package com.thinkaurelius.faunus.mapreduce.filter;
import com.thinkaurelius.faunus.FaunusEdge;
import com.thinkaurelius.faunus.FaunusVertex;
import com.thinkaurelius.faunus.Tokens;
import com.thinkaurelius.faunus.mapreduce.util.EmptyConfiguration;
import com.tinkerpop.blueprints.Direction;
import com.tinkerpop.blueprints.Edge;
import com.tinkerpop.blueprints.Element;
import com.tinkerpop.blueprints.Vertex;
import com.tinkerpop.gremlin.groovy.jsr223.GremlinGroovyScriptEngine;
import groovy.lang.Closure;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.io.NullWritable;
import org.apache.hadoop.mapreduce.Mapper;
import javax.script.ScriptEngine;
import javax.script.ScriptException;
import java.io.IOException;
/**
* @author Marko A. Rodriguez (http://markorodriguez.com)
*/
public class FilterMap {
public static final String CLASS = Tokens.makeNamespace(FilterMap.class) + ".class";
public static final String CLOSURE = Tokens.makeNamespace(FilterMap.class) + ".closure";
private static final ScriptEngine engine = new GremlinGroovyScriptEngine();
public enum Counters {
VERTICES_FILTERED,
EDGES_FILTERED
}
public static Configuration createConfiguration(final Class<? extends Element> klass, final String closure) {
final Configuration configuration = new EmptyConfiguration();
configuration.setClass(CLASS, klass, Element.class);
configuration.set(CLOSURE, closure);
return configuration;
}
public static class Map extends Mapper<NullWritable, FaunusVertex, NullWritable, FaunusVertex> {
private boolean isVertex;
private Closure<Boolean> closure;
@Override
public void setup(final Mapper.Context context) throws IOException, InterruptedException {
this.isVertex = context.getConfiguration().getClass(CLASS, Element.class, Element.class).equals(Vertex.class);
try {
this.closure = (Closure<Boolean>) engine.eval(context.getConfiguration().get(CLOSURE));
} catch (final ScriptException e) {
throw new IOException(e.getMessage(), e);
}
}
@Override
public void map(final NullWritable key, final FaunusVertex value, final Mapper<NullWritable, FaunusVertex, NullWritable, FaunusVertex>.Context context) throws IOException, InterruptedException {
if (this.isVertex) {
if (value.hasPaths() && !this.closure.call(value)) {
value.clearPaths();
context.getCounter(Counters.VERTICES_FILTERED).increment(1l);
}
} else {
long counter = 0;
for (final Edge e : value.getEdges(Direction.BOTH)) {
final FaunusEdge edge = (FaunusEdge) e;
if (edge.hasPaths() && !this.closure.call(edge)) {
edge.clearPaths();
counter++;
}
}
context.getCounter(Counters.EDGES_FILTERED).increment(counter);
}
context.write(NullWritable.get(), value);
}
}
}