package com.imsl.test.example.io;

import com.imsl.io.FlatFile;
import com.imsl.stat.Summary;
import java.io.*;
import java.sql.SQLException;
import java.util.StringTokenizer;

/**
 *
 * <h4> Reads Fisher's Iris data set from a CSV file.</h4>
 *
 * The Fisher iris data set is frequently used as a sample statistical data set.
 * This example reads the data set in a CSV (comma separated value) format.
 *
 * <p>
 * The first few lines of the data set are as follows:  <code><pre>
 * Species,Sepal Length,Sepal Width,Petal Length,Petal Width
 * 1.0, 5.1, 3.5, 1.4, .2
 * 1.0, 4.9, 3.0, 1.4, .2
 * 1.0, 4.7, 3.2, 1.3, .2
 * 1.0, 4.6, 3.1, 1.5, .2
 * 1.0, 5.0, 3.6, 1.4, .2
 * 1.0, 5.4, 3.9, 1.7, .4
 * </pre></code></p>
 * <p>
 * The first line contains the column names, with a comma as the separator. The
 * rest of the lines contain <code>double</code> data, one observation per line,
 * with comma as a separator.
 * </p>
 * <p>
 * This example extends the class {@link FlatFile}. The <code>FlatFileEx1</code>
 * constructor constructs a <code>BufferedReader</code> object and calls the
 * <code>FlatFile</code> constructor. It then reads the line containing the
 * column names. The column names are parsed and used to set the column names in
 * <code>FlatFile</code>. All of the columns are also set to type <code>
 * Double</code>.
 * </p>
 * <p>
 * The class <code>FlatFileEx1</code> is used in the method <code>main</code>.
 * The data set is assumed to be in a file called "FisherIris.csv" in the same
 * location as the example class file, so that <code>getResourceAsStream</code>
 * can be used to open the file as a stream. Summary statistics are computed for
 * the "Sepal Width" column.
 * </p>
 *
 * @see <a href="FlatFileEx1.java">Code</a>
 * @see <a href="doc-files/FlatFileEx1.out">Output</a>
 *
 */
public class FlatFileEx1 extends FlatFile {

    public FlatFileEx1(InputStream is) throws IOException {
        super(new BufferedReader(new InputStreamReader(is)));
        String line = readLine();
        StringTokenizer st = new StringTokenizer(line, ",");
        for (int j = 0; st.hasMoreTokens(); j++) {
            setColumnName(j + 1, st.nextToken().trim());
            setColumnClass(j, Double.class);
        }
    }

    public static void main(String[] args) throws SQLException, IOException {
        InputStream is
                = FlatFileEx1.class.getResourceAsStream("FisherIris.csv");
        FlatFileEx1 iris = new FlatFileEx1(is);

        Summary summary = new Summary();
        while (iris.next()) {
            summary.update(iris.getDouble("Sepal Width"));
        }

        System.out.println("Sepal Width mean " + summary.getMean());
        System.out.println("Sepal Width variance " + summary.getVariance());

        iris.close();
        is.close();
    }
}