Java example source code file (FilteredSequenceIterator.java)

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Java - Java tags/keywords

filteredsequenceiterator, nonnull, override, sequence, sequenceelement, sequenceiterator, vocabcache

The FilteredSequenceIterator.java Java example source code

package org.deeplearning4j.models.sequencevectors.iterators;

import lombok.NonNull;
import org.deeplearning4j.models.sequencevectors.interfaces.SequenceIterator;
import org.deeplearning4j.models.sequencevectors.sequence.Sequence;
import org.deeplearning4j.models.sequencevectors.sequence.SequenceElement;
import org.deeplearning4j.models.word2vec.wordstore.VocabCache;

/**
 * This implementation of SequenceIterator passes each sequence through specified vocabulary, filtering out SequenceElements that are not available in Vocabulary.
 * Please note: nextSequence() method can return empty sequence, if none of elements were found in attached vocabulary.
 *
 * @author raver119@gmail.com
 */
public class FilteredSequenceIterator<T extends SequenceElement> implements SequenceIterator{

    private final SequenceIterator<T> underlyingIterator;
    private final VocabCache<T> vocabCache;

    /**
     * Creates Filtered SequenceIterator on top of another SequenceIterator and appropriate VocabCache instance
     *
     * @param iterator
     * @param vocabCache
     */
    public FilteredSequenceIterator(@NonNull SequenceIterator<T> iterator, @NonNull VocabCache vocabCache) {
        this.vocabCache = vocabCache;
        this.underlyingIterator = iterator;
    }

    /**
     * Checks, if there's any more sequences left in underlying iterator
     * @return
     */
    @Override
    public boolean hasMoreSequences() {
        return underlyingIterator.hasMoreSequences();
    }

    /**
     * Returns filtered sequence, that contains sequence elements from vocabulary only.
     * Please note: it can return empty sequence, if no elements were found in vocabulary
     * @return
     */
    @Override
    public Sequence<T> nextSequence() {
        Sequence<T> originalSequence = underlyingIterator.nextSequence();
        Sequence<T> newSequence = new Sequence<>();

        if (originalSequence != null) for (T element: originalSequence.getElements()) {
            if (element != null && vocabCache.hasToken(element.getLabel())) {
                newSequence.addElement(vocabCache.wordFor(element.getLabel()));
            }
        }

        newSequence.setSequenceId(originalSequence.getSequenceId());

        return newSequence;
    }

    /**
     * Resets iterator down to first sequence
     */
    @Override
    public void reset() {
        underlyingIterator.reset();
    }
}