All Superinterfaces:

Clusterable<V>, IMeasurableMemory

All Known Subinterfaces:

Clustering<V>, ClusteringBound<V>, ClusteringBoundary<V>, ClusteringBoundOrBoundary<V>

All Known Implementing Classes:

AbstractArrayClusteringPrefix, AbstractBufferClusteringPrefix, AbstractOnHeapClusteringPrefix, ArrayClustering, ArrayClusteringBound, ArrayClusteringBoundary, ArrayClusteringBoundOrBoundary, BufferClustering, BufferClusteringBound, BufferClusteringBoundary, BufferClusteringBoundOrBoundary, NativeClustering
```
public interface ClusteringPrefix<V>
extends IMeasurableMemory, Clusterable<V>
```
A clustering prefix is the unit of what a ClusteringComparator can compare.
It holds values for the clustering columns of a table (potentially only a prefix of all of them) and has a "kind" that allows us to implement slices with inclusive and exclusive bounds.
In practice, ClusteringPrefix is just the common parts to its 3 main subtype: Clustering and ClusteringBound/ClusteringBoundary, where: 1) Clustering represents the clustering values for a row, i.e. the values for it's clustering columns. 2) ClusteringBound represents a bound (start or end) of a slice (of rows) or a range tombstone. 3) ClusteringBoundary represents the threshold between two adjacent range tombstones. See those classes for more details.

Nested Class Summary

Nested Classes
Modifier and Type	Interface	Description
`static class`	`ClusteringPrefix.Deserializer`	Helper class that makes the deserialization of clustering prefixes faster.
`static class`	`ClusteringPrefix.Kind`	The kind of clustering prefix this actually is.
`static class`	`ClusteringPrefix.Serializer`

Field Summary

Fields
Modifier and Type Field Description

static ClusteringPrefix.Serializer serializer

Method Summary

All Methods Static Methods Instance Methods Abstract Methods Default Methods
Modifier and Type	Method	Description
`ValueAccessor<V>`	`accessor()`
`ClusteringBound<V>`	`asEndBound()`	Returns this prefix as an end bound.
`ClusteringBound<V>`	`asStartBound()`	Returns this prefix as a start bound.
`default java.nio.ByteBuffer`	`bufferAt(int i)`
`default java.lang.String`	`clusteringString(java.util.List<AbstractType<?>> types)`	Produce a human-readable representation of the clustering given the list of types.
`default int`	`dataSize()`	The size of the data hold by this prefix.
`default void`	`digest(Digest digest)`	Adds the data of this clustering prefix to the provided Digest instance.
`static boolean`	`equals(ClusteringPrefix<?> prefix, java.lang.Object o)`
`static <V1,V2> boolean`	`equals(ClusteringPrefix<V1> left, ClusteringPrefix<V2> right)`
`V`	`get(int i)`	Retrieves the ith value of this prefix.
`java.nio.ByteBuffer[]`	`getBufferArray()`
`V[]`	`getRawValues()`	The values of this prefix as an array.
`static <V> int`	`hashCode(ClusteringPrefix<V> prefix)`
`default boolean`	`isBottom()`
`default boolean`	`isEmpty()`
`default boolean`	`isTop()`
`ClusteringPrefix.Kind`	`kind()`
`ClusteringPrefix<V>`	`retainable()`	Return the key in a form that can be retained for longer-term use.
`default java.nio.ByteBuffer`	`serializeAsPartitionKey()`
`int`	`size()`	The number of values in this prefix.
`default java.lang.String`	`stringAt(int i, ClusteringComparator comparator)`
`java.lang.String`	`toString(TableMetadata metadata)`	Generates a proper string representation of the prefix.
`default void`	`validate()`
`default void`	`validate(int i, ClusteringComparator comparator)`

Methods inherited from interface org.apache.cassandra.db.Clusterable
clustering

Methods inherited from interface org.apache.cassandra.cache.IMeasurableMemory
unsharedHeapSize

- Field Detail
  - serializer
```
static final ClusteringPrefix.Serializer serializer
```
- Method Detail
  - isBottom
```
default boolean isBottom()
```
  - isTop
```
default boolean isTop()
```
  - kind
```
ClusteringPrefix.Kind kind()
```
  - size
```
int size()
```
    The number of values in this prefix. There can't be more values that the this is a prefix of has of clustering columns.
    
