com.helger.commons.collection.impl

Interface ICommonsCollection<ELEMENTTYPE>

Type Parameters:

ELEMENTTYPE - The data type stored in the collection

All Superinterfaces:

Collection<ELEMENTTYPE>, ICommonsIterable<ELEMENTTYPE>, IHasSize, Iterable<ELEMENTTYPE>, Serializable

All Known Subinterfaces:

ICommonsList<ELEMENTTYPE>, ICommonsNavigableSet<ELEMENTTYPE>, ICommonsOrderedSet<ELEMENTTYPE>, ICommonsSet<ELEMENTTYPE>, ICommonsSortedSet<ELEMENTTYPE>, IErrorList

All Known Implementing Classes:

CommonsArrayList, CommonsCopyOnWriteArrayList, CommonsCopyOnWriteArraySet, CommonsHashSet, CommonsLinkedHashSet, CommonsLinkedList, CommonsTreeSet, CommonsVector, ErrorList, LRUSet, NonBlockingStack, URLParameterList

public interface ICommonsCollection<ELEMENTTYPE>
extends Collection<ELEMENTTYPE>, ICommonsIterable<ELEMENTTYPE>, IHasSize

Case collection interface for my extended collection classes.

Author:

Philip Helger

Method Summary

Modifier and Type	Method and Description
default EChange	addAll(ELEMENTTYPE... aElements) Add an array of elements to this collection.
default EChange	addAll(ELEMENTTYPE[] aElements, Predicate<? super ELEMENTTYPE> aFilter) Add all matching elements of an array this collection.
default EChange	addAll(Enumeration<? extends ELEMENTTYPE> aEnum) Add all elements of the passed enumeration to this collection.
default EChange	addAll(Enumeration<? extends ELEMENTTYPE> aEnum, Predicate<? super ELEMENTTYPE> aFilter) Add all elements of the passed enumeration to this collection.
default EChange	addAll(Iterable<? extends ELEMENTTYPE> aElements) Add all elements of the passed iterable to this collection.
default EChange	addAll(Iterable<? extends ELEMENTTYPE> aElements, Predicate<? super ELEMENTTYPE> aFilter) Add all elements of the passed iterable to this collection.
default EChange	addAll(Iterator<? extends ELEMENTTYPE> aIter) Add all elements of the passed iterator to this collection.
default EChange	addAll(Iterator<? extends ELEMENTTYPE> aIter, Predicate<? super ELEMENTTYPE> aFilter) Add all elements of the passed iterator to this collection.
default <SRCTYPE> EChange	addAllMapped(Iterable<? extends SRCTYPE> aElements, Function<? super SRCTYPE,? extends ELEMENTTYPE> aMapper) Add all passed elements after performing a mapping using the provided function.
default <SRCTYPE> EChange	addAllMapped(Iterable<? extends SRCTYPE> aElements, Function<? super SRCTYPE,? extends ELEMENTTYPE> aMapper, Predicate<? super ELEMENTTYPE> aFilter) Add all passed elements matching the provided filter after performing a mapping using the provided function.
default <SRCTYPE> EChange	addAllMapped(Iterable<? extends SRCTYPE> aElements, Predicate<? super SRCTYPE> aFilter, Function<? super SRCTYPE,? extends ELEMENTTYPE> aMapper) Add all passed elements matching the provided filter after performing a mapping using the provided function.
default <SRCTYPE> EChange	addAllMapped(SRCTYPE[] aElements, Function<? super SRCTYPE,? extends ELEMENTTYPE> aMapper) Add all passed elements after performing a mapping using the provided function.
default <SRCTYPE> EChange	addAllMapped(SRCTYPE[] aElements, Function<? super SRCTYPE,? extends ELEMENTTYPE> aMapper, Predicate<? super ELEMENTTYPE> aFilter) Add all passed elements matching the provided filter after performing a mapping using the provided function.
default <SRCTYPE> EChange	addAllMapped(SRCTYPE[] aElements, Predicate<? super SRCTYPE> aFilter, Function<? super SRCTYPE,? extends ELEMENTTYPE> aMapper) Add all passed elements matching the provided filter after performing a mapping using the provided function.
default EChange	addIf(ELEMENTTYPE aElement, Predicate<? super ELEMENTTYPE> aFilter) Add the passed element to this collection if passed predicate is fulfilled
default EChange	addIfNotNull(ELEMENTTYPE aElement) Add the passed element to this collection if it is non-null.
