1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/task4/solution13/test/org/apidesign/apifest08/test/Task3Test.java Sat Oct 11 23:38:46 2008 +0200
1.3 @@ -0,0 +1,122 @@
1.4 +package org.apidesign.apifest08.test;
1.5 +
1.6 +import java.math.BigDecimal;
1.7 +import junit.framework.TestCase;
1.8 +import org.apidesign.apifest08.currency.Convertor;
1.9 +import org.apidesign.apifest08.currency.ConvertorCurrency;
1.10 +import org.apidesign.apifest08.currency.ExchangeRateProvider;
1.11 +import org.apidesign.apifest08.currency.IExchangeRateEngine;
1.12 +
1.13 +/** The exchange rates are not always the same. They are changing. Day by day,
1.14 + * hour by hour, minute by minute. For every bank it is important to always
1.15 + * have the actual exchange rate available in the system. That is why let's
1.16 + * create a pluggable convertor that will always have up to date value of its
1.17 + * exchange rate.
1.18 + * <p>
1.19 + * The quest for today is to allow 3rd party developer to write a convertor
1.20 + * that adjusts its exchange rate everytime it is queried. This convertor is
1.21 + * written by independent vendor, the vendor knows only your Convertor API,
1.22 + * he does not know how the whole system looks and how the convertor is supposed
1.23 + * to be used.
1.24 + */
1.25 +public class Task3Test extends TestCase {
1.26 +
1.27 + private static ConvertorCurrency currencyCZK = ConvertorCurrency.getInstance("CZK");
1.28 + private static ConvertorCurrency currencySKK = ConvertorCurrency.getInstance("SKK");
1.29 + private static ConvertorCurrency currencyUSD = ConvertorCurrency.getInstance("USD");
1.30 +
1.31 + public Task3Test(String testName) {
1.32 + super(testName);
1.33 + }
1.34 +
1.35 + @Override
1.36 + protected void setUp() throws Exception {
1.37 + }
1.38 +
1.39 + @Override
1.40 + protected void tearDown() throws Exception {
1.41 + }
1.42 +
1.43 + // Backward compatibly enhance your existing API to support following
1.44 + // usecases:
1.45 + //
1.46 +
1.47 +
1.48 + /** Without knowing anything about the surrounding system, write an
1.49 + * implementation of convertor that will return different rates everytime
1.50 + * it is queried. Convert USD to CZK and vice versa. Start with the rate of
1.51 + * 1USD = 16CZK and adjust it in favor of CZK by 0.01 CZK with every query.
1.52 + * As soon as you reach 1USD = 15CZK adjust it by 0.01 CZK in favor of USD
1.53 + * until you reach 1USD = 16CZK
1.54 + *
1.55 + * @return new instance of "online" USD and CZK convertor starting with rate 1USD = 16CZK
1.56 + */
1.57 + public static Convertor createOnlineCZKUSDConvertor() {
1.58 + // initial rate: 1USD = 16CZK
1.59 + // 2nd query 1USD = 15.99CZK
1.60 + // 3rd query 1USD = 15.98CZK
1.61 + // until 1USD = 15.00CZK
1.62 + // then 1USD = 15.01CZK
1.63 + // then 1USD = 15.02CZK
1.64 + // and so on and on up to 1USD = 16CZK
1.65 + // and then another round to 15, etc.
1.66 + IExchangeRateEngine engine = BouncingExchangeRateEngine.create(
1.67 + currencyUSD, new BigDecimal(1),
1.68 + currencyCZK,
1.69 + new BigDecimal(16),new BigDecimal(15),
1.70 + new BigDecimal("-0.01"));
1.71 + ExchangeRateProvider exRateProvider = ExchangeRateProvider.createExchangeRateProvider(engine);
1.72 + Convertor convertor = Convertor.createConvertor(exRateProvider);
1.73 + return convertor;
1.74 + }
1.75 +
1.76 + public void testFewQueriesForOnlineConvertor() {
1.77 + Convertor c = createOnlineCZKUSDConvertor();
1.78 + doFewQueriesForOnlineConvertor(c);
1.79 + }
1.80 +
1.81 + static void doFewQueriesForOnlineConvertor(Convertor c) {
1.82 + // convert $5 to CZK using c:
1.83 + assertEquals("Result is 80 CZK", new BigDecimal("80.00"), c.convertWithReversibleRates(currencyUSD, currencyCZK, new BigDecimal(5)).getConverted());
1.84 +
1.85 + // convert $8 to CZK using c:
1.86 + assertEquals("Result is 127.92 CZK", new BigDecimal("127.92"), c.convertWithReversibleRates(currencyUSD, currencyCZK, new BigDecimal(8)).getConverted());
1.87 +
1.88 + // convert $1 to CZK using c:
1.89 + assertEquals("Result is 15.98 CZK", new BigDecimal("15.98"), c.convertWithReversibleRates(currencyUSD, currencyCZK, new BigDecimal(1)).getConverted());
1.90 +
1.91 + // convert 15.97CZK to USD using c:
1.92 + assertEquals("Result is 15.98 CZK", new BigDecimal("1.00"), c.convertWithReversibleRates(currencyCZK, currencyUSD , new BigDecimal("15.97")).getConverted());
1.93 + }
1.94 +
1.95 + /** Join the convertors and show they behave sane.
1.96 + */
1.97 + public void testOnlineConvertorComposition() throws Exception {
1.98 + Convertor c = Task2Test.merge(
1.99 + createOnlineCZKUSDConvertor(),
1.100 + Task1Test.createSKKtoCZK()
1.101 + );
1.102 +
1.103 + // convert 16CZK to SKK using c:
1.104 + assertEquals("Result is 20 CZK", new BigDecimal("20.00"), c.convertWithReversibleRates(currencyCZK, currencySKK , new BigDecimal("16")).getConverted());
1.105 +
1.106 + // convert 500SKK to CZK using c:
1.107 + assertEquals("Result is 400 CZK", new BigDecimal("400.00"), c.convertWithReversibleRates(currencySKK, currencyCZK , new BigDecimal("500")).getConverted());
1.108 +
1.109 + doFewQueriesForOnlineConvertor(c);
1.110 + }
1.111 +
1.112 +// public void testBouncing() {
1.113 +// Convertor c=createOnlineCZKUSDConvertor();
1.114 +//
1.115 +// IExchangeRateEngine engine = BouncingExchangeRateEngine.create(
1.116 +// currencyUSD, new BigDecimal(1),
1.117 +// currencyCZK,
1.118 +// new BigDecimal("16.00"),new BigDecimal("15.00"),
1.119 +// new BigDecimal("-0.01"));
1.120 +//
1.121 +// for (int i=0;i<300;i++) {
1.122 +// System.out.println(engine.getExchangeRate(currencyUSD, currencyCZK).getToValue());
1.123 +// }
1.124 +// }
1.125 +}