com.edorasware.commons.core.util.collect

Class CollectionUtils

java.lang.Object

com.edorasware.commons.core.util.collect.CollectionUtils

public final class CollectionUtils
extends Object

Provides utility methods related to dealing with Collections.

Method Summary

Modifier and Type	Method and Description
static <T,U> com.google.common.collect.ImmutableCollection<U>	filterAndTransform(Collection<T> elements, com.google.common.base.Function<T,com.google.common.base.Optional<U>> function) Filters and transforms the matching elements.
static <T> com.google.common.collect.ImmutableList<T>	remove(List<? extends T> source, List<? extends T> toRemove) Removes the given elements from the given list.
static <T> com.google.common.collect.ImmutableSet<T>	remove(Set<? extends T> source, Set<? extends T> toRemove) Removes the given elements from the given set.
static <T> Pair<com.google.common.collect.ImmutableCollection<T>,com.google.common.collect.ImmutableCollection<T>>	separate(Collection<T> elements, com.google.common.base.Predicate<? super T> predicate) Separates the elements of the given collection by the given predicate into two collections.
static <T> com.google.common.collect.ImmutableList<T>	tailSubList(Collection<T> collection, int n) Returns the n last elements of the given collection.
static <E> com.google.common.collect.ImmutableSet<E>	toSetKeepFirst(Collection<E> elements, com.google.common.base.Equivalence<E> equivalence) Returns a set of the given elements where element equality is defined by the given Equivalence instance.
static <E> com.google.common.collect.ImmutableSet<E>	toSetKeepLast(Collection<E> elements, com.google.common.base.Equivalence<E> equivalence) Returns a set of the given elements where element equality is defined by the given Equivalence instance.
static <T> List<T>	toTypedList(List list) 'Converts' the given list to a typed list.
static <K,V> Map<K,V>	toTypedMap(Map map) 'Converts' the given map to a typed map.
static <T> Set<T>	toTypedSet(Set set) 'Converts' the given set to a typed set.
static <V,W> List<Object>	transformListRecursively(List<? extends Object> list, com.google.common.base.Function<V,W> atomicValueFunction) Recursively transforms the values of the given list by applying the given function.
static <K,V,W> Map<K,Object>	transformMapRecursively(Map<K,? extends Object> map, com.google.common.base.Function<V,W> atomicValueFunction) Recursively transforms the values of the given map by applying the given function.
static <V,W> Set<Object>	transformSetRecursively(Set<? extends Object> set, com.google.common.base.Function<V,W> atomicValueFunction) Recursively transforms the values of the given set by applying the given function.
static <T,V> Map<T,V>	unmodifiableDetachedMap(Map<T,V> map) Converts the map to an immutable map.

Methods inherited from class java.lang.Object

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

Method Detail

transformListRecursively

public static <V,W> List<Object> transformListRecursively(List<? extends Object> list,
                                                          com.google.common.base.Function<V,W> atomicValueFunction)

Recursively transforms the values of the given list by applying the given function. Recursion occurs if and only if a list value is of type List, Set, or Map, all other value types are considered 'atomic' and will have the given transformation function applied.

Type Parameters:

V - the type of the atomic values contained in this list, top-level or nested

W - the type of the result values

Parameters:

list - the list whose values to transform

atomicValueFunction - the transformation function to apply on the list values

Returns:

a new list with the transformed values

transformSetRecursively

public static <V,W> Set<Object> transformSetRecursively(Set<? extends Object> set,
                                                        com.google.common.base.Function<V,W> atomicValueFunction)

Recursively transforms the values of the given set by applying the given function. Recursion occurs if and only if a set value is of type List, Set, or Map, all other value types are considered 'atomic' and will have the given transformation function applied.

Type Parameters:

V - the type of the atomic values contained in this set, top-level or nested

W - the type of the result values

Parameters:

set - the set whose values to transform

atomicValueFunction - the transformation function to apply on the set values

Returns:

a new set with the transformed values

transformMapRecursively

public static <K,V,W> Map<K,Object> transformMapRecursively(Map<K,? extends Object> map,
                                                            com.google.common.base.Function<V,W> atomicValueFunction)

Recursively transforms the values of the given map by applying the given function. Recursion occurs if and only if a map value is of type List, Set, or Map, all other value types are considered 'atomic' and will have the given transformation function applied.

Type Parameters:

K - the type of the key

V - the type of the atomic values contained in this map, top-level or nested

W - the type of the result values

Parameters:

map - the map whose values to transform

atomicValueFunction - the transformation function to apply on the map values

Returns:

a new map with the transformed values

tailSubList

public static <T> com.google.common.collect.ImmutableList<T> tailSubList(Collection<T> collection,
                                                                         int n)

Returns the n last elements of the given collection. The order of the elements returned is the same as in the original collection.

