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Posted to dev@tinkerpop.apache.org by "Stephen Mallette (Jira)" <ji...@apache.org> on 2021/01/26 14:51:00 UTC
[jira] [Updated] (TINKERPOP-2510) by-modulator throws when token is
used after elementMap()
[ https://issues.apache.org/jira/browse/TINKERPOP-2510?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Stephen Mallette updated TINKERPOP-2510:
----------------------------------------
Component/s: process
> by-modulator throws when token is used after elementMap()
> ---------------------------------------------------------
>
> Key: TINKERPOP-2510
> URL: https://issues.apache.org/jira/browse/TINKERPOP-2510
> Project: TinkerPop
> Issue Type: Bug
> Components: process
> Affects Versions: 3.4.9
> Reporter: Christopher Smith
> Priority: Major
>
> I'm attempting to write a "join" traversal to return the values of several related vertices (of different types), starting from an entry vertex. In order to extract the relevant properties, I am currently using {{elementMap}}, then trying to stash the vertex properties to continue with my query:
> {code:groovy}
> gts.V(entryPoint).as('p')
> .sideEffect(__.elementMap().group('pp').by(T.id))
> .out...
> ...
> .select('pp', ...)
> {code}
> As {{elementMap}} produces a map that includes the tokens as map keys, I expected {{by(T.id)}} to extract a map keyed on the vertex ID with the properties as the value (right now folded, but I'm crunching on that later). Using strings like {{'firstName'}} works as expected, but of course using the string {{'id'}} does not because the map key is the token, not the string.
> However, passing {{T.id}} to the by-modulator when the value is a map (instead of an element) produces a {{ClassCastException}}. As far as I can tell, the processor is assuming somewhere that {{by(T.id)}} indicates that the incoming value is an element, which (at least after the addition of {{elementMap}}) is not true.
> {code}
> java.lang.ClassCastException: class java.util.LinkedHashMap cannot be cast to class org.apache.tinkerpop.gremlin.structure.Element (java.util.LinkedHashMap is in module java.base of loader 'bootstrap'; org.apache.tinkerpop.gremlin.structure.Element is in unnamed module of loader 'app')
> at org.apache.tinkerpop.gremlin.process.traversal.lambda.TokenTraversal.addStart(TokenTraversal.java:46)
> at org.apache.tinkerpop.gremlin.process.traversal.util.TraversalUtil.apply(TraversalUtil.java:42)
> at org.apache.tinkerpop.gremlin.process.traversal.util.TraversalUtil.applyNullable(TraversalUtil.java:87)
> at org.apache.tinkerpop.gremlin.process.traversal.step.sideEffect.GroupSideEffectStep.sideEffect(GroupSideEffectStep.java:114)
> at org.apache.tinkerpop.gremlin.process.traversal.step.sideEffect.SideEffectStep.processNextStart(SideEffectStep.java:39)
> at org.apache.tinkerpop.gremlin.process.traversal.step.util.AbstractStep.hasNext(AbstractStep.java:143)
> at org.apache.tinkerpop.gremlin.process.traversal.util.DefaultTraversal.hasNext(DefaultTraversal.java:197)
> at org.apache.tinkerpop.gremlin.process.traversal.step.sideEffect.TraversalSideEffectStep.sideEffect(TraversalSideEffectStep.java:48)
> at org.apache.tinkerpop.gremlin.process.traversal.step.sideEffect.SideEffectStep.processNextStart(SideEffectStep.java:39)
> at org.apache.tinkerpop.gremlin.process.traversal.step.util.AbstractStep.hasNext(AbstractStep.java:143)
> at org.apache.tinkerpop.gremlin.process.traversal.step.util.ExpandableStepIterator.next(ExpandableStepIterator.java:50)
> at org.apache.tinkerpop.gremlin.process.traversal.step.map.FlatMapStep.processNextStart(FlatMapStep.java:48)
> at org.apache.tinkerpop.gremlin.process.traversal.step.util.AbstractStep.hasNext(AbstractStep.java:143)
> at org.apache.tinkerpop.gremlin.process.traversal.step.util.ExpandableStepIterator.next(ExpandableStepIterator.java:50)
> at org.apache.tinkerpop.gremlin.process.traversal.step.filter.FilterStep.processNextStart(FilterStep.java:37)
> at org.apache.tinkerpop.gremlin.process.traversal.step.util.AbstractStep.hasNext(AbstractStep.java:143)
> at org.apache.tinkerpop.gremlin.process.traversal.step.util.ExpandableStepIterator.next(ExpandableStepIterator.java:50)
> at org.apache.tinkerpop.gremlin.process.traversal.step.map.FlatMapStep.processNextStart(FlatMapStep.java:48)
> at org.apache.tinkerpop.gremlin.process.traversal.step.util.AbstractStep.hasNext(AbstractStep.java:143)
> at org.apache.tinkerpop.gremlin.process.traversal.step.util.ExpandableStepIterator.next(ExpandableStepIterator.java:50)
> at org.apache.tinkerpop.gremlin.process.traversal.step.map.FlatMapStep.processNextStart(FlatMapStep.java:48)
> at org.apache.tinkerpop.gremlin.process.traversal.step.util.AbstractStep.hasNext(AbstractStep.java:143)
> at org.apache.tinkerpop.gremlin.process.traversal.step.util.ExpandableStepIterator.next(ExpandableStepIterator.java:50)
> at org.apache.tinkerpop.gremlin.process.traversal.step.filter.FilterStep.processNextStart(FilterStep.java:37)
> at org.apache.tinkerpop.gremlin.process.traversal.step.util.AbstractStep.hasNext(AbstractStep.java:143)
> at org.apache.tinkerpop.gremlin.process.traversal.step.util.ExpandableStepIterator.next(ExpandableStepIterator.java:50)
> at org.apache.tinkerpop.gremlin.process.traversal.step.map.FlatMapStep.processNextStart(FlatMapStep.java:48)
> at org.apache.tinkerpop.gremlin.process.traversal.step.util.AbstractStep.hasNext(AbstractStep.java:143)
> at org.apache.tinkerpop.gremlin.process.traversal.step.util.ExpandableStepIterator.next(ExpandableStepIterator.java:50)
> at org.apache.tinkerpop.gremlin.process.traversal.step.map.MapStep.processNextStart(MapStep.java:36)
> at org.apache.tinkerpop.gremlin.process.traversal.step.map.SelectOneStep.processNextStart(SelectOneStep.java:131)
> at org.apache.tinkerpop.gremlin.process.traversal.step.util.AbstractStep.next(AbstractStep.java:128)
> at org.apache.tinkerpop.gremlin.process.traversal.step.util.AbstractStep.next(AbstractStep.java:38)
> at org.apache.tinkerpop.gremlin.process.traversal.util.DefaultTraversal.next(DefaultTraversal.java:205)
> at com.example.Queries.query(Queries.groovy:39)
> {code}
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