com.fredericboisguerin.excel.converter.DateConverter Maven / Gradle / Ivy

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A library to read/write excel files with simple descriptions of the model

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package com.fredericboisguerin.excel.converter;

import com.fredericboisguerin.excel.StringUtils;
import org.apache.poi.ss.usermodel.DateUtil;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

/**
 * Created by fboisguerin on 22/07/2015.
 */
class DateConverter extends AbstractConverter {

    private static final DateConverter INSTANCE = new DateConverter();

    private static final SimpleDateFormat SIMPLE_DATE_FORMAT = new SimpleDateFormat("dd/MM/yyyy");

    private static final String YEAR_PATTERN = "([1-2][0-9]{3})";
    private static final String DATE_PATTERN = ".*([0-9]{2}/[0-9]{2}/[0-9]{4}).*";

    public static DateConverter getInstance() {
        return INSTANCE;
    }

    private DateConverter() {
        super(Date.class);
    }

    @Override
    protected Date innerConvert(String s) {
        if (StringUtils.isEmpty(s)) {
            return null;
        } else if (s.matches(DATE_PATTERN)) {
            return convertStringToDate(firstOccurenceOf(s, DATE_PATTERN));
        } else if (s.matches(YEAR_PATTERN)) {
            return convertStringToDate("01/01/" + firstOccurenceOf(s, YEAR_PATTERN));
        } else {
            return DateUtil.getJavaDate(Double.parseDouble(s));
        }
    }

    private static Date convertStringToDate(String dateInString) {
        try {
            return SIMPLE_DATE_FORMAT.parse(dateInString);
        } catch (ParseException e) {
            return null;
        }
    }

    public static String firstOccurenceOf(String s, String pattern) {
        Pattern p = Pattern.compile(pattern);
        Matcher m = p.matcher(s);
        if (m.matches()) {
            return m.group(1);
        } else {
            throw new IllegalArgumentException("String does not match pattern");
        }
    }
}