org.jrdf.query.relation.operation.mem.common
Class RelationProcessorImpl

java.lang.Object
  org.jrdf.query.relation.operation.mem.common.RelationProcessorImpl

All Implemented Interfaces:

RelationProcessor

public final class RelationProcessorImpl
extends Object
implements RelationProcessor

Common tuple processing code - gets headings and then processes tuples using the tuple engine.

Constructor Summary

RelationProcessorImpl(RelationFactory relationFactory, TupleComparator tupleComparator)

Method Summary

Relation	convertToConstants(Relation resultRelation) Converts a relation with no heading and no tuples to false (TABLE_DUM) and a relation with no heading but some tuples to true (TABLE_DEE).
Relation	processRelations(Set<Relation> relations, TupleEngine tupleEngine) A set of relations that are to be processed by the tuple engine.

Methods inherited from class java.lang.Object

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

Constructor Detail

RelationProcessorImpl

public RelationProcessorImpl(RelationFactory relationFactory,
                             TupleComparator tupleComparator)

Method Detail

processRelations

public Relation processRelations(Set<Relation> relations,
                                 TupleEngine tupleEngine)

Description copied from interface: RelationProcessor

A set of relations that are to be processed by the tuple engine. First headings are processed and then the bodies of the relations.

Specified by:

processRelations in interface RelationProcessor

Parameters:

relations - the relations to be processed by the tuple engine.

tupleEngine - the engine.

Returns:

the result of calling the tuple engine with all relations given as input.

convertToConstants

public Relation convertToConstants(Relation resultRelation)

Description copied from interface: RelationProcessor

Converts a relation with no heading and no tuples to false (TABLE_DUM) and a relation with no heading but some tuples to true (TABLE_DEE).

Specified by:

convertToConstants in interface RelationProcessor

Parameters:

resultRelation - the relation to convert.

Returns:

either TABLE_DUM (false), TABLE_DEE (true) or the same relation.