org.apache.jena.util.iterator

Interface ExtendedIterator<T>

Type Parameters:

T - the type of element over which an instance of ExtendedIterator iterates

All Superinterfaces:

ClosableIterator<T>, Iterator<T>

All Known Subinterfaces:

NodeIterator, NsIterator, ResIterator, RSIterator, StmtIterator, TripleIterator

All Known Implementing Classes:

ContNodeIteratorImpl, FilterIterator, LazyIterator, Map1Iterator, MapFilterIterator, NiceIterator, NodeIteratorImpl, NsIteratorImpl, NullIterator, ObjectIterator, RandomOrderIterator, ResIteratorImpl, RSIteratorImpl, SeqNodeIteratorImpl, SingletonIterator, StmtIteratorImpl, StoreTripleIterator, TrackingTripleIterator, WrappedIterator

public interface ExtendedIterator<T>
extends ClosableIterator<T>

An ExtendedIterator is a ClosableIterator on which other operations are defined for convenience in iterator composition: composition, filtering in, filtering out, and element mapping.
NOTE that the result of these operations consumes the base iterator(s); they do not make independent copies.
The canonical implementation of ExtendedIterator is NiceIterator, which also defines static methods for these operations that will work on any ClosableIterators.

Method Summary

Modifier and Type	Method and Description
<X extends T> ExtendedIterator<T>	andThen(Iterator<X> other) return a new iterator which delivers all the elements of this iterator and then all the elements of the other iterator.
ExtendedIterator<T>	filterDrop(Predicate<T> f) return a new iterator containing only the elements of _this_ which are rejected by the filter _f_.
ExtendedIterator<T>	filterKeep(Predicate<T> f) return a new iterator containing only the elements of _this_ which pass the filter _f_.
<U> ExtendedIterator<U>	mapWith(Function<T,U> map1) return a new iterator where each element is the result of applying _map1_ to the corresponding element of _this_.
default Optional<T>	nextOptional() Answer with an Optional.
T	removeNext() Answer the next object, and remove it.
List<T>	toList() Answer a list of the [remaining] elements of this iterator, in order, consuming this iterator.
Set<T>	toSet() Answer a set of the [remaining] elements of this iterator, consuming this iterator.

Methods inherited from interface org.apache.jena.util.iterator.ClosableIterator

close

Methods inherited from interface java.util.Iterator

forEachRemaining, hasNext, next, remove

Method Detail

removeNext

T removeNext()

Answer the next object, and remove it. Equivalent to next(); remove().

andThen

<X extends T> ExtendedIterator<T> andThen(Iterator<X> other)

return a new iterator which delivers all the elements of this iterator and then all the elements of the other iterator. Does not copy either iterator; they are consumed as the result iterator is consumed.

filterKeep

ExtendedIterator<T> filterKeep(Predicate<T> f)

return a new iterator containing only the elements of _this_ which pass the filter _f_. The order of the elements is preserved. Does not copy _this_, which is consumed as the result is consumed.

filterDrop

ExtendedIterator<T> filterDrop(Predicate<T> f)

return a new iterator containing only the elements of _this_ which are rejected by the filter _f_. The order of the elements is preserved. Does not copy _this_, which is consumed as the result is consumed.

mapWith

<U> ExtendedIterator<U> mapWith(Function<T,U> map1)

return a new iterator where each element is the result of applying _map1_ to the corresponding element of _this_. _this_ is not copied; it is consumed as the result is consumed.

toList

List<T> toList()

Answer a list of the [remaining] elements of this iterator, in order, consuming this iterator.

toSet

Set<T> toSet()

Answer a set of the [remaining] elements of this iterator, consuming this iterator.

nextOptional

default Optional<T> nextOptional()

Answer with an Optional. This operation assumes that the ExtendedIterator does not return null for next(). If it does, NullPointerException is thrown.

• If there is no next, return Optional.empty()
• If the next object exists, and is not null, return that in the Optional.
• If the next object exists, and is null, throw NullPointerException