Methods for calculating the distance between Polish postal codes

Let's consider we are a company who sells our products for other companies. In the programme the actors are an Agency (agencies of our company, we have a few in the country, all are listed in AGENCIES in TestMain) and Client.

• Every Agency has an Address
• Every Address contents postalCode
• Every Client has a postal code

Now, in class Distance, the first method takes a postal code of the agency and the postal code of the client, calculates the longitude and latitude for these postal codes (by using DICTIONARY_POSTAL_CODES created in TestMain) and computes the distance. The second method calculates the distance from the client to the furthest agency.

It works, but is it written in a professional way?

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

public class Address {

    private String postalCode;
    private String pattern = "[0-9][0-9]-[0-9][0-9][0-9]"; //postal codes for Poland
    Pattern p = Pattern.compile(pattern);

    private void setPostalCode(String pc) {
        Matcher m = p.matcher(pc);
        if (m.find()) {
            postalCode = m.group();
        } else {
            postalCode = "-----";
        }
    }



    public Address(String pc) {
        setPostalCode(pc);
    }

    public String getPostalCode() {
        return postalCode;
    }

}

public class Agency {

    private Address address;

    public Agency(String postalCode) {
        address = new Address(postalCode);

    }


    public Address getAddress(){
        return address;
    }
}

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

public class TestMain {

    // ****************************************************************************************
    // The dictionary of postal codes and corresponding longitude/latitude
    public static Map<String, PairLongLat> createDictionaryPostalCodes() {
        Map<String, PairLongLat> dictionary = new HashMap<>();
        dictionary.put("00-000", new PairLongLat(21.04383, 52.2315136));
        dictionary.put("00-001", new PairLongLat(21.010353, 52.235382));
        dictionary.put("00-002", new PairLongLat(21.0131092, 52.2363414));
        dictionary.put("02-092", new PairLongLat(20.9790658, 52.183422));
        dictionary.put("53-605", new PairLongLat(17.0199851, 51.1088447));
        dictionary.put("61-696", new PairLongLat(16.9488458, 52.4316596));
        return dictionary;
    }

    public final static Map<String, PairLongLat> DICTIONARY_POSTAL_CODES = createDictionaryPostalCodes();

    // ****************************************************************************************
    // List of our agencies
    public static List<Agency> createAgenciesList() {
        List<Agency> agencies = new ArrayList<>();
        agencies.add(new Agency("02-092"));
        agencies.add(new Agency("53-605"));
        agencies.add(new Agency("61-696"));
        return agencies;
    }

    public final static List<Agency> AGENCIES = createAgenciesList();

    public static void main(String[] args) {

    }
}

public class Distance {

    /**
     * 
     * @param pc1
     *            - postal code first
     * @param pc2
     *            - postal code second
     * @return the euclidean distance between 2 postal codes
     */
    public double getDistance(String pc1, String pc2) {

        PairLongLat coordinates1, coordinates2;
        double long1, long2, lat1, lat2;

        coordinates1 = TestMain.DICTIONARY_POSTAL_CODES.get(pc1);
        coordinates2 = TestMain.DICTIONARY_POSTAL_CODES.get(pc2);

        long1 = coordinates1.getLongitude();
        long2 = coordinates2.getLongitude();
        lat1 = coordinates1.getLatitude();
        lat2 = coordinates2.getLatitude();

        return Math.sqrt((long1 - long2) * (long1 - long2) + (lat1 - lat2) * (lat1 - lat2));
    }

/**
     * 
     * @param pcRegCli
     *            - postal code of client
     * @return the maximum distance between (all distances between agency and
     *         client's postal code) and (client's postal code).
     */
public double getDistanceMax(String pcRegCli) {

    double distanceMax = 0;
    double tmp = 0;

    for (Agency a : TestMain.AGENCIES) {

        String pcAgency = a.getAddress().getPostalCode(); // Postal Code of
                                                            // EFL's agency
        tmp = getDistance(pcRegCli, pcAgency);

        if (tmp > distanceMax)
            distanceMax = tmp;
    }

    return distanceMax;
}
}

/**
/* this class PairLongLat is used only in creating DICTIONARY_POSTAL_CODES
/* pairs are the values of HashMap
*/

public class PairLongLat {

    private double longitude, latitude;

    public PairLongLat(double lon, double lat) {
        longitude = lon;
        latitude = lat;
    }

    public double getLongitude() {
        return longitude;
    }


    public double getLatitude() {
        return latitude;
    }


}

import static org.junit.Assert.assertEquals;

import org.junit.Test;

public class TestUnit {

    @Test
    public void testGetDistance() {

        Distance da = new Distance();

        assertEquals(0.033699763316084305, da.getDistance("00-000", "00-001"), 0);
        assertEquals(da.getDistance("00-000", "00-001"), da.getDistance("00-001", "00-000"), 0);
        assertEquals(4.09987243942609, da.getDistance("00-000", "61-696"), 0);

    }

@Test
    public void testGetDistanceMax() {

    DistanceAfs da = new DistanceAfs();

    assertEquals(4.177524774107656, da.getDistanceMax("00-000"), 0);
    assertEquals(4.146338416680638, da.getDistanceMax("00-001"), 0);
    assertEquals(4.149251605592471, da.getDistanceMax("00-002"), 0);

}
}