1.1 --- a/task1/solution11/src/org/apidesign/apifest08/currency/Convertor.java Tue Sep 30 11:59:32 2008 +0200
1.2 +++ b/task1/solution11/src/org/apidesign/apifest08/currency/Convertor.java Tue Sep 30 12:01:18 2008 +0200
1.3 @@ -22,6 +22,11 @@
1.4 Computer<AmountType> computer,
1.5 CurrencyValue<AmountType, IdentifierType> firstCurrencyExchangeRate,
1.6 CurrencyValue<AmountType, IdentifierType> secondCurrencyExchangeRate) {
1.7 + if (firstCurrencyExchangeRate.getIdentifier() == null ||
1.8 + secondCurrencyExchangeRate.getIdentifier() == null ||
1.9 + firstCurrencyExchangeRate.getIdentifier().equals(secondCurrencyExchangeRate.getIdentifier())) {
1.10 + throw new IllegalArgumentException("Inappropriate exchange rates' identifiers!");
1.11 + }
1.12 this.computer = computer;
1.13 this.firstCurrencyExchangeRate = firstCurrencyExchangeRate;
1.14 this.secondCurrencyExchangeRate = secondCurrencyExchangeRate;
1.15 @@ -31,11 +36,26 @@
1.16 * Convert an amount of the one currency to an amount of the another one currency
1.17 * with respect to previously specified exchange rate.
1.18 *
1.19 - * @param currencyValue an amount of the one currency
1.20 - * @return an amount of the another one currency
1.21 + * @param targetCurrency an identifier of the requested currency
1.22 + * @param currencyValue an amount of the another one currency
1.23 + * @return an amount of the requested currency
1.24 */
1.25 - public CurrencyValue<AmountType, IdentifierType> convert(CurrencyValue<AmountType, IdentifierType> currencyValue) {
1.26 - if (firstCurrencyExchangeRate.getIdentifier().equals(currencyValue.getIdentifier())) {
1.27 + public CurrencyValue<AmountType, IdentifierType> convert(
1.28 + IdentifierType targetCurrency,
1.29 + CurrencyValue<AmountType, IdentifierType> currencyValue) {
1.30 + if (firstCurrencyExchangeRate.getIdentifier().equals(targetCurrency) &&
1.31 + secondCurrencyExchangeRate.getIdentifier().equals(currencyValue.getIdentifier())) {
1.32 + ComputerRequest<AmountType> computerRequest = new ComputerRequest<AmountType>();
1.33 + computerRequest.setInput(currencyValue.getAmount());
1.34 + computerRequest.setInputCurrencyRatio(secondCurrencyExchangeRate.getAmount());
1.35 + computerRequest.setOutputCurrencyRatio(firstCurrencyExchangeRate.getAmount());
1.36 + ComputerResponse<AmountType> computerResponse = computer.compute(computerRequest);
1.37 +
1.38 + return CurrencyValue.getCurrencyValue(
1.39 + computerResponse.getResult(),
1.40 + firstCurrencyExchangeRate.getIdentifier());
1.41 + } else if (secondCurrencyExchangeRate.getIdentifier().equals(targetCurrency) &&
1.42 + firstCurrencyExchangeRate.getIdentifier().equals(currencyValue.getIdentifier())) {
1.43 ComputerRequest<AmountType> computerRequest = new ComputerRequest<AmountType>();
1.44 computerRequest.setInput(currencyValue.getAmount());
1.45 computerRequest.setInputCurrencyRatio(firstCurrencyExchangeRate.getAmount());
1.46 @@ -45,18 +65,8 @@
1.47 return CurrencyValue.getCurrencyValue(
1.48 computerResponse.getResult(),
1.49 secondCurrencyExchangeRate.getIdentifier());
1.50 - } else if (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 {
1.61 - throw new IllegalArgumentException("Inappropriate currency to convert!");
1.62 + throw new IllegalArgumentException("Inappropriate currencies to convert!");
1.63 }
1.64 }
1.65
2.1 --- a/task1/solution11/test/org/apidesign/apifest08/test/Task1Test.java Tue Sep 30 11:59:32 2008 +0200
2.2 +++ b/task1/solution11/test/org/apidesign/apifest08/test/Task1Test.java Tue Sep 30 12:01:18 2008 +0200
2.3 @@ -23,8 +23,19 @@
2.4 protected void tearDown() throws Exception {
2.5 }
2.6
2.7 + //
2.8 + // Imagine that there are three parts of the whole system:
2.9 + // 1. there is someone who knows the current exchange rate
2.10 + // 2. there is someone who wants to do the conversion
2.11 + // 3. there is the API between 1. and 2. which allows them to communicate
2.12 + // Please design such API
2.13 + //
2.14 +
2.15 /** Create convertor that understands two currencies, CZK and
2.16 - * USD. Make 1 USD == 17 CZK.
2.17 + * USD. Make 1 USD == 17 CZK. This is a method provided for #1 group -
2.18 + * e.g. those that know the exchange rate. They somehow need to create
2.19 + * the objects from the API and tell them the exchange rate. The API itself
2.20 + * knows nothing about any rates, before the createCZKtoUSD method is called.
2.21 *
2.22 * Creation of the convertor shall not require subclassing of any class
2.23 * or interface on the client side.
