package com.thinkaurelius.faunus.mapreduce.transform;
import com.thinkaurelius.faunus.FaunusEdge;
import com.thinkaurelius.faunus.FaunusVertex;
import com.thinkaurelius.faunus.Tokens;
import com.thinkaurelius.faunus.mapreduce.util.ElementPicker;
import com.thinkaurelius.faunus.mapreduce.util.EmptyConfiguration;
import com.thinkaurelius.faunus.mapreduce.util.SafeMapperOutputs;
import com.thinkaurelius.faunus.mapreduce.util.WritableHandler;
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.io.WritableComparable;
import org.apache.hadoop.mapreduce.Mapper;
import java.io.IOException;
/**
* @author Marko A. Rodriguez (http://markorodriguez.com)
*/
public class PropertyMap {
public static final String CLASS = Tokens.makeNamespace(PropertyMap.class) + ".class";
public static final String KEY = Tokens.makeNamespace(PropertyMap.class) + ".key";
public static final String TYPE = Tokens.makeNamespace(PropertyMap.class) + ".type";
public enum Counters {
VERTICES_PROCESSED,
OUT_EDGES_PROCESSED
}
public static Configuration createConfiguration(final Class<? extends Element> klass, final String key, final Class<? extends WritableComparable> type) {
final Configuration configuration = new EmptyConfiguration();
configuration.setClass(CLASS, klass, Element.class);
configuration.set(KEY, key);
configuration.setClass(TYPE, type, WritableComparable.class);
return configuration;
}
public static class Map extends Mapper<NullWritable, FaunusVertex, NullWritable, WritableComparable> {
private String key;
private boolean isVertex;
private WritableHandler handler;
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.key = context.getConfiguration().get(KEY);
this.handler = new WritableHandler(context.getConfiguration().getClass(TYPE, Text.class, WritableComparable.class));
this.outputs = new SafeMapperOutputs(context);
}
@Override
public void map(final NullWritable key, final FaunusVertex value, final Mapper<NullWritable, FaunusVertex, NullWritable, WritableComparable>.Context context) throws IOException, InterruptedException {
this.outputs.write(Tokens.GRAPH, NullWritable.get(), value);
if (this.isVertex) {
if (value.hasPaths()) {
WritableComparable writable = this.handler.set(ElementPicker.getProperty(value, this.key));
for (int i = 0; i < value.pathCount(); i++) {
this.outputs.write(Tokens.SIDEEFFECT, NullWritable.get(), writable);
}
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()) {
WritableComparable writable = this.handler.set(ElementPicker.getProperty(edge, this.key));
for (int i = 0; i < edge.pathCount(); i++) {
this.outputs.write(Tokens.SIDEEFFECT, NullWritable.get(), writable);
}
edgesProcessed++;
}
}
context.getCounter(Counters.OUT_EDGES_PROCESSED).increment(edgesProcessed);
}
}
@Override
public void cleanup(final Mapper<NullWritable, FaunusVertex, NullWritable, WritableComparable>.Context context) throws IOException, InterruptedException {
this.outputs.close();
}
}
}