1.1 --- /dev/null	Thu Jan 01 00:00:00 1970 +0000
     1.2 +++ b/task2/solution11/src/org/apidesign/apifest08/currency/Convertor.java	Wed Oct 01 10:43:05 2008 +0200
     1.3 @@ -0,0 +1,129 @@
     1.4 +package org.apidesign.apifest08.currency;
     1.5 +
     1.6 +import org.apidesign.apifest08.currency.Computer.ComputerRequest;
     1.7 +import org.apidesign.apifest08.currency.Computer.ComputerResponse;
     1.8 +
     1.9 +/**
    1.10 + * Convertor.
    1.11 + * 
    1.12 + * In Task 1's version provides conversion between currency values
    1.13 + * with amount stored in integer or double, that are identified
    1.14 + * with string value. Exchange rates are immutable.
    1.15 + * 
    1.16 + * @author ked
    1.17 + */
    1.18 +public final class Convertor<AmountType, IdentifierType> {
    1.19 +
    1.20 +    Computer<AmountType> computer;
    1.21 +    CurrencyValue<AmountType, IdentifierType> firstCurrencyExchangeRate;
    1.22 +    CurrencyValue<AmountType, IdentifierType> secondCurrencyExchangeRate;
    1.23 +
    1.24 +    Convertor(
    1.25 +            Computer<AmountType> computer,
    1.26 +            CurrencyValue<AmountType, IdentifierType> firstCurrencyExchangeRate,
    1.27 +            CurrencyValue<AmountType, IdentifierType> secondCurrencyExchangeRate) {
    1.28 +        if (firstCurrencyExchangeRate.getIdentifier() == null ||
    1.29 +            secondCurrencyExchangeRate.getIdentifier() == null ||
    1.30 +            firstCurrencyExchangeRate.getIdentifier().equals(secondCurrencyExchangeRate.getIdentifier())) {
    1.31 +                throw new IllegalArgumentException("Inappropriate exchange rates' identifiers!");
    1.32 +        }
    1.33 +        this.computer = computer;
    1.34 +        this.firstCurrencyExchangeRate = firstCurrencyExchangeRate;
    1.35 +        this.secondCurrencyExchangeRate = secondCurrencyExchangeRate;
    1.36 +    }
    1.37 +
    1.38 +    /**
    1.39 +     * Convert an amount of the one currency to an amount of the another one currency
    1.40 +     * with respect to previously specified exchange rate.
    1.41 +     * 
    1.42 +     * @param targetCurrency an identifier of the requested currency
    1.43 +     * @param currencyValue an amount of the another one currency
    1.44 +     * @return an amount of the requested currency
    1.45 +     */
    1.46 +    public CurrencyValue<AmountType, IdentifierType> convert(
    1.47 +            IdentifierType targetCurrency,
    1.48 +            CurrencyValue<AmountType, IdentifierType> currencyValue) {
    1.49 +        if (firstCurrencyExchangeRate.getIdentifier().equals(targetCurrency) &&
    1.50 +            secondCurrencyExchangeRate.getIdentifier().equals(currencyValue.getIdentifier())) {
    1.51 +            ComputerRequest<AmountType> computerRequest = new ComputerRequest<AmountType>();
    1.52 +            computerRequest.setInput(currencyValue.getAmount());
    1.53 +            computerRequest.setInputCurrencyRatio(secondCurrencyExchangeRate.getAmount());
    1.54 +            computerRequest.setOutputCurrencyRatio(firstCurrencyExchangeRate.getAmount());
    1.55 +            ComputerResponse<AmountType> computerResponse = computer.compute(computerRequest);
    1.56 +
    1.57 +            return CurrencyValue.getCurrencyValue(
    1.58 +                    computerResponse.getResult(),
    1.59 +                    firstCurrencyExchangeRate.getIdentifier());
    1.60 +        } else if (secondCurrencyExchangeRate.getIdentifier().equals(targetCurrency) &&
    1.61 +                   firstCurrencyExchangeRate.getIdentifier().equals(currencyValue.getIdentifier())) {
    1.62 +            ComputerRequest<AmountType> computerRequest = new ComputerRequest<AmountType>();