2.24 @@ -39,7 +50,11 @@
2.25 }
2.26
2.27 /** Create convertor that understands two currencies, CZK and
2.28 - * SKK. Make 100 SKK == 80 CZK.
2.29 + * SKK. Make 100 SKK == 80 CZK. Again this is method for the #1 group -
2.30 + * it knows the exchange rate, and needs to use the API to create objects
2.31 + * with the exchange rate. Anyone shall be ready to call this method without
2.32 + * any other method being called previously. The API itself shall know
2.33 + * nothing about any rates, before this method is called.
2.34 *
2.35 * Creation of the convertor shall not require subclassing of any class
2.36 * or interface on the client side.
2.37 @@ -52,6 +67,13 @@
2.38 CurrencyValue.getCurrencyValue(80, "CZK")
2.39 );
2.40 }
2.41 +
2.42 + //
2.43 + // now the methods for group #2 follow:
2.44 + // this group knows nothing about exchange rates, but knows how to use
2.45 + // the API to do conversions. It somehow (by calling one of the factory
2.46 + // methods) gets objects from the API and uses them to do the conversions.
2.47 + //
2.48
2.49 /** Use the convertor from <code>createCZKtoUSD</code> method and do few conversions
2.50 * with it.
2.51 @@ -63,17 +85,17 @@
2.52
2.53 // convert $5 to CZK using c:
2.54 // assertEquals("Result is 85 CZK");
2.55 - result = c.convert(CurrencyValue.getCurrencyValue(5, "USD"));
2.56 + result = c.convert("CZK", CurrencyValue.getCurrencyValue(5, "USD"));
2.57 assertEquals(CurrencyValue.getCurrencyValue(85, "CZK"), result);
2.58
2.59 // convert $8 to CZK
2.60 // assertEquals("Result is 136 CZK");
2.61 - result = c.convert(CurrencyValue.getCurrencyValue(8, "USD"));
2.62 + result = c.convert("CZK", CurrencyValue.getCurrencyValue(8, "USD"));
2.63 assertEquals(CurrencyValue.getCurrencyValue(136, "CZK"), result);
2.64
2.65 // convert 1003CZK to USD
2.66 // assertEquals("Result is 59 USD");
2.67 - result = c.convert(CurrencyValue.getCurrencyValue(1003, "CZK"));
2.68 + result = c.convert("USD", CurrencyValue.getCurrencyValue(1003, "CZK"));
2.69 assertEquals(CurrencyValue.getCurrencyValue(59, "USD"), result);
2.70 }
2.71
2.72 @@ -87,13 +109,53 @@
2.73
2.74 // convert 16CZK using c:
2.75 // assertEquals("Result is 20 SKK");
2.76 - result = c.convert(CurrencyValue.getCurrencyValue(16, "CZK"));
2.77 + result = c.convert("SKK", CurrencyValue.getCurrencyValue(16, "CZK"));
2.78 assertEquals(CurrencyValue.getCurrencyValue(20, "SKK"), result);
2.79
2.80 // convert 500SKK to CZK
2.81 // assertEquals("Result is 400 CZK");
2.82 - result = c.convert(CurrencyValue.getCurrencyValue(500, "SKK"));
2.83 + result = c.convert("CZK", CurrencyValue.getCurrencyValue(500, "SKK"));
2.84 assertEquals(CurrencyValue.getCurrencyValue(400, "CZK"), result);
2.85 }
2.86 +
2.87 + /** Verify that the CZK to USD convertor knows nothing about SKK.
2.88 + */
2.89 + public void testCannotConvertToSKKwithCZKUSDConvertor() throws Exception {
2.90 + Convertor<Integer, String> c = createCZKtoUSD();
2.91 + try {
2.92 + // convert $5 to SKK, the API shall say this is not possible
2.93 + c.convert("SKK", CurrencyValue.getCurrencyValue(16, "CZK"));
2.94 + assertTrue("Should not convert", false);
2.95 + } catch (Exception e) {
2.96 + assertTrue(true);
2.97 + }
2.98 + try {
2.99 + // convert 500 SKK to CZK, the API shall say this is not possible
2.100 + c.convert("CZK", CurrencyValue.getCurrencyValue(500, "SKK"));
2.101 + assertTrue("Should not convert", false);
2.102 + } catch (Exception e) {
2.103 + assertTrue(true);
2.104 + }
2.105 +
2.106 + }
2.107 +
2.108 + /** Verify that the CZK to SKK convertor knows nothing about USD.
2.109 + */
2.110 + public void testCannotConvertToUSDwithSKKCZKConvertor() throws Exception {
2.111 + Convertor<Integer, String> c = createSKKtoCZK();
2.112 + try {
2.113 + // convert $5 to SKK, the API shall say this is not possible
2.114 + c.convert("SKK", CurrencyValue.getCurrencyValue(5, "USD"));
2.115 + assertTrue("Should not convert", false);
2.116 + } catch (Exception e) {
2.117 + assertTrue(true);
2.118 + }
2.119 + try {
2.120 + // convert 500 CZK to USD, the API shall say this is not possible
2.121 + c.convert("USD", CurrencyValue.getCurrencyValue(500, "CZK"));
2.122 + assertTrue("Should not convert", false);
2.123 + } catch (Exception e) {
2.124 + assertTrue(true);
2.125 + }
2.126 + }
2.127 }
2.128 -