org.apache.cassandra.db.aggregation

## Class AggregationSpecification

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

-     public abstract class AggregationSpecification
      extends java.lang.Object

  Defines how rows should be grouped for creating aggregates.

- - ### Nested Class Summary

    Nested Classes
    Modifier and Type | Class and Description
    --- | ---
    `static class` | `AggregationSpecification.Kind` The `AggregationSpecification` kinds.
    `static class` | `AggregationSpecification.Serializer`

  - ### Field Summary

    Fields
    Modifier and Type | Field and Description
    --- | ---
    `static AggregationSpecification` | `AGGREGATE_EVERYTHING` `AggregationSpecification` that group all the row together.
    `static AggregationSpecification.Serializer` | `serializer`

  - ### Method Summary

    All Methods Static Methods Instance Methods Abstract Methods Concrete Methods
    Modifier and Type | Method and Description
    --- | ---
    `static AggregationSpecification` | `aggregatePkPrefix(ClusteringComparator comparator, int clusteringPrefixSize)` Creates a new `AggregationSpecification` instance that will build aggregates based on primary key columns.
    `AggregationSpecification.Kind` | `kind()` Returns the `AggregationSpecification` kind.
    `GroupMaker` | `newGroupMaker()` Creates a new `GroupMaker` instance.
    `abstract GroupMaker` | `newGroupMaker(GroupingState state)` Creates a new `GroupMaker` instance.

    - ### Methods inherited from class java.lang.Object

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

- - ### Field Detail

    - #### serializer

          public static final AggregationSpecification.Serializer serializer

    - #### AGGREGATE_EVERYTHING

          public static final AggregationSpecification AGGREGATE_EVERYTHING

      `AggregationSpecification` that group all the row together.

  - ### Method Detail

    - #### kind

          public AggregationSpecification.Kind kind()

      Returns the `AggregationSpecification` kind.
      Returns:
        the `AggregationSpecification` kind

    - #### newGroupMaker

          public final GroupMaker newGroupMaker()

      Creates a new `GroupMaker` instance.
      Returns:
        a new `GroupMaker` instance

    - #### newGroupMaker

          public abstract GroupMaker newGroupMaker(GroupingState state)

      Creates a new `GroupMaker` instance.
      Parameters:
        `state` - `GroupMaker` state
      Returns:
        a new `GroupMaker` instance

    - #### aggregatePkPrefix

          public static AggregationSpecification aggregatePkPrefix(ClusteringComparator comparator,
                                                                   int clusteringPrefixSize)

      Creates a new `AggregationSpecification` instance that will build aggregates based on primary key columns.
      Parameters:
        `comparator` - the comparator used to compare the clustering prefixes
        `clusteringPrefixSize` - the number of clustering columns used to create the aggregates
      Returns:
        a new `AggregationSpecification` instance that will build aggregates based on primary key columns

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