    1.63 +            computerRequest.setInput(currencyValue.getAmount());
    1.64 +            computerRequest.setInputCurrencyRatio(firstCurrencyExchangeRate.getAmount());
    1.65 +            computerRequest.setOutputCurrencyRatio(secondCurrencyExchangeRate.getAmount());
    1.66 +            ComputerResponse<AmountType> computerResponse = computer.compute(computerRequest);
    1.67 +
    1.68 +            return CurrencyValue.getCurrencyValue(
    1.69 +                    computerResponse.getResult(),
    1.70 +                    secondCurrencyExchangeRate.getIdentifier());
    1.71 +        } else {
    1.72 +            throw new IllegalArgumentException("Inappropriate currencies to convert!");
    1.73 +        }
    1.74 +    }
    1.75 +
    1.76 +    static <AmountType, IdentifierType> Convertor<AmountType, IdentifierType> getConvertor(
    1.77 +            Computer<AmountType> computer,
    1.78 +            CurrencyValue<AmountType, IdentifierType> firstCurrencyExchangeRate,
    1.79 +            CurrencyValue<AmountType, IdentifierType> secondCurrencyExchangeRate) {
    1.80 +        return new Convertor<AmountType, IdentifierType>(
    1.81 +                computer,
    1.82 +                firstCurrencyExchangeRate,
    1.83 +                secondCurrencyExchangeRate);
    1.84 +    }
    1.85 +    
    1.86 +    static final Computer<Double> DoubleComputer = new Computer<Double>() {
    1.87 +
    1.88 +        public ComputerResponse<Double> compute(ComputerRequest<Double> request) {
    1.89 +            ComputerResponse<Double> response = new ComputerResponse<Double>();
    1.90 +            response.setResult(request.getInput() * request.getOutputCurrencyRatio() / request.getInputCurrencyRatio());
    1.91 +            return response;
    1.92 +        }
    1.93 +    };
    1.94 +
    1.95 +    /**
    1.96 +     * Creates convertor for Double|String values with specified exchange rate
    1.97 +     * between two currencies.
    1.98 +     * 
    1.99 +     * @param firstCurrencyExchangeRate first currency
   1.100 +     * @param secondCurrencyExchangeRate second currency
   1.101 +     * @return convertor
   1.102 +     */
   1.103 +
   1.104 +    public static Convertor<Double, String> getConvertorDoubleString(
   1.105 +            CurrencyValue<Double, String> firstCurrencyExchangeRate,
   1.106 +            CurrencyValue<Double, String> secondCurrencyExchangeRate) {
   1.107 +        return getConvertor(DoubleComputer, firstCurrencyExchangeRate, secondCurrencyExchangeRate);
   1.108 +    }
   1.109 +    
   1.110 +    static final Computer<Integer> IntegerComputer = new Computer<Integer>() {
   1.111 +
   1.112 +        public ComputerResponse<Integer> compute(ComputerRequest<Integer> request) {
   1.113 +            ComputerResponse<Integer> response = new ComputerResponse<Integer>();
   1.114 +            response.setResult(request.getInput() * request.getOutputCurrencyRatio() / request.getInputCurrencyRatio());
   1.115 +            return response;
   1.116 +        }
   1.117 +    };
   1.118 +
   1.119 +    /**
   1.120 +     * Creates convertor for Integer|String values with specified exchange rate
   1.121 +     * between two currencies.
   1.122 +     * 
   1.123 +     * @param firstCurrencyExchangeRate first currency
   1.124 +     * @param secondCurrencyExchangeRate second currency
   1.125 +     * @return convertor
   1.126 +     */
   1.127 +    public static Convertor<Integer, String> getConvertorIntegerString(
   1.128 +            CurrencyValue<Integer, String> firstCurrencyExchangeRate,
   1.129 +            CurrencyValue<Integer, String> secondCurrencyExchangeRate) {
   1.130 +        return getConvertor(IntegerComputer, firstCurrencyExchangeRate, secondCurrencyExchangeRate);
   1.131 +    }
   1.132 +}