default EChange	addObject(ELEMENTTYPE aElement) add the provided element to the collection using Collection.add(Object) but returning a more structured return value.
default Collection<ELEMENTTYPE>	getAsUnmodifiable()
default ELEMENTTYPE	getAtIndex(int nIndex) Get the element at the specified index or return null upon invalid index.
default ELEMENTTYPE	getAtIndex(int nIndex, ELEMENTTYPE aDefault) Get the element at the specified index or return the provided default value upon invalid index.
default ELEMENTTYPE	getAtIndex(Predicate<? super ELEMENTTYPE> aFilter, int nIndex) Get the element at the specified index counting only elements matching the specified filter.
default ELEMENTTYPE	getAtIndex(Predicate<? super ELEMENTTYPE> aFilter, int nIndex, ELEMENTTYPE aDefault) Get the element at the specified index counting only elements matching the specified filter or return the provided default value upon invalid index.
default <DSTTYPE> DSTTYPE	getAtIndexMapped(int nIndex, Function<? super ELEMENTTYPE,? extends DSTTYPE> aMapper) Get the element at the specified index or return null upon invalid index.
default <DSTTYPE> DSTTYPE	getAtIndexMapped(int nIndex, Function<? super ELEMENTTYPE,? extends DSTTYPE> aMapper, DSTTYPE aDefault) Get the element at the specified index or return the provided default value upon invalid index.
default <DSTTYPE> DSTTYPE	getAtIndexMapped(Predicate<? super ELEMENTTYPE> aFilter, int nIndex, Function<? super ELEMENTTYPE,? extends DSTTYPE> aMapper) Get the element at the specified index, counting only elements matching the provided filter and map the resulting element using the provided mapper.
default <DSTTYPE> DSTTYPE	getAtIndexMapped(Predicate<? super ELEMENTTYPE> aFilter, int nIndex, Function<? super ELEMENTTYPE,? extends DSTTYPE> aMapper, DSTTYPE aDefault) Get the element at the specified index, counting only elements matching the provided filter and map the resulting element using the provided mapper.
default ICommonsList<ELEMENTTYPE>	getCopyAsList()
default int	getCount(Predicate<? super ELEMENTTYPE> aFilter) Count the number of elements matching the provided filter.
default ICommonsList<ELEMENTTYPE>	getSorted(Comparator<? super ELEMENTTYPE> aComparator) Return a sorted version of this collection.
default IIterableIterator<ELEMENTTYPE>	iterator2()
default EChange	removeAll() Remove all elements from this collection.
default EChange	removeObject(ELEMENTTYPE aElement) Remove the provided element from the collection using Collection.remove(Object) but returning a more structured return value.
default EChange	set(ELEMENTTYPE aValue) Clear all elements and add only the passed value.
default EChange	setAll(ELEMENTTYPE... aValues) Clear all elements and add all provided values.
default EChange	setAll(Iterable<? extends ELEMENTTYPE> aValues) Clear all elements and add all provided values.

Methods inherited from interface java.util.Collection

add, addAll, clear, contains, containsAll, equals, hashCode, isEmpty, iterator, parallelStream, remove, removeAll, removeIf, retainAll, size, spliterator, stream, toArray, toArray

Methods inherited from interface com.helger.commons.collection.impl.ICommonsIterable

containsAny, containsNone, containsOnly, findAll, findAllInstanceOf, findAllMapped, findAllMapped, findAllMapped, findFirst, findFirst, findFirstMapped, findFirstMapped, forEach, forEachBreakable, forEachByIndex, getCount

Methods inherited from interface java.lang.Iterable

forEach

Methods inherited from interface com.helger.commons.lang.IHasSize

isEmpty, isNotEmpty, size

Method Detail

getCopyAsList

@Nonnull
 @ReturnsMutableCopy
default ICommonsList<ELEMENTTYPE> getCopyAsList()

getCount

@Nonnegative
default int getCount(@Nullable
                                   Predicate<? super ELEMENTTYPE> aFilter)

Count the number of elements matching the provided filter.

Specified by:

getCount in interface ICommonsIterable<ELEMENTTYPE>

Parameters:

aFilter - The filter to be applied. May be null.

