Package com.mongodb.operation

Interface BatchCursor<T>

Type Parameters:

T - The type of documents the cursor contains

All Superinterfaces:

AutoCloseable, Closeable, Iterator<List<T>>

All Known Subinterfaces:

MapReduceBatchCursor<T>

@NotThreadSafe
public interface BatchCursor<T>
extends Iterator<List<T>>, Closeable

MongoDB returns query results as batches, and this interface provideds an iterator over those batches. The first call to the next method will return the first batch, and subsequent calls will trigger a 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.
ServerAddress	getServerAddress()	Returns the server address
ServerCursor	getServerCursor()	Returns the server cursor
boolean	hasNext()	Returns true if another batch of results exists.
List<T>	next()	Returns the next batch of results.
void	setBatchSize(int batchSize)	Sets the batch size to use when requesting the next batch.
List<T>	tryNext()	A special next() case that returns the next batch if available or null.

Methods inherited from interface java.util.Iterator

forEachRemaining, remove

Method Detail

close

void close()

Specified by:

close in interface AutoCloseable

Specified by:

close in interface Closeable

hasNext

boolean hasNext()

Returns true if another batch of results exists. A tailable cursor will block until another batch exists.

Specified by:

hasNext in interface Iterator<T>

Returns:

true if another batch exists

next

List<T> next()

Returns the next batch of results. A tailable cursor will block until another batch exists.

Specified by:

next in interface Iterator<T>

Returns:

the next batch of results

Throws:

NoSuchElementException - if no next batch exists

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.

tryNext

List<T> tryNext()

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.

Returns:

the next batch if available or null.

MongoDB documentation

Tailable Cursor

getServerCursor

ServerCursor getServerCursor()

Returns the server cursor

Returns:

ServerCursor

getServerAddress

ServerAddress getServerAddress()

Returns the server address

Returns:

ServerAddress