Package nz.org.riskscape.engine.relation

Interface TupleIterator

All Superinterfaces:

AutoCloseable, Iterator<Tuple>

All Known Implementing Classes:

Singleton

public interface TupleIterator
extends Iterator<Tuple>, AutoCloseable

Brings together the AutoCloseable and Iterator interface fo Iterators that come from Relations, so that iterators can clean up any resources they are derived from.

Field Summary

Fields

Modifier and Type	Field	Description
static final TupleIterator	EMPTY	An always empty TupleIterator, a bit like Collections.emptyIterator()

Method Summary

Modifier and Type	Method	Description
default void	close()
default <A, R> R	collect(Collector<? super Tuple,A,R> collector)	Collect all values from this tuple iterator in to the given Collector, and ensures the iterator is closed.
default void	forEachRemaining(Consumer<? super Tuple> action)	Pass each tuple to the given consumer, closing the iterator once complete (or if in exception is thrown)
static TupleIterator	singleton(Tuple tuple)
static TupleIterator	wrapped(@NonNull Iterator<Tuple> iterator, @NonNull Optional<Runnable> onClose)	Wraps a normal iterator with this interface, making the close a noop.
static <T> TupleIterator	wrappedAndMapped(@NonNull Iterator<T> iterator, @NonNull Function<T,Tuple> mapper)	Wraps a possibly normal Iterator with this interface, applying the given mapping functions to values yielded from the Tuple

Methods inherited from interface java.util.Iterator

hasNext, next, remove

Field Details

EMPTY

static final TupleIterator EMPTY

An always empty TupleIterator, a bit like Collections.emptyIterator()

Method Details

wrapped

static TupleIterator wrapped(@NonNull
 @NonNull Iterator<Tuple> iterator,
 @NonNull
 @NonNull Optional<Runnable> onClose)

Wraps a normal iterator with this interface, making the close a noop. TODO - maybe add an optional callback for closing?

wrappedAndMapped

static <T> TupleIterator wrappedAndMapped(@NonNull
 @NonNull Iterator<T> iterator,
 @NonNull
 @NonNull Function<T,Tuple> mapper)

Wraps a possibly normal Iterator with this interface, applying the given mapping functions to values yielded from the Tuple

close

default void close()

Specified by:

close in interface AutoCloseable

collect

default <A,
R> R collect(Collector<? super Tuple,A,R> collector)

Collect all values from this tuple iterator in to the given Collector, and ensures the iterator is closed.

Returns:

the result of Collection

forEachRemaining

default void forEachRemaining(Consumer<? super Tuple> action)

Pass each tuple to the given consumer, closing the iterator once complete (or if in exception is thrown)

Specified by:

forEachRemaining in interface Iterator<Tuple>

singleton

static TupleIterator singleton(Tuple tuple)

Returns:

a TupleIterator that yields a single, fixed result.