Package org.apache.cassandra.db.aggregation

Class GroupingState

java.lang.Object

org.apache.cassandra.db.aggregation.GroupingState

public final class GroupingState
extends Object

GroupMaker state.

The state contains the primary key of the last row that has been processed by the previous GroupMaker used. It can be passed to a GroupMaker to allow to resuming the grouping.

GroupingState is only used for internal paging. When a new page is requested by a client the initial state will always be empty.

If the state has a partition key but no clustering, it means that the previous group ended at the end of the previous partition. If the clustering is not null it means that we are in the middle of a group.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	GroupingState.Serializer

Field Summary

Fields

Modifier and Type	Field	Description
static final GroupingState	EMPTY_STATE
static final GroupingState.Serializer	serializer

Constructor Summary

Constructors

Constructor	Description
GroupingState(ByteBuffer partitionKey, Clustering<?> clustering)

Method Summary

Modifier and Type	Method	Description
Clustering<?>	clustering()	Returns the last row clustering or null if either no rows has been processed yet or the last row was a static row.
boolean	hasClustering()	Checks if the state contains a Clustering for the last row that has been processed.
ByteBuffer	partitionKey()	Returns the last row partition key or null if no rows has been processed yet.

Methods inherited from class java.lang.Object

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

Field Details

serializer

public static final GroupingState.Serializer serializer

EMPTY_STATE

public static final GroupingState EMPTY_STATE

Constructor Details

GroupingState

public GroupingState(ByteBuffer partitionKey,
 Clustering<?> clustering)

Method Details

partitionKey

public ByteBuffer partitionKey()

Returns the last row partition key or null if no rows has been processed yet.

Returns:

the last row partition key or null if no rows has been processed yet

clustering

public Clustering<?> clustering()

Returns the last row clustering or null if either no rows has been processed yet or the last row was a static row.

Returns:

he last row clustering or null if either no rows has been processed yet or the last row was a static row

hasClustering

public boolean hasClustering()

Checks if the state contains a Clustering for the last row that has been processed.

Returns:

true if the state contains a Clustering for the last row that has been processed, false otherwise.