Returns:

The number of elements matching the provided filter or the total number of elements if no filter is provided. Always ≥ 0.

getAtIndex

@Nullable
default ELEMENTTYPE getAtIndex(@Nonnegative
                                          int nIndex)

Get the element at the specified index or return null upon invalid index.

Parameters:

nIndex - The index to access. Should be ≥ 0.

Returns:

null if the element cannot be accessed.

See Also:

getAtIndex(int, Object)

getAtIndex

@Nullable
default ELEMENTTYPE getAtIndex(@Nonnegative
                                          int nIndex,
                                          @Nullable
                                          ELEMENTTYPE aDefault)

Get the element at the specified index or return the provided default value upon invalid index.

Parameters:

nIndex - The index to access. Should be ≥ 0.

aDefault - The value to be returned, if the index is out of bounds. May be null.

Returns:

The default parameter if the element cannot be accessed

See Also:

getAtIndex(int)

getAtIndex

@Nullable
default ELEMENTTYPE getAtIndex(@Nullable
                                          Predicate<? super ELEMENTTYPE> aFilter,
                                          @Nonnegative
                                          int nIndex)

Get the element at the specified index counting only elements matching the specified filter. If no filter is provided this call is identical to getAtIndex(int).

Parameters:

aFilter - The filter to be applied. May be null.

nIndex - The index to be retrieved. Should be ≥ 0.

Returns:

null if no matching element could be accessed.

See Also:

getAtIndex(Predicate, int, Object)

getAtIndex

@Nullable
default ELEMENTTYPE getAtIndex(@Nullable
                                          Predicate<? super ELEMENTTYPE> aFilter,
                                          @Nonnegative
                                          int nIndex,
                                          @Nullable
                                          ELEMENTTYPE aDefault)

Get the element at the specified index counting only elements matching the specified filter or return the provided default value upon invalid index. If no filter is provided this call is identical to getAtIndex(int, Object).

Parameters:

aFilter - The filter to be applied. May be null.

nIndex - The index to access. Should be ≥ 0.

aDefault - The value to be returned, if the index is out of bounds. May be null.

Returns:

The default parameter if the element cannot be accessed

See Also:

getAtIndex(Predicate,int)

getAtIndexMapped

@Nullable
default <DSTTYPE> DSTTYPE getAtIndexMapped(@Nonnegative
                                                      int nIndex,
                                                      @Nonnull
                                                      Function<? super ELEMENTTYPE,? extends DSTTYPE> aMapper)

Get the element at the specified index or return null upon invalid index.

Type Parameters:

DSTTYPE - The destination type to be mapped to

Parameters:

nIndex - The index to access. Should be ≥ 0.

aMapper - The mapping function to be executed for the matching element. May not be null.

Returns:

null if the element cannot be accessed.

See Also:

getAtIndexMapped(int,Function, Object)

getAtIndexMapped

@Nullable
default <DSTTYPE> DSTTYPE getAtIndexMapped(@Nonnegative
                                                      int nIndex,
                                                      @Nonnull
                                                      Function<? super ELEMENTTYPE,? extends DSTTYPE> aMapper,
                                                      @Nullable
                                                      DSTTYPE aDefault)

Get the element at the specified index or return the provided default value upon invalid index.

Type Parameters:

DSTTYPE - The destination type to be mapped to

Parameters:

nIndex - The index to access. Should be ≥ 0.

aMapper - The mapping function to be executed for the matching element. May not be null.

aDefault - The value to be returned, if the index is out of bounds. May be null.

Returns:

The default parameter if the element cannot be accessed

See Also:

getAtIndexMapped(int, Function)

getAtIndexMapped

@Nullable
default <DSTTYPE> DSTTYPE getAtIndexMapped(@Nonnull
                                                      Predicate<? super ELEMENTTYPE> aFilter,
                                                      @Nonnegative
                                                      int nIndex,
                                                      @Nonnull
                                                      Function<? super ELEMENTTYPE,? extends DSTTYPE> aMapper)

Get the element at the specified index, counting only elements matching the provided filter and map the resulting element using the provided mapper.

Type Parameters:

DSTTYPE - The destination type to be mapped to

Parameters:

aFilter - The filter to be applied. May be null.

nIndex - The index to be accessed. Should be ≥ 0.

aMapper - The mapping function to be executed for the matching element. May not be null.

