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Java example source code file (GraphTransformer.java)

This example Java source code file (GraphTransformer.java) is included in the alvinalexander.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

Learn more about this Java project at its project page.

Java - Java tags/keywords

atomicinteger, builder, building, graphtransformer, graphwalker, huffman, igraph, iterator, labelsprovider, override, please, sequenceelement, unsupportedoperationexception, util, vocabcache

The GraphTransformer.java Java example source code

package org.deeplearning4j.models.sequencevectors.transformers.impl;

import lombok.NonNull;
import org.deeplearning4j.models.sequencevectors.graph.enums.NoEdgeHandling;
import org.deeplearning4j.models.sequencevectors.graph.enums.WalkDirection;
import org.deeplearning4j.models.sequencevectors.graph.enums.WalkMode;
import org.deeplearning4j.models.sequencevectors.graph.huffman.GraphHuffman;
import org.deeplearning4j.models.sequencevectors.graph.primitives.IGraph;
import org.deeplearning4j.models.sequencevectors.graph.walkers.GraphWalker;
import org.deeplearning4j.models.sequencevectors.graph.walkers.impl.RandomWalker;
import org.deeplearning4j.models.sequencevectors.sequence.Sequence;
import org.deeplearning4j.models.sequencevectors.sequence.SequenceElement;
import org.deeplearning4j.models.word2vec.Huffman;
import org.deeplearning4j.models.word2vec.wordstore.VocabCache;
import org.deeplearning4j.text.labels.LabelsProvider;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.util.Arrays;
import java.util.Iterator;
import java.util.List;
import java.util.concurrent.atomic.AtomicInteger;

 * This class is used to build vocabulary and sequences out of graph, via GraphWalkers
 * @author raver119@gmail.com
public class GraphTransformer<T extends SequenceElement> implements Iterable> {
    protected IGraph<T, ?> sourceGraph;
    protected GraphWalker<T> walker;
    protected LabelsProvider<T> labelsProvider;
    protected AtomicInteger counter = new AtomicInteger(0);
    protected boolean shuffle = true;
    protected VocabCache<T> vocabCache;

    protected static final Logger log = LoggerFactory.getLogger(GraphTransformer.class);

    protected GraphTransformer() {

     * This method handles required initialization for GraphTransformer
    protected void initialize() {
        log.info("Building Huffman tree for source graph...");
        int nVertices = sourceGraph.numVertices();
        //int[] degrees = new int[nVertices];
        //for( int i=0; i<nVertices; i++ )
           // degrees[i] = sourceGraph.getVertexDegree(i);
        for (int y = 0; y < nVertices; y+= 20) {
            int[] copy = Arrays.copyOfRange(degrees, y, y+20);
            System.out.println("D: " + Arrays.toString(copy));
//        GraphHuffman huffman = new GraphHuffman(nVertices);
//        huffman.buildTree(degrees);

        log.info("Transferring Huffman tree info to nodes...");
        for (int i = 0; i < nVertices; i++) {
            T element = sourceGraph.getVertex(i).getValue();

            if (vocabCache != null) vocabCache.addToken(element);

        if (vocabCache != null) {
            Huffman huffman = new Huffman(vocabCache.vocabWords());

    public Iterator<Sequence iterator() {
        return new Iterator<Sequence() {
            private GraphWalker<T> walker = GraphTransformer.this.walker;

            public void remove() {
                throw new UnsupportedOperationException("This is not supported on read-only iterator");

            public boolean hasNext() {
                return walker.hasNext();

            public Sequence<T> next() {
                Sequence<T> sequence = walker.next();

                if (labelsProvider != null) {
                    // TODO: sequence labels to be implemented for graph walks
                return sequence;

    public static class Builder<T extends SequenceElement> {
        protected IGraph<T, ?> sourceGraph;
        protected LabelsProvider<T> labelsProvider;
        protected GraphWalker<T> walker;
        protected boolean shuffle = true;
        protected VocabCache<T> vocabCache;

        public Builder(IGraph<T, ?> sourceGraph) {
            this.sourceGraph = sourceGraph;

        public Builder<T> setLabelsProvider(@NonNull LabelsProvider provider) {
            this.labelsProvider = provider;
            return this;

        public Builder<T> setGraphWalker(@NonNull GraphWalker walker) {
            this.walker = walker;
            return this;

        public Builder<T> setVocabCache(@NonNull VocabCache vocabCache) {
            this.vocabCache = vocabCache;
            return this;

        public Builder<T> shuffleOnReset(boolean reallyShuffle) {
            this.shuffle = reallyShuffle;
            return this;

        public GraphTransformer<T> build() {
            GraphTransformer<T> transformer = new GraphTransformer();
            transformer.sourceGraph = this.sourceGraph;
            transformer.labelsProvider = this.labelsProvider;
            transformer.shuffle = this.shuffle;
            transformer.vocabCache = this.vocabCache;

            if (this.walker == null)
                throw new IllegalStateException("Please provide GraphWalker instance.");
            else transformer.walker = this.walker;


            return transformer;

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