gistfile1.java

package org.jussimononen;

import static java.lang.Integer.valueOf;

import java.util.regex.Matcher;
import java.util.regex.Pattern;

import org.joda.time.IllegalFieldValueException;
import org.joda.time.LocalTime;

public class TimeValidator {

    private static final int HOUR_GROUP_INDEX = 1;
    private static final int MINUTE_GROUP_INDEX = 2;
    private static final Pattern VALID_TIME_RE = Pattern.compile("^\\d{1,2}[:,.]\\d{2}$");
    private static final Pattern SPLIT_TIME_RE = Pattern.compile("(\\d{1,2})[:,.](\\d{2})");

    public boolean isValid(String timeString) {
        if (isValidFormat(timeString.replaceAll("\\s", ""))) {
            Time time = extractTimeComponents(timeString);
            if (isValidHour(time.hours) && isValidMinutes(time.minutes)) {
                return true;
            }
        }
        return false;
    }

    public Boolean isValid2(String timeString) {
        if (isValidFormat(timeString.replaceAll("\\s", ""))) {
            Time time = extractTimeComponents(timeString);
            try {
                LocalTime localTime = new LocalTime(valueOf(time.hours), valueOf(time.minutes));
            } catch (IllegalFieldValueException ex) {
                return false;
            }
            return true;
        }
        return false;
    }

    private Time extractTimeComponents(String timeString) {
        Matcher matcher = SPLIT_TIME_RE.matcher(timeString);
        matcher.find();
        return new Time(matcher.group(HOUR_GROUP_INDEX), matcher.group(MINUTE_GROUP_INDEX));
    }

    private boolean isValidFormat(String time) {
        return VALID_TIME_RE.matcher(time).find();
    }

    private boolean isValidMinutes(String minutes) {
        return valueOf(minutes) < 59 && valueOf(minutes) >= 0;
    }

    private boolean isValidHour(String hours) {
        return valueOf(hours) < 24 && valueOf(hours) >= 0;
    }

    private class Time {
        public final String hours;
        public final String minutes;

        public Time(String hours, String minutes) {
            this.hours = hours;
            this.minutes = minutes;

        }
    }
}