fr.inria.oak.paxquery.pact.operators.unary.SelectionOperator.java Source code

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/*******************************************************************************
 * Copyright (C) 2013, 2014, 2015 by Inria and Paris-Sud University
 * 
 * Licensed 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 fr.inria.oak.paxquery.pact.operators.unary;

import javax.xml.bind.DatatypeConverter;

import org.apache.commons.lang.SerializationUtils;
import org.apache.flink.configuration.Configuration;
import org.apache.flink.types.Record;
import org.apache.flink.util.Collector;

import fr.inria.oak.paxquery.common.datamodel.metadata.NestedMetadata;
import fr.inria.oak.paxquery.common.predicates.BasePredicate;
import fr.inria.oak.paxquery.pact.configuration.PACTOperatorsConfiguration;
import fr.inria.oak.paxquery.pact.operations.RecordPredicateEvaluation;
import fr.inria.oak.paxquery.pact.operators.BaseMapOperator;

/**
 * Selection operator in PACT.
 * 
 */
public class SelectionOperator extends BaseMapOperator {

    private BasePredicate pred;

    @Override
    public void open(Configuration parameters) throws Exception {
        super.open(parameters);

        String predEncoded = parameters.getString(PACTOperatorsConfiguration.PRED_BINARY.toString(), null);
        byte[] predBytes = DatatypeConverter.parseBase64Binary(predEncoded);
        final BasePredicate pred = (BasePredicate) SerializationUtils.deserialize(predBytes);
        this.pred = pred;
    }

    @Override
    public void map(Record record, Collector<Record> collector) {
        selection(this.inputRecordsSignature, record, this.pred, collector);
    }

    /**
     * 
     * @param record
     * @param pred
     * @param collector
     */
    public static void selection(NestedMetadata inputRecordSignature, Record record, BasePredicate pred,
            Collector<Record> collector) {
        // Evaluate predicate on record
        final boolean evaluation = RecordPredicateEvaluation.evaluate(inputRecordSignature, record, pred);

        if (evaluation)
            collector.collect(record);
    }

}