1.1 --- /dev/null	Thu Jan 01 00:00:00 1970 +0000
     1.2 +++ b/task1/solution12/src/org/apidesign/apifest08/currency/Convertor.java	Sun Sep 28 14:12:38 2008 +0200
     1.3 @@ -0,0 +1,110 @@
     1.4 +package org.apidesign.apifest08.currency;
     1.5 +
     1.6 +import java.util.Currency;
     1.7 +
     1.8 +/**
     1.9 + * This is the skeleton class for your API. You need to make it public, so it is accessible to your client code
    1.10 + * (currently in Task1Test.java) file.
    1.11 + * <p>
    1.12 + * Feel free to create additional classes or rename this one, just keep all the API and its implementation in this
    1.13 + * package. Do not spread it outside to other packages.
    1.14 + */
    1.15 +public class Convertor {
    1.16 +
    1.17 +  private Currency currency1;
    1.18 +  private Currency currency2;
    1.19 +
    1.20 +  private Convertor(Currency currency1, Currency currency2) {
    1.21 +    this.currency1 = currency1;
    1.22 +    this.currency2 = currency2;
    1.23 +  }
    1.24 +
    1.25 +  /**
    1.26 +   * Creates new instance of convertor.
    1.27 +   * @param currency1
    1.28 +   *          one of the currencies we want to convert to/from
    1.29 +   * @param currency2
    1.30 +   *          the other currency
    1.31 +   * @return new instance of convertor
    1.32 +   */
    1.33 +  public static Convertor getConvertorInstance(Currency currency1, Currency currency2) {
    1.34 +    if (currency1 == null || currency2 == null)
    1.35 +      throw new ConvertorException("None of the currencies should be null!!!");
    1.36 +    return new Convertor(currency1, currency2);
    1.37 +  }
    1.38 +
    1.39 +  /**
    1.40 +   * Converts selected amout of selected currency to other currency of this convertor instance.
    1.41 +   * @param amount
    1.42 +   *          amount to convert
    1.43 +   * @param actualCurrency
    1.44 +   *          currency of this amount
    1.45 +   * @return converted amount
    1.46 +   */
    1.47 +  public double convert(double amount, Currency actualCurrency) {
    1.48 +    ExchangeRate exchangeRate = null;
    1.49 +
    1.50 +    if (actualCurrency == null) {
    1.51 +      throw new ConvertorException("Selected currency is null!!!");
    1.52 +    }
    1.53 +
    1.54 +    if (currency1.getSymbol().equals(actualCurrency.getSymbol())
    1.55 +        || currency2.getSymbol().equals(actualCurrency.getSymbol())) {
    1.56 +      exchangeRate = getExchangeRate(actualCurrency);
    1.57 +    } else {
    1.58 +      throw new ConvertorException("This convertor could not be used for selected currency("
    1.59 +          + actualCurrency.getCurrencyCode() + ") " + this + "!!!");
    1.60 +    }
    1.61 +
    1.62 +    return countResult(exchangeRate, amount);
    1.63 +  }
    1.64 +
    1.65 +  private double countResult(ExchangeRate exchangeRate, double amount) {
    1.66 +    return amount * exchangeRate.getRate() / exchangeRate.getUnit();
    1.67 +  }
    1.68 +
    1.69 +  /**
    1.70 +   * Decides the direction of conversion and returns instance of actual exchange rate.
    1.71 +   * @param actualCurrency
    1.72 +   *          actual currency we want to convert
    1.73 +   * @return actual exchange rate of this convertor for selected currency
    1.74 +   */
    1.75 +  private ExchangeRate getExchangeRate(Currency actualCurrency) {
    1.76 +    ExchangeRate exchangeRate = null;
    1.77 +
    1.78 +    if (actualCurrency.getCurrencyCode().equals(currency1.getCurrencyCode())) {
    1.79 +      exchangeRate = getExchangeRateInstance(actualCurrency, currency2);
    1.80 +    } else if (actualCurrency.getCurrencyCode().equals(currency2.getCurrencyCode())) {
    1.81 +      exchangeRate = getExchangeRateInstance(actualCurrency, currency1);
    1.82 +    }
    1.83 +
    1.84 +    return exchangeRate;
    1.85 +  }
    1.86 +
    1.87 +  /**
    1.88 +   * Returns actual exchange rate between original and destination currency.
    1.89 +   * @param originalCurrency
    1.90 +   *          original currency, from which we want to convert
    1.91 +   * @param newCurrency
    1.92 +   *          destination currency, to which we want to convert
    1.93 +   * @return exchange rate between this two currencies
    1.94 +   */
    1.95 +  private ExchangeRate getExchangeRateInstance(Currency originalCurrency, Currency newCurrency) {
    1.96 +    if ("USD".equals(originalCurrency.getCurrencyCode()) && "CZK".equals(newCurrency.getCurrencyCode())) {
    1.97 +      return new ExchangeRate(originalCurrency, newCurrency, 17d, 1d);
    1.98 +    } else if ("CZK".equals(originalCurrency.getCurrencyCode()) && "USD".equals(newCurrency.getCurrencyCode())) {
    1.99 +      return new ExchangeRate(originalCurrency, newCurrency, 1d / 17d, 1d);
   1.100 +    } else if ("SKK".equals(originalCurrency.getCurrencyCode()) && "CZK".equals(newCurrency.getCurrencyCode())) {
   1.101 +      return new ExchangeRate(originalCurrency, newCurrency, 80d, 100d);
   1.102 +    } else if ("CZK".equals(originalCurrency.getCurrencyCode()) && "SKK".equals(newCurrency.getCurrencyCode())) {
   1.103 +      return new ExchangeRate(originalCurrency, newCurrency, 100d / (80d / 100d), 100d);
   1.104 +    } else {
   1.105 +      throw new ConvertorException("Defined currencies don't have secified rates ["
   1.106 +          + originalCurrency.getCurrencyCode() + ", " + newCurrency.getCurrencyCode() + "]!!!");
   1.107 +    }
   1.108 +  }
   1.109 +
   1.110 +  public String toString() {
   1.111 +    return "Converter [" + currency1.getCurrencyCode() + ", " + currency2.getCurrencyCode() + "]";
   1.112 +  }
   1.113 +}