Class FlattenSingletonUnionsTransform

java.lang.Object

org.eclipse.rdf4j.queryrender.sparql.ir.util.transform.BaseTransform

org.eclipse.rdf4j.queryrender.sparql.ir.util.transform.FlattenSingletonUnionsTransform

public final class FlattenSingletonUnionsTransform
extends BaseTransform

Remove UNION nodes that have a single branch, effectively inlining their content. This keeps the IR compact and avoids printing unnecessary braces/UNION keywords. Safety: - Does not flatten inside OPTIONAL bodies to avoid subtle scope/precedence shifts when later transforms reorder filters and optionals. - Preserves explicit UNIONs with new variable scope (not constructed by transforms), even if they degenerate to a single branch, to respect original user structure.

Field Summary

Fields inherited from class BaseTransform

ANON_PATH_INVERSE_PREFIX, ANON_PATH_PREFIX

Method Summary

Modifier and Type	Method	Description
static IrBGP	apply(IrBGP bgp)

Methods inherited from class BaseTransform

bgpWithLines, branchHasAnonPathBridge, copyAllExcept, fuseAdjacentPtThenPt, fuseAdjacentSpThenPt, fuseAltInverseTailBGP, fusePtSpPtSequence, invertNegatedPropertySet, iri, isAnonPathInverseVar, isAnonPathVar, isConstantIriPredicate, joinPathWithLaterSp, mergeNpsMembers, normalizeCompactNps, orientBareNpsForNext, rewriteContainers, sameVar, sameVarOrValue, unionBranchesAllHaveAnonPathBridge, unionBranchesShareAnonPathVarWithAllowedRoleMapping, unionBranchesShareCommonAnonPathVarName, unionIsExplicitAndAllBranchesScoped, varOrValue

Methods inherited from class Object

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

Method Details

apply

public static IrBGP apply(IrBGP bgp)