Package com.apple.foundationdb.async

Interface AsyncPeekCallbackIterator<T>

Type Parameters:

T - type of elements returned by the scan

All Superinterfaces:

AsyncIterator<T>, AsyncPeekIterator<T>, Iterator<T>

public interface AsyncPeekCallbackIterator<T>
extends AsyncPeekIterator<T>

An AsyncPeekCallbackIterator is an extension of the AsyncPeekIterator interface that can be given a callback to call after each time it advances. Note that the AsyncPeekCallbackIterator is mostly a tag interface and does not contain any logic for executing the callback after yielding each result; conforming implementations must implement that logic.

Method Summary

Modifier and Type	Method	Description
Consumer<T>	getCallback()	Return the callback that this iterator calls before a new result is returned by AsyncIterator.next().
void	setCallback(Consumer<T> callback)	Set the callback to the provided Consumer.
static <T> AsyncPeekCallbackIterator<T>	wrap(AsyncIterator<T> iterator, Consumer<T> callback)	Wrap an AsyncIterator with an AsyncPeekCallbackIterator.

Methods inherited from interface com.apple.foundationdb.async.AsyncIterator

cancel, hasNext, next, onHasNext

Methods inherited from interface com.apple.foundationdb.async.AsyncPeekIterator

peek

Methods inherited from interface java.util.Iterator

forEachRemaining, remove

Method Detail

wrap

static <T> AsyncPeekCallbackIterator<T> wrap(@Nonnull
                                             AsyncIterator<T> iterator,
                                             @Nonnull
                                             Consumer<T> callback)

Wrap an AsyncIterator with an AsyncPeekCallbackIterator. The returned iterator returns the same sequence of elements as the supplied AsyncIterator instance in the same order. The wrapping implementation is free to advance the underlying iterator, so it is unsafe to modify iterator directly after calling this method. The returned iterator is also not thread safe, so concurrent calls to onHasNext, for example, may lead to unexpected behavior.

Type Parameters:

T - type of items returned by the scan

Parameters:

iterator - AsyncIterator to wrap

callback - a callback to call when AsyncIterator.next() produces a result

Returns:

an iterator over the same values as iterator that supports peek and callback semantics

setCallback

void setCallback(@Nonnull
                 Consumer<T> callback)

Set the callback to the provided Consumer.

Parameters:

callback - a consumer to call when a new result is produced by AsyncIterator.next()

getCallback

@Nonnull
Consumer<T> getCallback()

Return the callback that this iterator calls before a new result is returned by AsyncIterator.next().

Returns:

the callback that this iterator calls before a new result is returned by AsyncIterator.next();W