@Override
public Iterator<Edge> edges(final Object... edgeIds) {
try {
if (0 == edgeIds.length) {
return new HadoopEdgeIterator(this);
} else {
// base the conversion function on the first item in the id list as the expectation is that
// these
// id values will be a uniform list
if (edgeIds[0] instanceof Edge) {
// based on the first item assume all Edges in the argument list
if (!Stream.of(edgeIds).allMatch(id -> id instanceof Edge))
throw Graph.Exceptions.idArgsMustBeEitherIdOrElement();
// no need to get the vertices again, so just flip it back - some implementation may want
// to treat this
// as a refresh operation. that's not necessary for hadoopgraph.
return Stream.of(edgeIds).map(id -> (Edge) id).iterator();
} else {
final Class<?> firstClass = edgeIds[0].getClass();
if (!Stream.of(edgeIds).map(Object::getClass).allMatch(firstClass::equals))
throw Graph.Exceptions
.idArgsMustBeEitherIdOrElement(); // todo: change exception to be ids of the same
// type
return IteratorUtils.filter(
new HadoopEdgeIterator(this), vertex -> ElementHelper.idExists(vertex.id(), edgeIds));
}
}
} catch (final IOException e) {
throw new IllegalStateException(e.getMessage(), e);
}
}
@Override
public <C extends GraphComputer> C compute(final Class<C> graphComputerClass) {
if (graphComputerClass.equals(GiraphGraphComputer.class))
return (C) new GiraphGraphComputer(this);
else if (graphComputerClass.equals(SparkGraphComputer.class))
return (C) new SparkGraphComputer(this);
else throw Graph.Exceptions.graphDoesNotSupportProvidedGraphComputer(graphComputerClass);
}