org.gradoop.io.impl.tlf.functions.TLFFileFormat.java Source code

Introduction

Here is the source code for org.gradoop.io.impl.tlf.functions.TLFFileFormat.java

Source

/*
 * This file is part of Gradoop.
 *
 * Gradoop is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * Gradoop is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with Gradoop. If not, see <http://www.gnu.org/licenses/>.
 */

package org.gradoop.io.impl.tlf.functions;

import com.google.common.collect.Lists;
import com.google.common.collect.Maps;
import org.apache.commons.lang.StringUtils;
import org.apache.flink.api.java.io.TextOutputFormat;
import org.gradoop.io.impl.tlf.tuples.TLFEdge;
import org.gradoop.io.impl.tlf.tuples.TLFGraph;
import org.gradoop.io.impl.tlf.tuples.TLFVertex;
import org.gradoop.model.api.EPGMEdge;
import org.gradoop.model.api.EPGMGraphHead;
import org.gradoop.model.api.EPGMVertex;
import org.gradoop.model.impl.id.GradoopId;
import org.gradoop.model.impl.tuples.GraphTransaction;

import java.util.Collection;
import java.util.Map;

/**
 * Converts a GraphTransaction to the following format:
 * <p>
 *   t # 0
 *   v 0 vertexLabel0
 *   v 1 vertexLabel1
 *   e 0 1 edgeLabel
 * </p>
 *
 * @param <G> EPGM graph head type
 * @param <V> EPGM vertex type
 * @param <E> EPGM edge type
 */
public class TLFFileFormat<G extends EPGMGraphHead, V extends EPGMVertex, E extends EPGMEdge>
        implements TextOutputFormat.TextFormatter<GraphTransaction<G, V, E>> {

    /**
     * Global counter for the graph id used for each single graph transaction.
     */
    private int graphId = 0;

    /**
     * Creates a TLF string representation of a given graph transaction.
     *
     * @param graphTransaction graph transaction
     * @return TLF string representation
     */
    @Override
    public String format(GraphTransaction<G, V, E> graphTransaction) {
        graphId++;

        Map<GradoopId, Integer> vertexIdMap = Maps
                .newHashMapWithExpectedSize(graphTransaction.getVertices().size());

        Collection<String> lines = Lists.newArrayListWithExpectedSize(
                graphTransaction.getVertices().size() + graphTransaction.getEdges().size() + 1);

        // GRAPH HEAD
        lines.add(TLFGraph.SYMBOL + " # " + graphId);

        // VERTICES
        int vertexId = 0;
        for (V vertex : graphTransaction.getVertices()) {
            vertexIdMap.put(vertex.getId(), vertexId);
            lines.add(TLFVertex.SYMBOL + " " + vertexId + " " + vertex.getLabel());
            vertexId++;
        }

        // EDGES
        for (E edge : graphTransaction.getEdges()) {
            Integer sourceId = vertexIdMap.get(edge.getSourceId());
            Integer targetId = vertexIdMap.get(edge.getTargetId());

            lines.add(TLFEdge.SYMBOL + " " + sourceId + " " + targetId + "" + " " + edge.getLabel());
        }
        return StringUtils.join(lines, "\n") + "\n";
    }
}