org.apache.cassandra.db.context

Interface IContext

All Known Implementing Classes:

CounterContext

public interface IContext

An opaque commutative context. Maintains a ByteBuffer context that represents a partitioned commutative value.

Nested Class Summary

Nested Classes

Modifier and Type	Interface and Description
static class	IContext.ContextRelationship

Method Summary

Methods

Modifier and Type	Method and Description
IContext.ContextRelationship	diff(java.nio.ByteBuffer left, java.nio.ByteBuffer right) Determine the relationship between two contexts.
java.nio.ByteBuffer	merge(java.nio.ByteBuffer left, java.nio.ByteBuffer right, Allocator allocator) Return a context w/ an aggregated count for each node id.
java.lang.String	toString(java.nio.ByteBuffer context) Human-readable String from context.

Method Detail

diff

IContext.ContextRelationship diff(java.nio.ByteBuffer left,
                                java.nio.ByteBuffer right)

Determine the relationship between two contexts. EQUAL: Equal set of nodes and every count is equal. GREATER_THAN: Superset of nodes and every count is equal or greater than its corollary. LESS_THAN: Subset of nodes and every count is equal or less than its corollary. DISJOINT: Node sets are not equal and/or counts are not all greater or less than.

Parameters:

left - context.

right - context.

Returns:

the ContextRelationship between the contexts.

merge

java.nio.ByteBuffer merge(java.nio.ByteBuffer left,
                        java.nio.ByteBuffer right,
                        Allocator allocator)

Return a context w/ an aggregated count for each node id.

Parameters:

left - context.

right - context.

allocator - an allocator to allocate the new context from.

toString

java.lang.String toString(java.nio.ByteBuffer context)

Human-readable String from context.

Parameters:

context - context.

Returns:

a human-readable String of the context.