Returns:

null if no such element at the specified index was found.

See Also:

getAtIndexMapped(Predicate, int, Function, Object)

getAtIndexMapped

@Nullable
default <DSTTYPE> DSTTYPE getAtIndexMapped(@Nonnull
                                                      Predicate<? super ELEMENTTYPE> aFilter,
                                                      @Nonnegative
                                                      int nIndex,
                                                      @Nonnull
                                                      Function<? super ELEMENTTYPE,? extends DSTTYPE> aMapper,
                                                      @Nullable
                                                      DSTTYPE aDefault)

Get the element at the specified index, counting only elements matching the provided filter and map the resulting element using the provided mapper.

Type Parameters:

DSTTYPE - The destination type to be mapped to

Parameters:

aFilter - The filter to be applied. May be null.

nIndex - The index to be accessed. Should be ≥ 0.

aMapper - The mapping function to be executed for the matching element. May not be null.

aDefault - The default value to be returned if no matching element could be found.

Returns:

The provided default value if no such element at the specified index was found.

See Also:

getAtIndexMapped(Predicate, int, Function)

getSorted

@Nonnull
default ICommonsList<ELEMENTTYPE> getSorted(@Nonnull
                                                      Comparator<? super ELEMENTTYPE> aComparator)

Return a sorted version of this collection. The default implementation returns a copy of this collection as a CommonsArrayList and sort this list.

Parameters:

aComparator - The comparator used for sorting. May not be null.

Returns:

A non-null list of element. Never null.

addObject

@Nonnull
default EChange addObject(@Nullable
                                    ELEMENTTYPE aElement)

add the provided element to the collection using Collection.add(Object) but returning a more structured return value.

Parameters:

aElement - The element to be add. May be null.

Returns:

EChange.CHANGED if the element was added successfully, EChange.UNCHANGED otherwise (e.g. because if is already contained).

See Also:

Collection.add(Object)

addIf

@Nonnull
default EChange addIf(@Nullable
                                ELEMENTTYPE aElement,
                                @Nullable
                                Predicate<? super ELEMENTTYPE> aFilter)

Add the passed element to this collection if passed predicate is fulfilled

Parameters:

aElement - The element to be added. May be null.

aFilter - The predicate to be executed. May not be null.

Returns:

EChange.CHANGED if the element was added, EChange.UNCHANGED otherwise.

See Also:

Collection.add(Object)

addIfNotNull

@Nonnull
default EChange addIfNotNull(@Nullable
                                       ELEMENTTYPE aElement)

Add the passed element to this collection if it is non-null. This is an optimized version for addIf(Object, Predicate) with the fixed predicate of != null.

Parameters:

aElement - The element to be added if non-null.

Returns:

EChange.CHANGED if the element was added, EChange.UNCHANGED otherwise.

See Also:

Collection.add(Object), addIf(Object, Predicate)

addAll

@Nonnull
default EChange addAll(@Nullable
                                 ELEMENTTYPE... aElements)

Add an array of elements to this collection.

Parameters:

aElements - The elements to be added. May be null.

Returns:

EChange.CHANGED if at least one element was added, EChange.UNCHANGED. Never null.

addAll

@Nonnull
default EChange addAll(@Nullable
                                 Iterable<? extends ELEMENTTYPE> aElements)

Add all elements of the passed iterable to this collection.

Parameters:

aElements - The elements to be added. May be null.

Returns:

EChange.CHANGED if at least one element was added, EChange.UNCHANGED. Never null.

addAll

@Nonnull
default EChange addAll(@Nullable
                                 Enumeration<? extends ELEMENTTYPE> aEnum)

Add all elements of the passed enumeration to this collection.

Parameters:

aEnum - The enumeration to be iterated and the elements to be added. May be null.

Returns:

EChange.CHANGED if at least one element was added, EChange.UNCHANGED. Never null.

addAll

@Nonnull
default EChange addAll(@Nullable
                                 Iterator<? extends ELEMENTTYPE> aIter)

Add all elements of the passed iterator to this collection.

Parameters:

aIter - The iterator to be iterated and the elements to be added. May be null.

Returns:

EChange.CHANGED if at least one element was added, EChange.UNCHANGED. Never null.

addAll

@Nonnull
default EChange addAll(@Nullable
                                 ELEMENTTYPE[] aElements,
                                 @Nullable
                                 Predicate<? super ELEMENTTYPE> aFilter)

Add all matching elements of an array this collection.

