1.1 --- a/task2/solution12/src/org/apidesign/apifest08/currency/Convertor.java Wed Oct 01 11:23:11 2008 +0200
1.2 +++ b/task2/solution12/src/org/apidesign/apifest08/currency/Convertor.java Tue Oct 07 00:17:07 2008 +0200
1.3 @@ -1,7 +1,9 @@
1.4 package org.apidesign.apifest08.currency;
1.5
1.6 +import java.util.ArrayList;
1.7 import java.util.Currency;
1.8 import java.util.Hashtable;
1.9 +import java.util.List;
1.10
1.11 import org.apidesign.apifest08.currency.exceptions.ConvertorException;
1.12 import org.apidesign.apifest08.currency.exceptions.InvalidCurrencyException;
1.13 @@ -18,20 +20,19 @@
1.14
1.15 private static Hashtable<String, ExchangeRate> exchangeRates;
1.16
1.17 - private ExchangeRate exchangeRate12;
1.18 - private ExchangeRate exchangeRate21;
1.19 + private Hashtable<String, ExchangeRate> convertorInstanceExchangeRates;
1.20
1.21 - private Convertor(Currency currency1, Currency currency2) throws UnknownConvertorException {
1.22 - String key12 = currency1.getCurrencyCode() + currency2.getCurrencyCode();
1.23 - String key21 = currency2.getCurrencyCode() + currency1.getCurrencyCode();
1.24 -
1.25 - if (!(exchangeRates.containsKey(key12) && exchangeRates.containsKey(key21))) {
1.26 - throw new UnknownConvertorException("Selected convertor (" + currency1.getCurrencyCode() + "->"
1.27 - + currency2.getCurrencyCode() + ") has not defined any rates!!!");
1.28 - }
1.29 -
1.30 - this.exchangeRate12 = exchangeRates.get(key12);
1.31 - this.exchangeRate21 = exchangeRates.get(key21);
1.32 + private Convertor(List<Currency> currencies) throws UnknownConvertorException {
1.33 + convertorInstanceExchangeRates = new Hashtable<String, ExchangeRate>();
1.34 + for (Currency currency1 : currencies) {
1.35 + for (Currency currency2 : currencies) {
1.36 + if(!currency1.getCurrencyCode().equals(currency2.getCurrencyCode())) {
1.37 + String key = currency1.getCurrencyCode() + currency2.getCurrencyCode();
1.38 + ExchangeRate exchangeRate = exchangeRates.get(key);
1.39 + convertorInstanceExchangeRates.put(key, exchangeRate);
1.40 + }
1.41 + }
1.42 + }
1.43 }
1.44
1.45 /**
1.46 @@ -67,6 +68,18 @@
1.47 exchangeRates.put(key21, new ExchangeRate(currency2, currency1, recountedRate, unit));
1.48
1.49 }
1.50 +
1.51 + /**
1.52 + * Merge exchange rates of actual convertor with exchange rates from selected
1.53 + * convertor. If there are same currencies in both convertors, these from selected
1.54 + * convertor rewrites these in actual convertor.
1.55 + * @param convertor convertor to merge with actual one
1.56 + * @return convertor with merged exchange rates
1.57 + */
1.58 + public Convertor merge(Convertor convertor) {
1.59 + convertorInstanceExchangeRates.putAll(convertor.getInstanceExchangeRates());
1.60 + return this;
1.61 + }
1.62
1.63 /**
1.64 * Creates new instance of convertor.
