org.aksw.limes.core.execution.rewriter

Class AlgebraicRewriter

java.lang.Object

org.aksw.limes.core.execution.rewriter.Rewriter

org.aksw.limes.core.execution.rewriter.AlgebraicRewriter

All Implemented Interfaces:

IRewriter

public class AlgebraicRewriter
extends Rewriter

Implements the algebraic rewriter class. The idea is that the rewriter gets as input a link specification returns an equivalent yet probably more time-efficient link specification.

Version:

1.0

Author:

Axel-C. Ngonga Ngomo (ngonga@informatik.uni-leipzig.de)

Constructor Summary

Constructors

Constructor and Description
AlgebraicRewriter()

Method Summary

Modifier and Type	Method and Description
LinkSpecification	collapseSpec(LinkSpecification spec) Collapses a spec by making use of the dependencies within the specification.
LinkSpecification	computeAllDependencies(LinkSpecification spec) Updates all dependencies within a specification.
LinkSpecification	computeAtomicDependencies(LinkSpecification spec) Computes all atomic dependencies within a link specification.
LinkSpecification	computeAtomicDependency(LinkSpecification source, LinkSpecification target) Checks whether source depends on target, i.e., whether the mapping generated by source is a subset of the mapping generated by target.
LinkSpecification	computeNonAtomicDependencies(LinkSpecification spec) Updates the non-atomic dependencies of a link specification.
String	getMeasure(LinkSpecification spec) Returns the measure used in the specification.
List<String>	getProperties(LinkSpecification spec) Returns the properties that are used for the comparison.
LinkSpecification	removeDuplicates(LinkSpecification spec) Removes duplicated specifications from specification.
LinkSpecification	removeUnaryOperators(LinkSpecification spec) Removes unary operators from a specification.
LinkSpecification	rewrite(LinkSpecification spec) Rewrites a Link Specification.
LinkSpecification	updateThresholds(LinkSpecification spec) Updates the thresholds within the input link specification.

Methods inherited from class java.lang.Object

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

Constructor Detail

AlgebraicRewriter

public AlgebraicRewriter()

Method Detail

rewrite

public LinkSpecification rewrite(LinkSpecification spec)

Rewrites a Link Specification. The idea is that the rewriter gets as input a link specification returns an equivalent yet probably more time-efficient link specification.

Parameters:

spec, - Input link specification

Returns:

the input link specification.

updateThresholds

public LinkSpecification updateThresholds(LinkSpecification spec)

Updates the thresholds within the input link specification.

Parameters:

spec, - The input link specification

Returns:

Return spec with updated weights

removeDuplicates

public LinkSpecification removeDuplicates(LinkSpecification spec)

Removes duplicated specifications from specification.

Parameters:

spec, - The input link specification

Returns:

spec, de-duplicated specification

removeUnaryOperators

public LinkSpecification removeUnaryOperators(LinkSpecification spec)

Removes unary operators from a specification.

Parameters:

spec, - The input link specification

Returns:

Cleaned up spec

computeAtomicDependency

public LinkSpecification computeAtomicDependency(LinkSpecification source,
                                                 LinkSpecification target)

Checks whether source depends on target, i.e., whether the mapping generated by source is a subset of the mapping generated by target. Returns 0 if no dependency is found, 1 if target is included in source, -1 if source is included in target and +2 if they are equivalent.

Parameters:

source - Source link spec

target - Target link spec

Returns:

-1, 0, +1 or +2

getProperties

public List<String> getProperties(LinkSpecification spec)

Returns the properties that are used for the comparison. Only works for atomic specifications.

Parameters:

spec, - The input specification

Returns:

List of properties used in the specification

getMeasure

public String getMeasure(LinkSpecification spec)

Returns the measure used in the specification.

Parameters:

spec, - The input specification

Returns:

Measure used in the specification, null if the specification is not atomic

computeAllDependencies

public LinkSpecification computeAllDependencies(LinkSpecification spec)

Updates all dependencies within a specification.

Parameters:

spec, - The input specification

Returns:

spec, with all dependencies updated

computeNonAtomicDependencies

public LinkSpecification computeNonAtomicDependencies(LinkSpecification spec)

Updates the non-atomic dependencies of a link specification.

Parameters:

spec, - The input specification

Returns:

spec, updated specification with non-atomic dependencies

computeAtomicDependencies

public LinkSpecification computeAtomicDependencies(LinkSpecification spec)

Computes all atomic dependencies within a link specification.

Parameters:

spec, - The input specification

Returns:

spec, updated specification with atomic dependencies

collapseSpec

public LinkSpecification collapseSpec(LinkSpecification spec)

Collapses a spec by making use of the dependencies within the specification.

Parameters:

spec, - The input specification

Returns:

Collapsed spec, i.e., specification where dependencies have been removed