Example usage for org.apache.mahout.cf.taste.recommender MostSimilarItemsCandidateItemsStrategy getCandidateItems

Introduction

In this page you can find the example usage for org.apache.mahout.cf.taste.recommender MostSimilarItemsCandidateItemsStrategy getCandidateItems.

Prototype

FastIDSet getCandidateItems(long[] itemIDs, DataModel dataModel) throws TasteException;

Source Link

Usage

From source file:com.buddycloud.channeldirectory.search.handler.common.mahout.ChannelRecommender.java

License:Apache License

/**
 * Recommends a list of jids of channels that are
 * similar to a given channel./*from  w  w  w.j ava2s .com*/
 * 
 * @param channelJid The channel jid
 * @param howMany The number of recommendations
 * @return A list of similar channels' jids 
 * @throws TasteException
 * @throws SQLException 
 */
public RecommendationResponse getSimilarChannels(String channelJid, int howMany)
        throws TasteException, SQLException {

    Long itemId = recommenderDataModel.toChannelId(channelJid);

    if (itemId == null) {
        return new RecommendationResponse(new LinkedList<ChannelData>(), 0);
    }

    TopItems.Estimator<Long> estimator = new MostSimilarEstimator(itemId, itemSimilarity, null);
    MostSimilarItemsCandidateItemsStrategy candidateStrategy = new PreferredItemsNeighborhoodCandidateItemsStrategy();

    FastIDSet possibleItemIDs = candidateStrategy.getCandidateItems(new long[] { itemId },
            recommenderDataModel.getDataModel());
    List<RecommendedItem> recommended = TopItems.getTopItems(howMany, possibleItemIDs.iterator(), null,
            estimator);

    List<ChannelData> recommendedChannels = new LinkedList<ChannelData>();

    for (RecommendedItem recommendedItem : recommended) {
        recommendedChannels.add(recommenderDataModel.toChannelData(recommendedItem.getItemID()));
    }

    return new RecommendationResponse(recommendedChannels, possibleItemIDs.size());
}

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