1.65 @@ -78,11 +91,33 @@
1.66 * @throws UnknownConvertorException
1.67 * thrown if convertor for selected currencies has not been defined
1.68 */
1.69 - public static Convertor getConvertorInstance(Currency currency1, Currency currency2) throws UnknownConvertorException {
1.70 - if (currency1 == null || currency2 == null) {
1.71 - throw new ConvertorException("None of the currencies should be null!!!");
1.72 - }
1.73 - return new Convertor(currency1, currency2);
1.74 + public static Convertor getConvertorInstance(Currency... currencies) throws UnknownConvertorException {
1.75 + List<Currency> currencyList = new ArrayList<Currency>();
1.76 +
1.77 + if(currencies.length < 2) {
1.78 + throw new ConvertorException("To get convertor instance, you have to select at least two currencies!!!");
1.79 + }
1.80 +
1.81 + for (Currency currency1 : currencies) {
1.82 + for (Currency currency2 : currencies) {
1.83 + if(currency1 == null || currency2 == null) {
1.84 + throw new ConvertorException("None of the currencies should be null!!!");
1.85 + }
1.86 +
1.87 + if(!currency1.getCurrencyCode().equals(currency2.getCurrencyCode())) {
1.88 + String key12 = currency1.getCurrencyCode() + currency2.getCurrencyCode();
1.89 + String key21 = currency2.getCurrencyCode() + currency1.getCurrencyCode();
1.90 + if (!(exchangeRates.containsKey(key12) && exchangeRates.containsKey(key21))) {
1.91 + throw new UnknownConvertorException("Selected convertor (" + currency1.getCurrencyCode() + "<->"
1.92 + + currency2.getCurrencyCode() + ") has not defined exchange rates!!!");
1.93 + }
1.94 + }
1.95 + }
1.96 +
1.97 + currencyList.add(currency1);
1.98 + }
1.99 +
1.100 + return new Convertor(currencyList);
1.101 }
1.102
1.103 /**
1.104 @@ -125,25 +160,25 @@
1.105 */
1.106 private ExchangeRate getExchangeRate(Currency originalCurrency, Currency newCurrency) throws InvalidCurrencyException {
1.107 ExchangeRate actualyUsedExchangeRate = null;
1.108 +
1.109 + String key = originalCurrency.getCurrencyCode() + newCurrency.getCurrencyCode();
1.110
1.111 - if (originalCurrency.getCurrencyCode().equals(exchangeRate12.getOriginalCurrency().getCurrencyCode())
1.112 - && newCurrency.getCurrencyCode().equals(exchangeRate12.getNewCurrency().getCurrencyCode())) {
1.113 - actualyUsedExchangeRate = exchangeRate12;
1.114 - } else if (originalCurrency.getCurrencyCode().equals(exchangeRate21.getOriginalCurrency().getCurrencyCode())
1.115 - && newCurrency.getCurrencyCode().equals(exchangeRate21.getNewCurrency().getCurrencyCode())) {
1.116 - actualyUsedExchangeRate = exchangeRate21;
1.117 + if(convertorInstanceExchangeRates.containsKey(key)) {
1.118 + actualyUsedExchangeRate = convertorInstanceExchangeRates.get(key);
1.119 } else {
1.120 - throw new InvalidCurrencyException("This convertor " + this
1.121 - + " could not be used for converting selected currencies (" + originalCurrency.getCurrencyCode() + "->"
1.122 + throw new InvalidCurrencyException("This convertor could not be used for converting selected currencies (" + originalCurrency.getCurrencyCode() + "->"
1.123 + newCurrency.getCurrencyCode() + ") !!!");
1.124 }
1.125
1.126 return actualyUsedExchangeRate;
1.127 }
1.128 -
1.129 - public String toString() {
1.130 - String currency1Code = exchangeRate12.getOriginalCurrency().getCurrencyCode();
1.131 - String currency2Code = exchangeRate12.getNewCurrency().getCurrencyCode();
1.132 - return "Converter [" + currency1Code + "->" + currency2Code + ", " + currency2Code + "->" + currency1Code + "]";
1.133 +
1.134 + /**
1.135 + * Returns exchange rates for actual instance of convertor.
1.136 + * @return exchange rates for actual instance of convertor
1.137 + */
1.138 + Hashtable<String, ExchangeRate> getInstanceExchangeRates() {
1.139 + return convertorInstanceExchangeRates;
1.140 }
1.141 +
1.142 }
2.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
2.2 +++ b/task2/solution12/test/org/apidesign/apifest08/test/Task2Test.java Tue Oct 07 00:17:07 2008 +0200
2.3 @@ -0,0 +1,132 @@
2.4 +package org.apidesign.apifest08.test;
2.5 +
2.6 +import java.util.Currency;
2.7 +
2.8 +import junit.framework.TestCase;
2.9 +
2.10 +import org.apidesign.apifest08.currency.Convertor;
2.11 +import org.apidesign.apifest08.currency.exceptions.UnknownConvertorException;
2.12 +
2.13 +/** There are many currencies around the world and many banks manipulate
2.14 + * with more than one or two at the same time. As banks are usually the
2.15 + * best paying clients, which is true even in case of your Convertor API,
2.16 + * it is reasonable to listen to their requests.
2.17 + * <p>
2.18 + * The quest for today is to enhance your existing convertor API to hold
2.19 + * information about many currencies and allow conversions between any of them.
2.20 + * Also, as conversion rates for diferent currencies usually arise from various
2.21 + * bank departments, there is another important need. There is a need to
2.22 + * compose two convertors into one by merging all the information about
2.23 + * currencies they know about.
2.24 + */
2.25 +public class Task2Test extends TestCase {
2.26 + public Task2Test(String testName) {
2.27 + super(testName);
2.28 + }
2.29 +
2.30 + @Override
2.31 + protected void setUp() throws Exception {
2.32 + }
2.33 +
2.34 + @Override
2.35 + protected void tearDown() throws Exception {
2.36 + }
2.37 +
2.38 + // As in Task1Test, keep in mind, that there are three parts
2.39 + // of the whole system:
2.40 + // 1. there is someone who knows the current exchange rate
2.41 + // 2. there is someone who wants to do the conversion
2.42 + // 3. there is the API between 1. and 2. which allows them to communicate
2.43 + //
2.44 + // Please backward compatibly enhance your existing API to support following
2.45 + // usecases:
2.46 + //
2.47 +
2.48 + /** Create convertor that understands two currencies, CZK and
2.49 + * SKK. Make 100 SKK == 75 CZK. This is method for the group of users that
2.50 + * knows the exchange rate, and needs to use the API to create objects
2.51 + * with the exchange rate. Anyone shall be ready to call this method without
2.52 + * any other method being called previously. The API itself shall know
2.53 + * nothing about any rates, before this method is called.
