com.bigdata.rdf.rules
Class AbstractRuleDistinctTermScan

java.lang.Object
  com.bigdata.relation.rule.Rule
      com.bigdata.rdf.rules.AbstractRuleDistinctTermScan

All Implemented Interfaces:

IRule, IStep, Serializable

Direct Known Subclasses:

RuleRdf01, RuleRdfs04a, RuleRdfs04b

public abstract class AbstractRuleDistinctTermScan
extends Rule

Base class for rules having a single predicate that is none bound in the tail and a single variable in the head. These rules can be evaluated using SPOAccessPath#distinctTermScan() rather than a full index scan. For example:

  rdf1:   (?u ?a ?y) -> (?a rdf:type rdf:Property)
  rdfs4a: (?u ?a ?x) -> (?u rdf:type rdfs:Resource)
  rdfs4b: (?u ?a ?v) -> (?v rdf:type rdfs:Resource)
 

Version:

$Id: AbstractRuleDistinctTermScan.java 2265 2009-10-26 12:51:06Z thompsonbry $

Author:

Bryan Thompson

See Also:

Serialized Form

Nested Class Summary

protected static class

AbstractRuleDistinctTermScan.DistinctTermScan Selects the distinct term identifiers, substituting their binding in the sole unbound variable in the head of the rule.

Field Summary

Fields inherited from class com.bigdata.relation.rule.Rule

DEBUG, INFO, log

Constructor Summary

AbstractRuleDistinctTermScan(String name, SPOPredicate head, SPOPredicate[] body, IConstraint[] constraints)

Method Summary

IRuleTaskFactory

getTaskFactory() An optional IRuleTaskFactory that will be used in place of the default IRuleTaskFactory to evaluate this rule (optional)

Methods inherited from class com.bigdata.relation.rule.Rule

getConstants, getConstraint, getConstraintCount, getConstraints, getHead, getName, getQueryOptions, getSharedVars, getSharedVars, getTail, getTail, getTailCount, getVariableCount, getVariableCount, getVariables, isConsistent, isDeclared, isFullyBound, isFullyBound, isRule, specialize, specialize, toString, toString, var

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

AbstractRuleDistinctTermScan

public AbstractRuleDistinctTermScan(String name,
                                    SPOPredicate head,
                                    SPOPredicate[] body,
                                    IConstraint[] constraints)

Method Detail

getTaskFactory

public IRuleTaskFactory getTaskFactory()

Description copied from interface: IRule

An optional IRuleTaskFactory that will be used in place of the default IRuleTaskFactory to evaluate this rule (optional)

Specified by:

getTaskFactory in interface IRule

Overrides:

getTaskFactory in class Rule

Returns:

null unless custom evaluation is desired.