// This file contains material supporting section 2.8 of the textbook:
// "Object Oriented Software Engineering" and is issued under the open-source
// license found at www.lloseng.com 

package postalcode;

/**
 * This class is a subclass of PostalCode used to handle and verify
 * US ZIP codes.
 *
 * @author François Bélanger
 * @author Dr Timothy C. Lethbridge
 * @version July 2001
 */
public class USZipCode extends PostalCode
{
  //Constructors ****************************************************
  
  /**
   * Constructs a ZIP Code type object.  Calls the superclass
   * constructor.
   *
   * @param code The postal code to be analysed.
   */
  public USZipCode(String code) throws PostalCodeException
  {
    super(code);
  }
  
 
 //Instance methods ************************************************
  
  /**
   * This method returns the country of origin of this code.
   *
   * @return A String containing the country of origin of the code.
   */
  public String getCountry()
  {
    return "American";
  }
	
  /**
   * This method validates the postal code.
   *
   * @throws PostalCodeException If the code is invalid.
   */
  protected void validate() throws PostalCodeException
  {
    String postCode = getCode();
    switch(postCode.length())
    {
      // If the code is 5 or 10 characters long
      case 5:
      case 10:
        for (int i = 0; i < postCode.length(); i++) //Check chars
        {
          if (((i == 5) && (postCode.charAt(i) != '-'))
            || ((i != 5) && (!(Character.isDigit(postCode.charAt(i))))))
          {
            // Checks both 5 and 10 characters
            // If all the characters except the 6th are not numbers
            // If the 6th character (in 10 characters) is not a dash
            throwException("Invalid character in code.");
            break;
          }
        }
        break;

      default:
        //Any other case, the code is invalid.
        throwException("Invalid code length.");
    }

    setDestination(computeDestination());
  }

  /**
   * This method will return a String indicating the location of the
   * destination address.  10 character codes have destinations in major
   * cities, while 5 character codes have destination in minor cities.
   *
   * @return A String indicating the size of the city where the destination
   *         is located.
   */
  private String computeDestination()
  {
    if (getCode().length() == 10)
      return "in a major US city.";
    else
      return "in a small US city.";
  }
}