2.54 + */
2.55 + public static Convertor createTripleConvertor() {
2.56 + // Rates: 1USD = 15CZK
2.57 + // Rates: 1USD = 20SKK
2.58 + // Rates: 75CZK = 100SKK
2.59 + // set exchange rates
2.60 + Convertor.setConvertorRates(Currency.getInstance("USD"), Currency.getInstance("CZK"), 15, 1);
2.61 + Convertor.setConvertorRates(Currency.getInstance("USD"), Currency.getInstance("SKK"), 20, 1);
2.62 + Convertor.setConvertorRates(Currency.getInstance("SKK"), Currency.getInstance("CZK"), 75, 100);
2.63 +
2.64 + // create new instance
2.65 + Convertor convertor = null;
2.66 + try {
2.67 + convertor = Convertor.getConvertorInstance(Currency.getInstance("USD"), Currency.getInstance("SKK"), Currency.getInstance("CZK"));
2.68 + } catch (UnknownConvertorException e) {
2.69 + e.printStackTrace();
2.70 + }
2.71 + return convertor;
2.72 + }
2.73 +
2.74 + /** Define convertor that understands three currencies. Use it.
2.75 + */
2.76 + public void testConvertorForUSDandCZKandSKK() throws Exception {
2.77 + Convertor c = createTripleConvertor();
2.78 +
2.79 + // convert $5 to CZK using c:
2.80 + double result = c.convert(5d, Currency.getInstance("USD"), Currency.getInstance("CZK"));
2.81 + assertEquals("Result is not 75 CZK", 75.0, result);
2.82 +
2.83 + // convert $5 to SKK using c:
2.84 + result = c.convert(5d, Currency.getInstance("USD"), Currency.getInstance("SKK"));
2.85 + assertEquals("Result is not 100 SKK", 100.0, result);
2.86 +
2.87 + // convert 200SKK to CZK using c:
2.88 + result = c.convert(200d, Currency.getInstance("SKK"), Currency.getInstance("CZK"));
2.89 + assertEquals("Result is not 150 CZK", 150.0, result);
2.90 +
2.91 + // convert 200SKK to USK using c:
2.92 + result = c.convert(200d, Currency.getInstance("SKK"), Currency.getInstance("USD"));
2.93 + assertEquals("Result is not 10 USD", 10.0, result);
2.94 + }
2.95 +
2.96 + /** Merge all currency rates of convertor 1 with convertor 2.
2.97 + * Implement this using your API, preferably this method just delegates
2.98 + * into some API method which does the actual work, without requiring
2.99 + * API clients to code anything complex.
2.100 + */
2.101 + public static Convertor merge(Convertor one, Convertor two) {
2.102 + return one.merge(two);
2.103 + }
2.104 +
2.105 + /** Join the convertors from previous task, Task1Test and show that it
2.106 + * can be used to do reasonable conversions.
2.107 + */
2.108 + public void testConvertorComposition() throws Exception {
2.109 + Convertor c = merge(
2.110 + Task1Test.createCZKtoUSD(),
2.111 + Task1Test.createSKKtoCZK()
2.112 + );
2.113 +
2.114 + // convert $5 to CZK using c:
2.115 + double result = c.convert(5d, Currency.getInstance("USD"), Currency.getInstance("CZK"));
2.116 + assertEquals("Result is not 85 CZK", 85.0, result);
2.117 +
2.118 + // convert $8 to CZK using c:
2.119 + result = c.convert(8d, Currency.getInstance("USD"), Currency.getInstance("CZK"));
2.120 + assertEquals("Result is not 136 CZK", 136.0, result);
2.121 +
2.122 + // convert 1003CZK to USD using c:
2.123 + result = c.convert(1003d, Currency.getInstance("CZK"), Currency.getInstance("USD"));
2.124 + assertEquals("Result is not 59 USD", 59.0, result);
2.125 +
2.126 + // convert 16CZK using c:
2.127 + result = c.convert(16d, Currency.getInstance("CZK"), Currency.getInstance("SKK"));
2.128 + assertEquals("Result is not 20 SKK", 20.0, result);
2.129 +
2.130 + // convert 500SKK to CZK using c:
2.131 + result = c.convert(500d, Currency.getInstance("SKK"), Currency.getInstance("CZK"));
2.132 + assertEquals("Result is not 400 CZK", 400.0, result);
2.133 +
2.134 + }
2.135 +}