CsvTimeSeriesParser.java

package nl.wldelft.timeseriesparsers;

import nl.wldelft.util.TextUtils;
import nl.wldelft.util.io.LineReader;
import nl.wldelft.util.io.TextParser;
import nl.wldelft.util.timeseries.DefaultTimeSeriesHeader;
import nl.wldelft.util.timeseries.TimeSeriesContentHandler;

import java.io.IOException;

/**
 * TimeSeries reader for CSV files with a simple structure (quite like the CSV files FEWS can export)
 * <p>
 * A detailed description can be found in JIRA issue FEWS-1995
 *<pre>
 *Example
 *Location Names,Bewdley,Saxons Lode
 *Location Ids,EA_H-2001,EA_H-2032
 *Time,Rainfall,Rainfall
 *2003-03-01 01:00:00,-999,-999
 *2003-03-01 01:15:00,1.000,1.000
 *2003-03-01 01:30:00,2.000,2.000
 *2003-03-01 01:45:00,3.000,3.000
 *2003-03-01 02:00:00,4.000,4.000
 *2003-03-01 02:15:00,-999,5.000
 *2003-03-01 02:30:00,6.000,6.000
 *2003-03-01 02:45:00,7.000,7.000
 *2003-03-01 03:00:00,8.000,8.000
 *2003-03-01 03:15:00,9.000,9.000
 *2003-03-01 03:30:00,10.000,10.000
 *2003-03-01 03:45:00,11.000,11.000
 *2003-03-01 04:00:00,12.000,12.000
 *2003-03-01 04:15:00,13.000,13.000
 *2003-03-01 04:30:00,14.000,14.986
 *</pre>
 */
public class CsvTimeSeriesParser implements TextParser<TimeSeriesContentHandler> {
    private static final char[] QUOTE_CHARACTERS = new char[]{'\'', '\"'};
    private char decimalSeparator = '\0';
    private int columnCount = 0;
    private LineReader reader = null;
    private TimeSeriesContentHandler contentHandler = null;
    private char columnSeparatorChar = '\0';

    @Override
    public void parse(LineReader reader, String virtualFileName, TimeSeriesContentHandler contentHandler) throws IOException {
        this.contentHandler = contentHandler;
        this.contentHandler.addMissingValueRange(-999.9999f, -999f);

        this.reader = reader;
        parseHeader();

        for (String[] buffer = new String[columnCount]; this.reader.readLine(columnSeparatorChar, buffer) != -1;) {
            this.contentHandler.setTime(this.contentHandler.getDefaultTimeZone(), "yyyy-MM-dd HH:mm:ss", buffer[0]);
            for (int i = 1; i < columnCount; i++) {
                this.contentHandler.setTimeSeriesHeader(i);
                this.contentHandler.setValue(decimalSeparator, buffer[i]);
                this.contentHandler.applyCurrentFields();
            }
        }
    }

    // The first few lines contain vital information about the file:
    // - Whether the separator character is a , or a ;
    // - The names of the parameters and locations

    private void parseHeader() throws IOException {
        String locationNamesLine = reader.readLine();
        if (locationNamesLine.contains(";") && !locationNamesLine.contains(",")) {
            columnSeparatorChar = ';';
            decimalSeparator = ',';
        } else {
            columnSeparatorChar = ',';
            decimalSeparator = '.';
        }

        String[] locationIdsLine = reader.readLine(columnSeparatorChar);
        String[] parameterIdsAndUnitsLine = reader.readLine(columnSeparatorChar);

        if (locationIdsLine.length != parameterIdsAndUnitsLine.length)
            throw new IOException("Number of locations not the same as the number of parameters\n" + reader.getFileAndLineNumber());

        columnCount = locationIdsLine.length;

        DefaultTimeSeriesHeader header = new DefaultTimeSeriesHeader();
        for (int i = 1; i < columnCount; i++) {
            header.setLocationId(locationIdsLine[i]);
            String parAndUnit = parameterIdsAndUnitsLine[i];
            header.setParameterId(getName(parAndUnit));
            header.setUnit(getUnit(parAndUnit));
            contentHandler.createTimeSeriesHeaderAlias(i, header);
        }
    }

    private static String getName(String string) {
        String res = TextUtils.leftFrom(string, '[');
        if (res == null) res = string;
        if (res == null) return null;
        return TextUtils.removeCharacters(res, QUOTE_CHARACTERS);
    }

    private static String getUnit(String string) {
        String res = TextUtils.getTextBetween(string, "[", "]");
        if (res == null) return null;
        return TextUtils.removeCharacters(res, QUOTE_CHARACTERS);
    }

}