GitHub user dalaro opened a pull request:
https://github.com/apache/tinkerpop/pull/372
DSP-1397 Fix StarGraph addEdge for self-edges
StarGraph has directionally-specific classes for its edges:
* StarInEdge
* StarOutEdge
StarIn(/Out)Edges belong only in a StarVertex's in(/out)Edges map. We
see this assumption in StarVertex.applyGraphFilter, which invokes
`graphFilter.legalEdges(this)` and then invokes `instanceof
StarOutEdge` on each legal edge to determine its direction.
This assumption was violated by the StarVertex.addEdge method. This
method special-cases self-edge addition. This method first
unconditionally adds a StarOutEdge. Then, it checks to see whether
its parameters indicate that it is adding a self-edge. If this is so,
the method proceeds to add that same StarOutEdge instance to the
inEdges map. This is the problem. Adding a self-edge to a StarVertex
results in one StarOutEdge instance that belongs to both the inEdges
and outEdges map, which later causes the `applyGraphFilter` method's
`instanceof` checks to yield two out edges and no in edges on a
self-loop.
This commit changes StarVertex so that self-edges are represented
by a new class, StarSelfEdge.
You can merge this pull request into a Git repository by running:
$ git pull https://github.com/dalaro/incubator-tinkerpop DSP-1397
Alternatively you can review and apply these changes as the patch at:
https://github.com/apache/tinkerpop/pull/372.patch
To close this pull request, make a commit to your master/trunk branch
with (at least) the following in the commit message:
This closes #372
----
commit dddc44369e2c645a854b2a7bed0f4af51acd6fc5
Author: Dan LaRocque <[email protected]>
Date: 2016-08-04T04:41:44Z
DSP-1397 Fix StarGraph addEdge for self-edges
StarGraph has directionally-specific classes for its edges:
* StarInEdge
* StarOutEdge
StarIn(/Out)Edges belong only in a StarVertex's in(/out)Edges map. We
see this assumption in StarVertex.applyGraphFilter, which invokes
`graphFilter.legalEdges(this)` and then invokes `instanceof
StarOutEdge` on each legal edge to determine its direction.
This assumption was violated by the StarVertex.addEdge method. This
method special-cases self-edge addition. This method first
unconditionally adds a StarOutEdge. Then, it checks to see whether
its parameters indicate that it is adding a self-edge. If this is so,
the method proceeds to add that same StarOutEdge instance to the
inEdges map. This is the problem. Adding a self-edge to a StarVertex
results in one StarOutEdge instance that belongs to both the inEdges
and outEdges map, which later causes the `applyGraphFilter` method's
`instanceof` checks to yield two out edges and no in edges on a
self-loop.
----
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