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//
// Copyright (C) 2006-2016 Talend Inc. - www.talend.com
//
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// %InstallDIR%\features\org.talend.rcp.branding.%PRODUCTNAME%\%PRODUCTNAME%license.txt
//
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// along with this program; if not, write to Talend SA
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package org.talend.dataquality.statistics.cardinality;

import java.util.Collection;
import java.util.HashSet;
import java.util.Set;

/**
 * Compute cardinalities in memory, use {@link CardinalityHLLAnalyzer} instead if large data set are computed.
 *
 * @author zhao
 */
public class CardinalityStatistics extends AbstractCardinalityStatistics<CardinalityStatistics> {

    private final Set<String> distinctData = new HashSet<>();

    public void add(String colStr) {
        distinctData.add(colStr);
    }

    public Set<String> getDistinctData() {
        return distinctData;
    }

    private void addAll(Collection<String> col) {
        this.distinctData.addAll(col);
    }

    public long getDistinctCount() {
        return distinctData.size();
    }

    /**
     * <b>This method merges two instances of CardinalityStatistics. </b>
     *
     * @param other An other instance of CardinalityStatistics
     */
    public void merge(CardinalityStatistics other) {
        super.count += other.count;
        distinctData.addAll(other.distinctData);
    }

}