public Iterable<LongWritable> getPartitionDestinationVertices(
int partitionId) {
Long2DoubleOpenHashMap partitionMap = map.get(partitionId);
List<LongWritable> vertices =
Lists.newArrayListWithCapacity(partitionMap.size());
LongIterator iterator = partitionMap.keySet().iterator();
while (iterator.hasNext()) {
vertices.add(new LongWritable(iterator.nextLong()));
}
return vertices;
}