type Parameters:

E - type of objects in Set

Parameters:

s1 - first set

s2 - second set

Returns:

the elements in s1 that are not in s2

emptySet

public static final <T> Set<T> emptySet()

Returns the empty set (immutable). Contrary to Collections.emptySet(), the set returned returns a constant Iterator, rather than create a brand new one in each iterator call. This set is marshallable using Infinispan's Externalizer framework.

See Also:

InfinispanCollections.EMPTY_SET

emptyMap

public static final <K,V> Map<K,V> emptyMap()

Returns the empty map (immutable). Contrary to Collections.emptyMap(), the map returned returns a constant Iterator, rather than create a brand new one in each iterator call. This set is marshallable using Infinispan's Externalizer framework.

See Also:

InfinispanCollections.EMPTY_MAP

emptyList

public static final <T> List<T> emptyList()

Returns the empty list (immutable). Contrary to Collections.emptyList()}, the list returned returns a constant Iterator, rather than create a brand new one in each iterator call. This set is marshallable using Infinispan's Externalizer framework.

See Also:

InfinispanCollections.EMPTY_LIST

containsAny

public static final <T> boolean containsAny(Collection<T> haystack,
                      Collection<T> needle)