org.apache.cassandra.db

Class Clustering

java.lang.Object

org.apache.cassandra.db.AbstractClusteringPrefix

org.apache.cassandra.db.Clustering

All Implemented Interfaces:

IMeasurableMemory, Clusterable, ClusteringPrefix

public class Clustering
extends AbstractClusteringPrefix

The clustering column values for a row.

A Clustering is a ClusteringPrefix that must always be "complete", i.e. have as many values as there is clustering columns in the table it is part of. It is the clustering prefix used by rows.

Note however that while it's size must be equal to the table clustering size, a clustering can have null values, and this mostly for thrift backward compatibility (in practice, if a value is null, all of the following ones will be too because that's what thrift allows, but it's never assumed by the code so we could start generally allowing nulls for clustering columns if we wanted to).

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	Clustering.Serializer Serializer for Clustering object.

Nested classes/interfaces inherited from interface org.apache.cassandra.db.ClusteringPrefix

ClusteringPrefix.Deserializer, ClusteringPrefix.Kind

Field Summary

Fields

Modifier and Type	Field and Description
static Clustering	EMPTY Empty clustering for tables having no clustering columns.
static Clustering.Serializer	serializer
static Clustering	STATIC_CLUSTERING The special cased clustering used by all static rows.

Fields inherited from class org.apache.cassandra.db.AbstractClusteringPrefix

EMPTY_VALUES_ARRAY, kind, values

Constructor Summary

Constructors

Constructor and Description
Clustering(java.nio.ByteBuffer... values)

Method Summary

Modifier and Type	Method and Description
Clustering	copy(AbstractAllocator allocator)
ClusteringPrefix.Kind	kind()
java.lang.String	toCQLString(CFMetaData metadata)
java.lang.String	toString(CFMetaData metadata) Generates a proper string representation of the prefix.

Methods inherited from class org.apache.cassandra.db.AbstractClusteringPrefix

clustering, dataSize, digest, equals, get, getRawValues, hashCode, size, unsharedHeapSize, unsharedHeapSizeExcludingData

Methods inherited from class java.lang.Object

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

Field Detail

serializer

public static final Clustering.Serializer serializer

STATIC_CLUSTERING

public static final Clustering STATIC_CLUSTERING

The special cased clustering used by all static rows. It is a special case in the sense that it's always empty, no matter how many clustering columns the table has.

EMPTY

public static final Clustering EMPTY

Empty clustering for tables having no clustering columns.

Constructor Detail

Clustering

public Clustering(java.nio.ByteBuffer... values)

Method Detail

kind

public ClusteringPrefix.Kind kind()

Specified by:

kind in interface ClusteringPrefix

Overrides:

kind in class AbstractClusteringPrefix

copy

public Clustering copy(AbstractAllocator allocator)

toString

public java.lang.String toString(CFMetaData metadata)

Description copied from interface: ClusteringPrefix

Generates a proper string representation of the prefix.

Parameters:

metadata - the metadata for the table the clustering prefix is of.

Returns:

a human-readable string representation fo this prefix.

toCQLString

public java.lang.String toCQLString(CFMetaData metadata)