GroupingState (apache-cassandra API)

java.lang.Object
- org.apache.cassandra.db.aggregation.GroupingState

```
public final class GroupingState
extends java.lang.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 GroupingState EMPTY_STATE

static GroupingState.Serializer serializer

Constructor Summary

Constructors
Constructor Description

GroupingState(java.nio.ByteBuffer partitionKey, Clustering<?> clustering)

Method Summary

All Methods Instance Methods Concrete Methods
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.
`java.nio.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 Detail
  - serializer
```
public static final GroupingState.Serializer serializer
```
  - EMPTY_STATE
```
public static final GroupingState EMPTY_STATE
```
- Constructor Detail
  - GroupingState
```
public GroupingState(java.nio.ByteBuffer partitionKey,
                     Clustering<?> clustering)
```
- Method Detail
  - partitionKey
```
public java.nio.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.