Parameters:

aElements - The elements to be added. May be null.

aFilter - The filter to be applied. May be null.

Returns:

EChange.CHANGED if at least one element was added, EChange.UNCHANGED. Never null.

Since:

8.5.2

addAll

@Nonnull
default EChange addAll(@Nullable
                                 Iterable<? extends ELEMENTTYPE> aElements,
                                 @Nullable
                                 Predicate<? super ELEMENTTYPE> aFilter)

Add all elements of the passed iterable to this collection.

Parameters:

aElements - The elements to be added. May be null.

aFilter - The filter to be applied. May be null.

Returns:

EChange.CHANGED if at least one element was added, EChange.UNCHANGED. Never null.

Since:

8.5.2

addAll

@Nonnull
default EChange addAll(@Nullable
                                 Enumeration<? extends ELEMENTTYPE> aEnum,
                                 @Nullable
                                 Predicate<? super ELEMENTTYPE> aFilter)

Add all elements of the passed enumeration to this collection.

Parameters:

aEnum - The enumeration to be iterated and the elements to be added. May be null.

aFilter - The filter to be applied. May be null.

Returns:

EChange.CHANGED if at least one element was added, EChange.UNCHANGED. Never null.

Since:

8.5.2

addAll

@Nonnull
default EChange addAll(@Nullable
                                 Iterator<? extends ELEMENTTYPE> aIter,
                                 @Nullable
                                 Predicate<? super ELEMENTTYPE> aFilter)

Add all elements of the passed iterator to this collection.

Parameters:

aIter - The iterator to be iterated and the elements to be added. May be null.

aFilter - The filter to be applied. May be null.

Returns:

EChange.CHANGED if at least one element was added, EChange.UNCHANGED. Never null.

Since:

8.5.2

addAllMapped

@Nonnull
default <SRCTYPE> EChange addAllMapped(@Nullable
                                                 Iterable<? extends SRCTYPE> aElements,
                                                 @Nonnull
                                                 Function<? super SRCTYPE,? extends ELEMENTTYPE> aMapper)

Add all passed elements after performing a mapping using the provided function.

Type Parameters:

SRCTYPE - The source type to be mapped from

Parameters:

aElements - The elements to be added after mapping. May be null.

aMapper - The mapping function to be executed for all provided elements. May not be null.

Returns:

EChange.CHANGED if at least one element was added, EChange.UNCHANGED. Never null.

addAllMapped

@Nonnull
default <SRCTYPE> EChange addAllMapped(@Nullable
                                                 SRCTYPE[] aElements,
                                                 @Nonnull
                                                 Function<? super SRCTYPE,? extends ELEMENTTYPE> aMapper)

Add all passed elements after performing a mapping using the provided function.

Type Parameters:

SRCTYPE - The source type to be mapped from

Parameters:

aElements - The elements to be added after mapping. May be null.

aMapper - The mapping function to be executed for all provided elements. May not be null.

Returns:

EChange.CHANGED if at least one element was added, EChange.UNCHANGED. Never null.

addAllMapped

@Nonnull
default <SRCTYPE> EChange addAllMapped(@Nullable
                                                 Iterable<? extends SRCTYPE> aElements,
                                                 @Nullable
                                                 Predicate<? super SRCTYPE> aFilter,
                                                 @Nonnull
                                                 Function<? super SRCTYPE,? extends ELEMENTTYPE> aMapper)

Add all passed elements matching the provided filter after performing a mapping using the provided function.

Type Parameters:

SRCTYPE - The source type to be mapped from

Parameters:

aElements - The elements to be added after mapping. May be null.

aFilter - The filter to be applied. May be null.

aMapper - The mapping function to be executed for all provided elements. May not be null.

Returns:

EChange.CHANGED if at least one element was added, EChange.UNCHANGED. Never null.

addAllMapped

@Nonnull
default <SRCTYPE> EChange addAllMapped(@Nullable
                                                 SRCTYPE[] aElements,
                                                 @Nullable
                                                 Predicate<? super SRCTYPE> aFilter,
                                                 @Nonnull
                                                 Function<? super SRCTYPE,? extends ELEMENTTYPE> aMapper)

Add all passed elements matching the provided filter after performing a mapping using the provided function.