Type Parameters:

T - the type of the list

Parameters:

collection - the collection from which to return the n last elements

n - the number of elements to return

Returns:

the n last elements of the given collection

toSetKeepFirst

public static <E> com.google.common.collect.ImmutableSet<E> toSetKeepFirst(Collection<E> elements,
                                                                           com.google.common.base.Equivalence<E> equivalence)

Returns a set of the given elements where element equality is defined by the given Equivalence instance. In case of equality of n elements, the first element of the n elements is added to the Set.

Type Parameters:

E - the type of the set

Parameters:

elements - the elements to put in a Set

equivalence - the Equivalence that defines equality of two elements

Returns:

the set of elements

toSetKeepLast

public static <E> com.google.common.collect.ImmutableSet<E> toSetKeepLast(Collection<E> elements,
                                                                          com.google.common.base.Equivalence<E> equivalence)

Returns a set of the given elements where element equality is defined by the given Equivalence instance. In case of equality of n elements, the last element of the n elements is added to the Set.

Type Parameters:

E - the type of the set

Parameters:

elements - the elements to put in a Set

equivalence - the Equivalence that defines equality of two elements

Returns:

the set of elements

separate

public static <T> Pair<com.google.common.collect.ImmutableCollection<T>,com.google.common.collect.ImmutableCollection<T>> separate(Collection<T> elements,
                                                                                                                                   com.google.common.base.Predicate<? super T> predicate)

Separates the elements of the given collection by the given predicate into two collections.

Type Parameters:

T - the type of the collection

Parameters:

elements - the elements to separate

predicate - the predicate by which to separate the elements

Returns:

a pair with the first element containing the matching elements and the second element containing the non-matching elements

filterAndTransform

public static <T,U> com.google.common.collect.ImmutableCollection<U> filterAndTransform(Collection<T> elements,
                                                                                        com.google.common.base.Function<T,com.google.common.base.Optional<U>> function)

Filters and transforms the matching elements.

Type Parameters:

T - the type of the elements

U - the type of the returned and transformed collection

Parameters:

elements - the elements to filter and transform

function - the transformation to apply, returns Optional.absent() for non-matching elements

Returns:

the filtered and transformed elements

unmodifiableDetachedMap

public static <T,V> Map<T,V> unmodifiableDetachedMap(Map<T,V> map)

Converts the map to an immutable map. The map must not contain null values.

Type Parameters:

T - the type of the key

V - the type of the value

Parameters:

map - the map, can be null

Returns:

the immutable map

remove

public static <T> com.google.common.collect.ImmutableList<T> remove(List<? extends T> source,
                                                                    List<? extends T> toRemove)

Removes the given elements from the given list.

Type Parameters:

T - the type of the list

Parameters:

source - the list to remove from

toRemove - the elements to remove

Returns:

the resulting list

remove

public static <T> com.google.common.collect.ImmutableSet<T> remove(Set<? extends T> source,
                                                                   Set<? extends T> toRemove)

Removes the given elements from the given set.

Type Parameters:

T - the type of the set

Parameters:

source - the set to remove from

toRemove - the elements to remove

Returns:

the resulting set

toTypedList

public static <T> List<T> toTypedList(List list)

'Converts' the given list to a typed list. Note that this is an unsafe operation since the compiler is tricked into thinking that the given list contains elements of the types given by the list which will store the result of calling this method. This method is only offered to avoid compiler warnings in the calling code.

Type Parameters:

T - the type of the list

Parameters:

list - the list to 'convert'

Returns:

the list with types as defined by the field that will store the resulting typed list

toTypedSet

public static <T> Set<T> toTypedSet(Set set)

'Converts' the given set to a typed set. Note that this is an unsafe operation since the compiler is tricked into thinking that the given set contains elements of the types given by the set which will store the result of calling this method. This method is only offered to avoid compiler warnings in the calling code.

Type Parameters:

T - the type of the set

Parameters:

set - the set to 'convert'

Returns:

the set with types as defined by the field that will store the resulting typed map

toTypedMap

public static <K,V> Map<K,V> toTypedMap(Map map)

'Converts' the given map to a typed map. Note that this is an unsafe operation since the compiler is tricked into thinking that the given map contains keys and values of the types given by the map which will store the result of calling this method. This method is only offered to avoid compiler warnings in the calling code.

Type Parameters:

K - the type of the key

V - the type of the value

Parameters:

map - the map to 'convert'

Returns:

the map with types as defined by the field that will store the resulting typed map