Package com.mongodb.async

Interface AsyncBatchCursor<T>

Type Parameters:

T - The type of documents the cursor contains

All Superinterfaces:

AutoCloseable, Closeable

All Known Subinterfaces:

MapReduceAsyncBatchCursor<T>

public interface AsyncBatchCursor<T>
extends Closeable

MongoDB returns query results as batches, and this interface provides an asynchronous iterator over those batches. The first call to the next method will return the first batch, and subsequent calls will trigger an asynchronous request to get the next batch of results. Clients can control the batch size by setting the batchSize property between calls to next.

Since:

3.0

MongoDB documentation

OP_GET_MORE

Method Summary

Modifier and Type	Method	Description
void	close()
int	getBatchSize()	Gets the batch size to use when requesting the next batch.
boolean	isClosed()	Return true if the AsyncBatchCursor has been closed
void	next(SingleResultCallback<List<T>> callback)	Returns the next batch of results.
void	setBatchSize(int batchSize)	Sets the batch size to use when requesting the next batch.
void	tryNext(SingleResultCallback<List<T>> callback)	A special next() case that returns the next batch if available or null.

Method Detail

next

void next(SingleResultCallback<List<T>> callback)

Returns the next batch of results. A tailable cursor will block until another batch exists. After the last batch, the next call to this method will execute the callback with a null result to indicate that there are no more batches available and the cursor has been closed.

Parameters:

callback - callback to receive the next batch of results

Throws:

NoSuchElementException - if no next batch exists

tryNext

void tryNext(SingleResultCallback<List<T>> callback)

A special next() case that returns the next batch if available or null.

Tailable cursors are an example where this is useful. A call to tryNext() may return null, but in the future calling tryNext() would return a new batch if a document had been added to the capped collection.

Parameters:

callback - callback to receive the next batch of results

Since:

3.6

MongoDB documentation

Tailable Cursor

setBatchSize

void setBatchSize(int batchSize)

Sets the batch size to use when requesting the next batch. This is the number of documents to request in the next batch.

Parameters:

batchSize - the non-negative batch size. 0 means to use the server default.

getBatchSize

int getBatchSize()

Gets the batch size to use when requesting the next batch. This is the number of documents to request in the next batch.

Returns:

the non-negative batch size. 0 means to use the server default.

isClosed

boolean isClosed()

Return true if the AsyncBatchCursor has been closed

Returns:

true if the AsyncBatchCursor has been closed

close

void close()

Specified by:

close in interface AutoCloseable

Specified by:

close in interface Closeable