Package com.apple.foundationdb.record.provider.foundationdb.cursors

Class MergeCursorState<T>

java.lang.Object

com.apple.foundationdb.record.provider.foundationdb.cursors.MergeCursorState<T>

Type Parameters:

T - the type of elements returned by the underlying cursor

All Implemented Interfaces:

AutoCloseable

@API(INTERNAL)
public class MergeCursorState<T>
extends Object
implements AutoCloseable

A holder for mutable state needed to track one of the children cursors of some merge operation. This includes the cursor itself as well as information tracking the progress including continuation information. Subclasses may add additional information such as a comparison key or value (for ordered cursors).

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	MergeCursorState(RecordCursor<T> cursor, RecordCursorContinuation continuation)

Method Summary

Modifier and Type	Method	Description
void	close()
void	consume()
static <T> MergeCursorState<T>	from(Function<byte[],RecordCursor<T>> cursorFunction, RecordCursorContinuation continuation)
RecordCursorContinuation	getContinuation()
RecordCursor<T>	getCursor()
Executor	getExecutor()
CompletableFuture<RecordCursorResult<T>>	getOnNextFuture()
RecordCursorResult<T>	getResult()
protected void	handleNextCursorResult(RecordCursorResult<T> cursorResult)
boolean	mightHaveNext()	Return whether this cursor may return a result in the future.

Methods inherited from class java.lang.Object

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

Constructor Detail

MergeCursorState

protected MergeCursorState(@Nonnull
                           RecordCursor<T> cursor,
                           @Nonnull
                           RecordCursorContinuation continuation)

Method Detail

handleNextCursorResult

protected void handleNextCursorResult(@Nonnull
                                      RecordCursorResult<T> cursorResult)

getOnNextFuture

@Nonnull
public CompletableFuture<RecordCursorResult<T>> getOnNextFuture()

consume

public void consume()

mightHaveNext

public boolean mightHaveNext()

Return whether this cursor may return a result in the future. In particular, this will return true if this cursor has either not returned its first result or if the most recent result had a next element.

Returns:

whether the cursor might have more results

getResult

@Nullable
public RecordCursorResult<T> getResult()

close

public void close()

Specified by:

close in interface AutoCloseable

getExecutor

@Nonnull
public Executor getExecutor()

getCursor

@Nonnull
public RecordCursor<T> getCursor()

getContinuation

@Nonnull
public RecordCursorContinuation getContinuation()

from

@Nonnull
public static <T> MergeCursorState<T> from(@Nonnull
                                           Function<byte[],RecordCursor<T>> cursorFunction,
                                           @Nonnull
                                           RecordCursorContinuation continuation)