com.allanbank.mongodb.client

Class MongoIterator

java.lang.Object

com.allanbank.mongodb.client.MongoIterator

All Implemented Interfaces:

ClosableIterator<Document>, Iterable<Document>, Iterator<Document>

public class MongoIterator
extends Object
implements ClosableIterator<Document>

Iterator over the results of the MongoDB cursor.

API Warning:

This class is NOT part of the drivers API. This class may be mutated in incompatible ways between any two releases of the driver.

Copyright ©:

2011-2012, Allanbank Consulting, Inc., All Rights Reserved

Constructor Summary

Constructors

Constructor and Description
MongoIterator(Query originalQuery, Client client, String server, Reply reply) Create a new MongoDBInterator.

Method Summary

Methods

Modifier and Type	Method and Description
void	close() Close the iterator and release any resources it is holding.
int	getBatchSize() Returns the size for batches of documents that are requested.
ReadPreference	getReadPerference() Returns the iterator's read preference which points to the original server performing the query.
boolean	hasNext()
Iterator<Document>	iterator()
protected void	loadDocuments() Loads more documents into the iterator.
protected List<Document>	loadDocuments(boolean blockForTailable) Loads more documents into the iterator.
Document	next()
int	nextBatchSize() Computes the size for the next batch of documents to get.
void	remove()
void	setBatchSize(int batchSize) Sets the size for future batch sizes.

Methods inherited from class java.lang.Object

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

Constructor Detail

MongoIterator

public MongoIterator(Query originalQuery,
             Client client,
             String server,
             Reply reply)

Create a new MongoDBInterator.

Parameters:

originalQuery - The original query being iterated over.

client - The client for issuing more requests.

server - The server that received the original query request.

reply - The initial results of the query that are available.

Method Detail

close

public void close()

Close the iterator and release any resources it is holding.

Overridden to close the iterator and send a KillCursors for the open cursor, if any.

Specified by:

close in interface ClosableIterator<Document>

getBatchSize

public int getBatchSize()

Returns the size for batches of documents that are requested.

Overridden to get the batch size from the original query or set explicitly.

Specified by:

getBatchSize in interface ClosableIterator<Document>

Returns:

The size of the batches of documents that are requested.

getReadPerference

public ReadPreference getReadPerference()

Returns the iterator's read preference which points to the original server performing the query.

Returns:

The iterator's read preference which points to the original server performing the query.

hasNext

public boolean hasNext()

Overridden to return true if there are more documents.

Specified by:

hasNext in interface Iterator<Document>

iterator

public Iterator<Document> iterator()

Overridden to return this iterator.

Specified by:

iterator in interface Iterable<Document>

next

public Document next()

Overridden to return the next document from the query.

Specified by:

next in interface Iterator<Document>

See Also:

Iterator.next()

nextBatchSize

public int nextBatchSize()

Computes the size for the next batch of documents to get.

Returns:

The returnNex

remove

public void remove()

Overridden to throw and UnsupportedOperationException.

Specified by:

remove in interface Iterator<Document>

See Also:

Iterator.remove()

setBatchSize

public void setBatchSize(int batchSize)

Sets the size for future batch sizes.

Overridden to set the batch size.

Specified by:

setBatchSize in interface ClosableIterator<Document>

Parameters:

batchSize - The size to request for future batch sizes.

loadDocuments

protected void loadDocuments()
                      throws RuntimeException

Loads more documents into the iterator. This iterator issues a get_more command as soon as the previous results start to be used.

Throws:

RuntimeException - On a failure to load documents.

loadDocuments

protected List<Document> loadDocuments(boolean blockForTailable)
                                throws RuntimeException

Loads more documents into the iterator. This iterator issues a get_more command as soon as the previous results start to be used.

Parameters:

blockForTailable - If true then the method will recursively call itself on a tailable cursor with no results. This makes the call blocking. It false then the call will not block. This is used by the method to ensure that the outermost load blocks but the recursion is not inifinite.

Returns:

The list of loaded documents.

Throws:

RuntimeException - On a failure to load documents.