org.openanzo.glitter
Class DefaultEngineConfig

java.lang.Object
  org.openanzo.glitter.DefaultEngineConfig

All Implemented Interfaces:

EngineConfig

Direct Known Subclasses:

CoreEngineConfig, LdapEngineConfig

public abstract class DefaultEngineConfig
extends java.lang.Object
implements EngineConfig

Base class for Glitter EngineConfig implementations. Provides a base configuration that allows N-ary union, does substitute fixed bindings, and rewrites query trees to with the ConjunctiveRewriter and the NormalFormRewriter.

Author:

lee

Constructor Summary

DefaultEngineConfig()

Method Summary

boolean	allowNaryUnion()
java.lang.Iterable<TreeRewriter>	getTreeRewriters()
boolean	substituteFixedBindings() In many cases, an intermediate result set contains solutions that all bind a given variable to the same value.

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface org.openanzo.glitter.EngineConfig

getDatasetClass, getFunctionalPredicates, getQueryExecutionPlan, getQueryValidators, getSolutionGeneratorFactory, includeInferredTriples

Constructor Detail

DefaultEngineConfig

public DefaultEngineConfig()

Method Detail

allowNaryUnion

public boolean allowNaryUnion()

Specified by:

allowNaryUnion in interface EngineConfig

Returns:

Whether the normal form rewriter should combine nested binary UNIONs into a single N-ary UNION operator.

getTreeRewriters

public java.lang.Iterable<TreeRewriter> getTreeRewriters()

Specified by:

getTreeRewriters in interface EngineConfig

Returns:

An enumeration of TreeRewriters that will be applied sequentially to transform the SPARQL query tree before query execution.

substituteFixedBindings

public boolean substituteFixedBindings()

Description copied from interface: EngineConfig

In many cases, an intermediate result set contains solutions that all bind a given variable to the same value. In most cases, this value can be safely substituted in for the variable anywhere else in the query that the variable appears.

Specified by:

substituteFixedBindings in interface EngineConfig

Returns:

Whether the engine should aggressively substitute for variables with fixed values.