org.codelibs.elasticsearch.taste.similarity.precompute.BatchItemSimilarities Maven / Gradle / Ivy

Go to download
/**
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.codelibs.elasticsearch.taste.similarity.precompute;

import java.io.IOException;

import org.codelibs.elasticsearch.taste.recommender.ItemBasedRecommender;

public abstract class BatchItemSimilarities {

    private final ItemBasedRecommender recommender;

    private final int similarItemsPerItem;

    /**
     * @param recommender recommender to use
     * @param similarItemsPerItem number of similar items to compute per item
     */
    protected BatchItemSimilarities(final ItemBasedRecommender recommender,
            final int similarItemsPerItem) {
        this.recommender = recommender;
        this.similarItemsPerItem = similarItemsPerItem;
    }

    protected ItemBasedRecommender getRecommender() {
        return recommender;
    }

    protected int getSimilarItemsPerItem() {
        return similarItemsPerItem;
    }

    /**
     * @param degreeOfParallelism number of threads to use for the computation
     * @param maxDurationInHours  maximum duration of the computation
     * @param writer  {@link SimilarItemsWriter} used to persist the results
     * @return  the number of similarities precomputed
     * @throws IOException
     * @throws RuntimeException if the computation takes longer than maxDurationInHours
     */
    public abstract int computeItemSimilarities(int degreeOfParallelism,
            int maxDurationInHours, SimilarItemsWriter writer)
            throws IOException;
}