package de.intevation.flys.importer;

import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.InputStreamReader;
import java.io.IOException;
import java.math.BigDecimal;
import java.text.NumberFormat;
import java.text.ParseException;

import org.apache.log4j.Logger;

import de.intevation.flys.importer.ImportDischargeTable;
import de.intevation.flys.importer.ImportDischargeTableValue;


public class AtFileParser {

    public static final String ENCODING = "ISO-8859-1";

    private static Logger logger = Logger.getLogger(AtFileParser.class);

    private static NumberFormat nf = NumberFormat.getInstance();


    public AtFileParser() {
    }


    public ImportDischargeTable parse(ImportGauge gauge) throws IOException {

        File file = gauge.getAtFile();

        logger.info("parsing AT file: " + file);

        BufferedReader br = null;

        String line       = null;

        boolean beginning = true;

        ImportDischargeTable dischargeTable = new ImportDischargeTable();

        try {
            br = new BufferedReader(
                 new InputStreamReader(
                 new FileInputStream(file), ENCODING));

            while ((line = br.readLine()) != null) {
                String tmp = line.trim();

                if (tmp.length() == 0) {
                    continue;
                }

                if (tmp.startsWith("#! name=")) {
                    // XXX Skip the name,  because we don't know where to save
                    // it at the moment

                    //String name = tmp.substring(8);
                    continue;
                }

                if (tmp.startsWith("#") || tmp.startsWith("*")) {
                    continue;
                }

                String[] splits = tmp.replace(',', '.').split("\\s+");

                if ((splits.length < 2) || (splits.length > 11)) {
                    logger.warn("Found an invalid row in the AT file.");
                    continue;
                }

                String strW = splits[0].trim();
                double W    = nf.parse(strW).doubleValue();

                /* shift is used to differenciate between lines with
                 * exactly 10 Qs and lines with less than 10 Qs. The shift
                 * is only modified when it is the first line.
                 */
                int shift = 0;

                if (splits.length != 11 && beginning) {
                    shift = 11 - splits.length;
                }


                for (int i = 1; i < splits.length; i++) {
                    double iW = W + shift + i;
                    double iQ = nf.parse(splits[i].trim()).doubleValue();

                    dischargeTable.addDischargeTableValue(
                        new ImportDischargeTableValue(
                            new BigDecimal(iQ/100.0),
                            new BigDecimal(iW/100.0)));
                }

                beginning = false;
            }
        }
        catch (ParseException pe) {
            logger.warn(pe.getMessage());
        }
        finally {
            if (br != null) {
                br.close();
            }
        }

        logger.info("Finished parsing AT file: " + file);

        return dischargeTable;
    }
}
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