package com.thinkaurelius.faunus.mapreduce.transform;
import com.thinkaurelius.faunus.FaunusEdge;
import com.thinkaurelius.faunus.FaunusElement;
import com.thinkaurelius.faunus.FaunusVertex;
import com.thinkaurelius.faunus.Tokens;
import com.thinkaurelius.faunus.mapreduce.FaunusCompiler;
import com.thinkaurelius.faunus.mapreduce.util.EmptyConfiguration;
import com.thinkaurelius.faunus.mapreduce.util.SafeMapperOutputs;
import com.tinkerpop.blueprints.Direction;
import com.tinkerpop.blueprints.Edge;
import com.tinkerpop.blueprints.Element;
import com.tinkerpop.blueprints.Vertex;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.io.NullWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapreduce.Mapper;
import java.io.IOException;
import java.util.List;
/**
* @author Marko A. Rodriguez (http://markorodriguez.com)
*/
public class PathMap {
public static final String CLASS = Tokens.makeNamespace(PathMap.class) + ".class";
public enum Counters {
VERTICES_PROCESSED,
OUT_EDGES_PROCESSED
}
public static Configuration createConfiguration(final Class<? extends Element> klass) {
final Configuration configuration = new EmptyConfiguration();
configuration.setClass(CLASS, klass, Element.class);
configuration.setBoolean(FaunusCompiler.PATH_ENABLED, true);
return configuration;
}
public static class Map extends Mapper<NullWritable, FaunusVertex, NullWritable, Text> {
private boolean isVertex;
private final Text textWritable = new Text();
private SafeMapperOutputs outputs;
@Override
public void setup(final Mapper.Context context) throws IOException, InterruptedException {
this.isVertex = context.getConfiguration().getClass(CLASS, Element.class, Element.class).equals(Vertex.class);
this.outputs = new SafeMapperOutputs(context);
if (!context.getConfiguration().getBoolean(FaunusCompiler.PATH_ENABLED, false))
throw new IllegalStateException(PathMap.class.getSimpleName() + " requires that paths be enabled");
}
@Override
public void map(final NullWritable key, final FaunusVertex value, final Mapper<NullWritable, FaunusVertex, NullWritable, Text>.Context context) throws IOException, InterruptedException {
if (this.isVertex && value.hasPaths()) {
for (final List<FaunusElement.MicroElement> path : value.getPaths()) {
this.textWritable.set(path.toString());
this.outputs.write(Tokens.SIDEEFFECT, NullWritable.get(), this.textWritable);
}
context.getCounter(Counters.VERTICES_PROCESSED).increment(1l);
} else {
long edgesProcessed = 0;
for (final Edge e : value.getEdges(Direction.OUT)) {
final FaunusEdge edge = (FaunusEdge) e;
if (edge.hasPaths()) {
for (final List<FaunusElement.MicroElement> path : edge.getPaths()) {
this.textWritable.set(path.toString());
this.outputs.write(Tokens.SIDEEFFECT, NullWritable.get(), this.textWritable);
}
edgesProcessed++;
}
}
context.getCounter(Counters.OUT_EDGES_PROCESSED).increment(edgesProcessed);
}
this.outputs.write(Tokens.GRAPH, NullWritable.get(), value);
}
@Override
public void cleanup(final Mapper<NullWritable, FaunusVertex, NullWritable, Text>.Context context) throws IOException, InterruptedException {
this.outputs.close();
}
}
}