it.unibz.inf.ontop.datalog.impl

Class UnionFlattenerImpl

java.lang.Object

it.unibz.inf.ontop.datalog.impl.UnionFlattenerImpl

All Implemented Interfaces:

UnionFlattener, IQOptimizer

public class UnionFlattenerImpl
extends Object
implements UnionFlattener

Lifts unions above projections, until a fixed point is reached. Also merges consecutive unions and projections.

This normalization may be needed for datalog-based mapping optimizers.

Method Summary

Modifier and Type	Method and Description
IQ	optimize(IQ query) TODO: why a fix point?
IQTree	optimize(IQTree tree, VariableGenerator variableGenerator)

Methods inherited from class java.lang.Object

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

Method Detail

optimize

public IQ optimize(IQ query)

TODO: why a fix point?

Specified by:

optimize in interface UnionFlattener

Specified by:

optimize in interface IQOptimizer

optimize

public IQTree optimize(IQTree tree,
                       VariableGenerator variableGenerator)

Specified by:

optimize in interface UnionFlattener