org.apache.pirk.responder.wideskies.spark.EncRowCalcPrecomputedCache.java Source code

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Here is the source code for org.apache.pirk.responder.wideskies.spark.EncRowCalcPrecomputedCache.java

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/*
 * 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.apache.pirk.responder.wideskies.spark;

import java.math.BigInteger;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;

import org.apache.pirk.query.wideskies.Query;
import org.apache.pirk.responder.wideskies.common.ComputeEncryptedRow;
import org.apache.spark.api.java.function.PairFlatMapFunction;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import scala.Tuple2;

/**
 * Functionality for computing the encrypted rows using a pre-computed, passed in modular exponentiation lookup table
 */
public class EncRowCalcPrecomputedCache implements
        PairFlatMapFunction<Tuple2<Integer, Tuple2<Iterable<Tuple2<Integer, BigInteger>>, Iterable<List<BigInteger>>>>, Long, BigInteger> {
    private static final long serialVersionUID = 1L;

    private static final Logger logger = LoggerFactory.getLogger(EncRowCalcPrecomputedCache.class);

    private Accumulators accum = null;

    Query query = null;

    private boolean limitHitsPerSelector = false;
    private int maxHitsPerSelector = 0;

    private HashMap<Integer, BigInteger> expTable = null;

    public EncRowCalcPrecomputedCache(Accumulators accumIn, BroadcastVars bvIn) {
        accum = accumIn;

        query = bvIn.getQuery();

        limitHitsPerSelector = bvIn.getLimitHitsPerSelector();
        maxHitsPerSelector = bvIn.getMaxHitsPerSelector();

        expTable = new HashMap<>();

        logger.info("Initialized EncRowCalcPrecomputedCache - limitHitsPerSelector = " + limitHitsPerSelector
                + " maxHitsPerSelector = " + maxHitsPerSelector);
    }

    @Override
    public Iterable<Tuple2<Long, BigInteger>> call(
            Tuple2<Integer, Tuple2<Iterable<Tuple2<Integer, BigInteger>>, Iterable<List<BigInteger>>>> hashDocTuple)
            throws Exception {
        List<Tuple2<Long, BigInteger>> returnPairs = new ArrayList<>();

        int rowIndex = hashDocTuple._1;
        accum.incNumHashes(1);

        // expTable: <<power>,<element^power mod N^2>>
        expTable.clear();
        Iterable<Tuple2<Integer, BigInteger>> expTableIterable = hashDocTuple._2._1;
        for (Tuple2<Integer, BigInteger> entry : expTableIterable) {
            expTable.put(entry._1, entry._2);
        }

        Iterable<List<BigInteger>> dataPartitions = hashDocTuple._2._2;

        // logger.debug("Encrypting row = " + rowIndex);
        // long startTime = System.currentTimeMillis();

        // Compute the encrypted row elements for a query from extracted data partitions
        List<Tuple2<Long, BigInteger>> encRowValues = ComputeEncryptedRow.computeEncRowCacheInput(dataPartitions,
                expTable, rowIndex, limitHitsPerSelector, maxHitsPerSelector);

        // long endTime = System.currentTimeMillis();
        // logger.info("Completed encrypting row = " + rowIndex + " duration = " + (endTime-startTime));

        returnPairs.addAll(encRowValues);

        return returnPairs;
    }
}