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/*
 * Copyright (c) 2010-2021 Haifeng Li. All rights reserved.
 *
 * Smile is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * Smile is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with Smile.  If not, see .
 */

package smile.data.measure;

import java.io.Serializable;
import java.text.NumberFormat;

/**
 * Level of measurement or scale of measure is a classification that
 * describes the nature of information within the values assigned to
 * variables. Psychologist Stanley Smith Stevens developed the best-known
 * classification with four levels, or scales, of measurement: nominal,
 * ordinal, interval, and ratio. Each scale of measurement has certain
 * properties which in turn determines the appropriateness for use of
 * certain statistical analyses.
 *
 * @author Haifeng Li
 */
public interface Measure extends Serializable {
    /** Currency. */
    RatioScale Currency = new RatioScale(NumberFormat.getCurrencyInstance());

    /** Percent. */
    RatioScale Percent = new RatioScale(NumberFormat.getPercentInstance());

    /**
     * Returns a measurement value object represented by the argument string s.
     * @param s a string.
     * @return the parsed value.
     */
    Number valueOf(String s) throws NumberFormatException;

    /**
     * Returns the string representation of an object in the measure.
     * @param o an object.
     * @return the string representation
     */
    String toString(Object o);
}