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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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package org.talend.dataquality.statistics.frequency;

import java.util.Map;

import org.talend.dataquality.statistics.frequency.impl.AbstractFrequencyEvaluator;
import org.talend.dataquality.statistics.frequency.impl.CMSFrequencyEvaluator;
import org.talend.dataquality.statistics.frequency.impl.EFrequencyAlgorithm;
import org.talend.dataquality.statistics.frequency.impl.NaiveFrequencyEvaluator;
import org.talend.dataquality.statistics.frequency.impl.SSFrequencyEvaluator;

/**
 * Frequency statistics bean which delegate the computation to evaluator.
 * 
 * @author mzhao
 *
 */
public abstract class AbstractFrequencyStatistics {

    private AbstractFrequencyEvaluator evaluator = new NaiveFrequencyEvaluator();

    /**
     * Set the algorithm used to compute the frequency table.
     * 
     * @param algorithm
     */
    public void setAlgorithm(EFrequencyAlgorithm algorithm) {
        switch (algorithm) {
        case NAIVE:
            evaluator = new NaiveFrequencyEvaluator();
            break;
        case SPACE_SAVER:
            evaluator = new SSFrequencyEvaluator();
            break;
        case COUNT_MIN_SKETCH:
            evaluator = new CMSFrequencyEvaluator();
            break;
        }
    }

    /**
     * Get top k frequency table.
     * 
     * @param topk
     * @return
     */
    public Map<String, Long> getTopK(int topk) {
        return evaluator.getTopK(topk);
    }

    /**
     * Get frequencies of given item
     * 
     * @param item
     * @return frequencies.
     */
    public long getFrequency(String item) {
        return evaluator.getFrequency(item);
    }

    /**
     * Parameters set as:<br>
     * {@link CMSFrequencyEvaluator#EPS }<br>
     * {@link CMSFrequencyEvaluator#SEED}<br>
     * {@link CMSFrequencyEvaluator#CONFIDENCE}<br>
     * {@link SSFrequencyEvaluator#CAPACITY}
     * 
     * @param params
     */
    public void setParameter(Map<String, String> params) {
        evaluator.setParameters(params);
    }

    public void add(String value) {
        evaluator.add(value);
    }
}