org.apache.cassandra.service.pager

Class AggregationQueryPager.GroupByPartitionIterator

java.lang.Object

org.apache.cassandra.service.pager.AggregationQueryPager.GroupByPartitionIterator

All Implemented Interfaces:

java.lang.AutoCloseable, java.util.Iterator<RowIterator>, BasePartitionIterator<RowIterator>, PartitionIterator, CloseableIterator<RowIterator>

Direct Known Subclasses:

AggregationQueryPager.AggregationPartitionIterator

Enclosing class:

AggregationQueryPager

public class AggregationQueryPager.GroupByPartitionIterator
extends java.lang.Object
implements PartitionIterator

PartitionIterator that automatically fetch a new sub-page of data if needed when the current iterator is exhausted.

Constructor Summary

Constructors

Constructor and Description
GroupByPartitionIterator(int pageSize, ConsistencyLevel consistency, ClientState clientState, Dispatcher.RequestTime requestTime)
GroupByPartitionIterator(int pageSize, ReadExecutionController executionController, Dispatcher.RequestTime requestTime)

Method Summary

Modifier and Type	Method and Description
void	close()
protected int	computeSubPageSize(int pageSize, int counted) Computes the size of the next sub-page to retrieve.
boolean	hasNext()
protected boolean	isDone(int pageSize, int counted)
RowIterator	next()
protected QueryPager	updatePagerLimit(QueryPager pager, DataLimits limits, java.nio.ByteBuffer lastPartitionKey, Clustering<?> lastClustering) Updates the pager with the new limits if needed.

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.apache.cassandra.utils.CloseableIterator

empty, wrap

Methods inherited from interface java.util.Iterator

forEachRemaining, remove

Constructor Detail

GroupByPartitionIterator

public GroupByPartitionIterator(int pageSize,
                                ConsistencyLevel consistency,
                                ClientState clientState,
                                Dispatcher.RequestTime requestTime)

GroupByPartitionIterator

public GroupByPartitionIterator(int pageSize,
                                ReadExecutionController executionController,
                                Dispatcher.RequestTime requestTime)

Method Detail

close

public final void close()

Specified by:

close in interface java.lang.AutoCloseable

Specified by:

close in interface BasePartitionIterator<RowIterator>

Specified by:

close in interface CloseableIterator<RowIterator>

hasNext

public final boolean hasNext()

Specified by:

hasNext in interface java.util.Iterator<RowIterator>

isDone

protected boolean isDone(int pageSize,
                         int counted)

updatePagerLimit

protected QueryPager updatePagerLimit(QueryPager pager,
                                      DataLimits limits,
                                      java.nio.ByteBuffer lastPartitionKey,
                                      Clustering<?> lastClustering)

Updates the pager with the new limits if needed.

Parameters:

pager - the pager previoulsy used

limits - the DataLimits

lastPartitionKey - the partition key of the last row returned

lastClustering - the clustering of the last row returned

Returns:

the pager to use to query the next page of data

computeSubPageSize

protected int computeSubPageSize(int pageSize,
                                 int counted)

Computes the size of the next sub-page to retrieve.

Parameters:

pageSize - the top-level page size

counted - the number of result returned so far by the previous sub-pages

Returns:

the size of the next sub-page to retrieve

next

public final RowIterator next()

Specified by:

next in interface java.util.Iterator<RowIterator>