no.bekk.bekkopen.banking.KontonummerCalculator Maven / Gradle / Ivy

Go to download
package no.bekk.bekkopen.banking;

import java.util.ArrayList;
import java.util.List;

/**
 * This class calculates valid Kontonummer instances.
 */
public class KontonummerCalculator {

	private static final int LENGTH = 11;
	private static final int REGISTERNUMMER_START_DIGIT = 0;
	private static final int ACCOUNTTYPE_START_DIGIT = 4;

	private KontonummerCalculator() {
		super();
	}

	private abstract static class KontonummerDigitGenerator {
		abstract String generateKontonummer();
	}

	private static List getKontonummerListUsingGenerator(KontonummerDigitGenerator generator, int length) {
		List result = new ArrayList();
		int numAddedToList = 0;
		while (numAddedToList < length) {
			Kontonummer kontoNr;
			try {
				kontoNr = KontonummerValidator.getAndForceValidKontonummer(generator.generateKontonummer());
			} catch (IllegalArgumentException iae) {
				// this number has no valid checksum
				continue;
			}
			result.add(kontoNr);
			numAddedToList++;
		}
		return result;
	}

	/**
	 * Returns a List with random but syntactically valid Kontonummer instances
	 * for a given AccountType.
	 * 
	 * @param accountType
	 *            A String representing the AccountType to use for all
	 *            Kontonummer instances
	 * @param length
	 *            Specifies the number of Kontonummer instances to create in the
	 *            returned List
	 * @return A List with Kontonummer instances
	 */
	public static List getKontonummerListForAccountType(String accountType, int length) {
		KontonummerValidator.validateAccountTypeSyntax(accountType);
		final class AccountTypeKontonrDigitGenerator extends KontonummerDigitGenerator {
			private final String accountType;

			AccountTypeKontonrDigitGenerator(String accountType) {
				this.accountType = accountType;
			}

			@Override
			String generateKontonummer() {
				StringBuilder kontonrBuffer = new StringBuilder(LENGTH);
				for (int i = 0; i < LENGTH;) {
					if (i == ACCOUNTTYPE_START_DIGIT) {
						kontonrBuffer.append(accountType);
						i += accountType.length();
					} else {
						kontonrBuffer.append((int) (Math.random() * 10));
						i++;
					}
				}
				return kontonrBuffer.toString();
			}
		}
		return getKontonummerListUsingGenerator(new AccountTypeKontonrDigitGenerator(accountType), length);
	}

	/**
	 * Returns a List with random but syntactically valid Kontonummer instances
	 * for a given Registernummer.
	 * 
	 * @param registernummer
	 *            A String representing the Registernummer to use for all
	 *            Kontonummer instances
	 * @param length
	 *            Specifies the number of Kontonummer instances to create in the
	 *            returned List
	 * @return A List with Kontonummer instances
	 */
	public static List getKontonummerListForRegisternummer(String registernummer, int length) {
		KontonummerValidator.validateRegisternummerSyntax(registernummer);
		final class RegisternummerKontonrDigitGenerator extends KontonummerDigitGenerator {
			private final String registerNr;

			RegisternummerKontonrDigitGenerator(String registerNr) {
				this.registerNr = registerNr;
			}

			@Override
			String generateKontonummer() {
				StringBuilder kontonrBuffer = new StringBuilder(LENGTH);
				for (int i = 0; i < LENGTH;) {
					if (i == REGISTERNUMMER_START_DIGIT) {
						kontonrBuffer.append(registerNr);
						i += registerNr.length();
					} else {
						kontonrBuffer.append((int) (Math.random() * 10));
						i++;
					}
				}
				return kontonrBuffer.toString();
			}
		}
		return getKontonummerListUsingGenerator(new RegisternummerKontonrDigitGenerator(registernummer), length);
	}

	/**
	 * Returns a List with completely random but syntactically valid Kontonummer
	 * instances.
	 * 
	 * @param length
	 *            Specifies the number of Kontonummer instances to create in the
	 *            returned List
	 * 
	 * @return A List with random valid Kontonummer instances
	 */
	public static List getKontonummerList(int length) {
		final class NormalKontonrDigitGenerator extends KontonummerDigitGenerator {
			@Override
			String generateKontonummer() {
				StringBuilder kontonrBuffer = new StringBuilder(LENGTH);
				for (int i = 0; i < LENGTH; i++) {
					kontonrBuffer.append((int) (Math.random() * 10));
				}
				return kontonrBuffer.toString();
			}
		}
		return getKontonummerListUsingGenerator(new NormalKontonrDigitGenerator(), length);
	}

}