Type Parameters:

SRCTYPE - The source type to be mapped from

Parameters:

aElements - The elements to be added after mapping. May be null.

aFilter - The filter to be applied. May be null.

aMapper - The mapping function to be executed for all provided elements. May not be null.

Returns:

EChange.CHANGED if at least one element was added, EChange.UNCHANGED. Never null.

addAllMapped

@Nonnull
default <SRCTYPE> EChange addAllMapped(@Nullable
                                                 Iterable<? extends SRCTYPE> aElements,
                                                 @Nonnull
                                                 Function<? super SRCTYPE,? extends ELEMENTTYPE> aMapper,
                                                 @Nullable
                                                 Predicate<? super ELEMENTTYPE> aFilter)

Add all passed elements matching the provided filter after performing a mapping using the provided function.

Type Parameters:

SRCTYPE - The source type to be mapped from

Parameters:

aElements - The elements to be added after mapping. May be null.

aMapper - The mapping function to be executed for all provided elements. May not be null.

aFilter - The filter to be applied on the mapped element. May be null.

Returns:

EChange.CHANGED if at least one element was added, EChange.UNCHANGED. Never null.

Since:

8.5.2

addAllMapped

@Nonnull
default <SRCTYPE> EChange addAllMapped(@Nullable
                                                 SRCTYPE[] aElements,
                                                 @Nonnull
                                                 Function<? super SRCTYPE,? extends ELEMENTTYPE> aMapper,
                                                 @Nullable
                                                 Predicate<? super ELEMENTTYPE> aFilter)

Add all passed elements matching the provided filter after performing a mapping using the provided function.

Type Parameters:

SRCTYPE - The source type to be mapped from

Parameters:

aElements - The elements to be added after mapping. May be null.

aMapper - The mapping function to be executed for all provided elements. May not be null.

aFilter - The filter to be applied on the mapped element. May be null.

Returns:

EChange.CHANGED if at least one element was added, EChange.UNCHANGED. Never null.

Since:

8.5.2

set

@Nonnull
default EChange set(@Nullable
                              ELEMENTTYPE aValue)

Clear all elements and add only the passed value.

Parameters:

aValue - The value to be added. May be null.

Returns:

EChange.CHANGED if something was changed, EChange.UNCHANGED otherwise.

See Also:

Collection.clear(), Collection.add(Object)

setAll

@Nonnull
default EChange setAll(@Nullable
                                 Iterable<? extends ELEMENTTYPE> aValues)

Clear all elements and add all provided values. If no value is provided, the collection is empty afterwards.

Parameters:

aValues - The values to be added. May be null.

Returns:

EChange.CHANGED if something was changed, EChange.UNCHANGED otherwise.

See Also:

removeAll(), addAll(Iterable)

setAll

@Nonnull
default EChange setAll(@Nullable
                                 ELEMENTTYPE... aValues)

Clear all elements and add all provided values. If no value is provided, the collection is empty afterwards.

Parameters:

aValues - The values to be added. May be null.

Returns:

EChange.CHANGED if something was changed, EChange.UNCHANGED otherwise.

See Also:

removeAll(), addAll(Object...)

removeAll

@Nonnull
default EChange removeAll()

Remove all elements from this collection. This is similar to Collection.clear() but it returns a different value whether something was cleared or not.

Returns:

EChange.CHANGED if the collection was not empty and something was removed, EChange.UNCHANGED otherwise.

See Also:

Collection.clear()

removeObject

@Nonnull
default EChange removeObject(@Nullable
                                       ELEMENTTYPE aElement)

Remove the provided element from the collection using Collection.remove(Object) but returning a more structured return value.

Parameters:

aElement - The element to be removed. May be null.

Returns:

EChange.CHANGED if the element was removed successfully, EChange.UNCHANGED otherwise.

See Also:

Collection.remove(Object)

getAsUnmodifiable

@Nonnull
 @CodingStyleguideUnaware
default Collection<ELEMENTTYPE> getAsUnmodifiable()

Returns:

An unmodifiable version of this collection. Never null .

See Also:

Collections

iterator2

@Nonnull
default IIterableIterator<ELEMENTTYPE> iterator2()

Returns:

An iterable iterator on this collection. This is similar to Collection.iterator() but the returned type is more flexible. Never null.

See Also:

Collection.iterator(), IterableIterator