com.tinkerpop.gremlin.giraph.process.computer.util.MemoryMapReduce Maven / Gradle / Ivy

Go to download
package com.tinkerpop.gremlin.giraph.process.computer.util;

import com.tinkerpop.gremlin.giraph.Constants;
import com.tinkerpop.gremlin.process.computer.MapReduce;
import com.tinkerpop.gremlin.process.computer.Memory;
import com.tinkerpop.gremlin.structure.Vertex;
import org.apache.commons.configuration.Configuration;
import org.javatuples.Pair;

import java.util.ArrayList;
import java.util.Collections;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Set;

/**
 * @author Marko A. Rodriguez (http://markorodriguez.com)
 */
public class MemoryMapReduce implements MapReduce> {

    public Set memoryKeys = new HashSet<>();

    @Override
    public String getSideEffectKey() {
        return Constants.HIDDEN_MEMORY;
    }

    public MemoryMapReduce() {

    }

    public MemoryMapReduce(final Set memoryKeys) {
        this.memoryKeys = memoryKeys;
    }

    @Override
    public void storeState(final Configuration configuration) {
        configuration.setProperty(Constants.GREMLIN_MEMORY_KEYS, new ArrayList<>(this.memoryKeys.size()));
    }

    @Override
    public void loadState(final Configuration configuration) {
        this.memoryKeys = new HashSet((List) configuration.getList(Constants.GREMLIN_MEMORY_KEYS));
    }

    @Override
    public boolean doStage(final Stage stage) {
        return true;
    }

    @Override
    public void map(final Vertex vertex, final MapEmitter emitter) {
        final Map memoryMap = vertex.>property(Constants.MEMORY_MAP).orElse(Collections.emptyMap());
        for (final String memoryKey : this.memoryKeys) {
            if (memoryMap.containsKey(memoryKey)) {
                emitter.emit(memoryKey, memoryMap.get(memoryKey));
            }
        }
    }

    @Override
    public void combine(final String key, final Iterator