TimeConverter.java

package time;

import java.util.HashMap;
import java.util.Map;

public class TimeConverter {

    private HashMap<String, Integer> timeMappings = new HashMap<>();

    public TimeConverter() {
        timeMappings.put("second", 1);
        timeMappings.put("minute", 60);
        timeMappings.put("hour", 3600);
        timeMappings.put("day", 86400);
        timeMappings.put("week", 604800);
        //add as many units as you want
    }

    public int unitToSeconds(String unit) {
        int result = -1;
        if (timeMappings.containsKey(unit)) {
            result = timeMappings.get(unit);
        }
        return result;
    }

    public String secondsToUnit(int seconds) {
        String result = "no match";
        for(Map.Entry<String, Integer> entry : timeMappings.entrySet()) {
            if(entry.getValue() == seconds) {
                result = entry.getKey();
            }
        }
        return result;
    }

    public static void main(String[] args) {
        TimeConverter t = new TimeConverter();
        System.out.println(t.secondsToUnit(60));
        System.out.println(t.secondsToUnit(604800));
        System.out.println(t.secondsToUnit(999));
        System.out.println(t.unitToSeconds("second"));
        System.out.println(t.unitToSeconds("hour"));
        System.out.println(t.unitToSeconds("henway"));
    }
}