org.modeshape.jcr.spi.index.provider

Interface Costable

All Known Subinterfaces:

LocalIndex<T>, ManagedIndex

All Known Implementing Classes:

ManagedLocalIndex

public interface Costable

A simple interface that provides metrics needed to compute the cost of applying indexes.

Method Summary

Methods

Modifier and Type	Method and Description
long	estimateCardinality(Constraint constraint, Map<String,Object> variables) Compute the cost applying the given constraint.
long	estimateTotalCount() Get the estimated number of entries within this index.

Method Detail

estimateCardinality

long estimateCardinality(Constraint constraint,
                       Map<String,Object> variables)

Compute the cost applying the given constraint.

Parameters:

constraint - the constraint; never null

variables - the bound variables for the query that is being costed; never null

Returns:

the approximate number of records that will be returned

estimateTotalCount

long estimateTotalCount()

Get the estimated number of entries within this index.

Returns:

the number of entries, or -1 if not known