Change cast to Vertex used in prepareSuperstep() to BasicVertex
---------------------------------------------------------------
Key: GIRAPH-113
URL: https://issues.apache.org/jira/browse/GIRAPH-113
Project: Giraph
Issue Type: Bug
Reporter: Yuanyuan Tian
Priority: Minor
Hi,
I decided to use LongDoubleFloatDoubleVertex in a graph algorithm because it
uses more compact and efficient mahout collections. However I run into an error
when running the algorithm:
java.lang.ClassCastException:
org.apache.giraph.graph.LongDoubleFloatDoubleVertex cannot be cast to
org.apache.giraph.graph.Vertex
at
org.apache.giraph.comm.BasicRPCCommunications.prepareSuperstep(BasicRPCCommunications.java:1016)
at
org.apache.giraph.graph.BspServiceWorker.startSuperstep(BspServiceWorker.java:843)
at org.apache.giraph.graph.GraphMapper.map(GraphMapper.java:569)
at org.apache.giraph.graph.GraphMapper.run(GraphMapper.java:728)
... 7 more
Basically, the problem is that in BasicRPCCommunications.prepareSuperStep(),
the LongDoubleFloatDoubleVertex are cast to Vertex in the following code
fragment. But LongDoubleFloatDoubleVertex inherits from BasicVertex instead of
Vertex.
if (vertex != null) {
((MutableVertex<I, V, E, M>) vertex).setVertexId(vertexIndex);
partition.putVertex((Vertex<I, V, E, M>) vertex);
} else if (originalVertex != null) {
partition.removeVertex(originalVertex.getVertexId());
}
I did a simple change: cast LongDoubleFloatDoubleVertex to BasicVertex. The
problem went away, and the algorithm finished without any error. But I am not
sure this change has any implication to other parts of the code. So, I hope to
get some comments from the Giraph developers.
if (vertex != null) {
((MutableVertex<I, V, E, M>) vertex).setVertexId(vertexIndex);
partition.putVertex((BasicVertex<I, V, E, M>) vertex);
} else if (originalVertex != null) {
partition.removeVertex(originalVertex.getVertexId());
}
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