    Returns:
    
    the number of values in this prefix.
  - isEmpty
```
default boolean isEmpty()
```
  - get
```
V get(int i)
```
    Retrieves the ith value of this prefix.
    
    Parameters:
    
    i - the index of the value to retrieve. Must be such that 0 <= i < size().
    
    Returns:
    
    the ith value of this prefix. Note that a value can be null.
  - accessor
```
ValueAccessor<V> accessor()
```
  - bufferAt
```
default java.nio.ByteBuffer bufferAt(int i)
```
  - stringAt
```
default java.lang.String stringAt(int i,
                                  ClusteringComparator comparator)
```
  - validate
```
default void validate()
```
  - validate
```
default void validate(int i,
                      ClusteringComparator comparator)
```
  - digest
```
default void digest(Digest digest)
```
    Adds the data of this clustering prefix to the provided Digest instance.
    
    Parameters:
    
    digest - the Digest instance to which to add this prefix.
  - dataSize
```
default int dataSize()
```
    The size of the data hold by this prefix.
    
    Returns:
    
    the size of the data hold by this prefix (this is not the size of the object in memory, just the size of the data it stores).
  - toString
```
java.lang.String toString(TableMetadata metadata)
```
    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.
  - asStartBound
```
ClusteringBound<V> asStartBound()
```
    Returns this prefix as a start bound. If this prefix is a bound, just returns it asserting that it is a start bound. If this prefix is a clustering, returns an included start bound. If this prefix is a boundary, returns an open bound of it
  - asEndBound
```
ClusteringBound<V> asEndBound()
```
    Returns this prefix as an end bound. If this prefix is a bound, just returns it asserting that it is an end bound. If this prefix is a clustering, returns an included end bound. In this prefix is a boundary, returns a close bound of it.
  - serializeAsPartitionKey
```
default java.nio.ByteBuffer serializeAsPartitionKey()
```
  - clusteringString
```
default java.lang.String clusteringString(java.util.List<AbstractType<?>> types)
```
    Produce a human-readable representation of the clustering given the list of types. Easier to access than metadata for debugging.
  - getRawValues
```
V[] getRawValues()
```
    The values of this prefix as an array.
    Please note that this may or may not require an array creation. So 1) you should *not* modify the returned array and 2) it's more efficient to use size() and get(int) unless you actually need an array.
    
    Returns:
    
    the values for this prefix as an array.
  - getBufferArray
```
java.nio.ByteBuffer[] getBufferArray()
```
  - retainable
```
ClusteringPrefix<V> retainable()
```
    Return the key in a form that can be retained for longer-term use. This means extracting keys stored in shared memory (i.e. in memtables) to minimized on-heap versions. If the object is already in minimal form, no action will be taken.
  - hashCode
```
static <V> int hashCode(ClusteringPrefix<V> prefix)
```
  - equals
```
static <V1,V2> boolean equals(ClusteringPrefix<V1> left,
                                    ClusteringPrefix<V2> right)
```
  - equals
```
static boolean equals(ClusteringPrefix<?> prefix,
                      java.lang.Object o)
```

Interface ClusteringPrefix<V>

Nested Class Summary

Field Summary

Method Summary

Methods inherited from interface org.apache.cassandra.db.Clusterable

Methods inherited from interface org.apache.cassandra.cache.IMeasurableMemory

Field Detail

serializer

Method Detail

isBottom

isTop

kind

size

isEmpty

get

accessor

bufferAt

stringAt

validate

validate

digest

dataSize

toString

asStartBound

asEndBound

serializeAsPartitionKey

clusteringString

getRawValues

getBufferArray

retainable

hashCode

equals

equals