japod@6: package org.apidesign.apifest08.currency;
japod@6: 
japod@37: import java.util.ArrayList;
japod@37: import java.util.Collection;
japod@37: import java.util.HashSet;
japod@37: import java.util.List;
japod@37: import java.util.Set;
japod@6: import org.apidesign.apifest08.currency.Computer.ComputerRequest;
japod@6: import org.apidesign.apifest08.currency.Computer.ComputerResponse;
japod@6: 
japod@6: /**
japod@6:  * Convertor.
japod@6:  * 
japod@6:  * In Task 1's version provides conversion between currency values
japod@6:  * with amount stored in integer or double, that are identified
japod@6:  * with string value. Exchange rates are immutable.
japod@6:  * 
japod@37:  * In Task2's version provides support for multiple exchange rates
japod@37:  * between different currencies & merging exchange rates from
japod@37:  * existing convertors into new convertor's instance.
japod@37:  * No time for javadoc these features, sorry.
japod@37:  * 
japod@53:  * In Task3's version supports reading of current exchange rates
japod@53:  * from data sources. Data sources are merged during convertors' merging
japod@53:  * as well as static exchange rates.
japod@53:  * No time for javadoc, again.
japod@53:  * 
japod@6:  * @author ked
japod@6:  */
japod@6: public final class Convertor<AmountType, IdentifierType> {
japod@6: 
japod@6:     Computer<AmountType> computer;
japod@53:     // each static exchange rate could be a special case of an exchange rate data source
japod@37:     List<ExchangeRateValue<AmountType, IdentifierType>> exchangeRates = new ArrayList<ExchangeRateValue<AmountType, IdentifierType>>();
japod@53:     List<ExchangeRateDataSource<AmountType, IdentifierType>> exchangeRateDataSources = new ArrayList<ExchangeRateDataSource<AmountType, IdentifierType>>();
japod@6: 
japod@53:     Convertor(Computer<AmountType> computer) {
japod@37:         this.computer = computer;
japod@53:     }
japod@53:     
japod@53:     void addExchangeRates(Collection<ExchangeRateValue<AmountType, IdentifierType>> exchangeRates) {
japod@37:         for (ExchangeRateValue<AmountType, IdentifierType> exchangeRate : exchangeRates) {
japod@53:             if (isExchangeRate(
japod@37:                     exchangeRate.getCurrencyA().getIdentifier(),
japod@53:                     exchangeRate.getCurrencyB().getIdentifier())) {
japod@37:                 throw new IllegalArgumentException("Duplicate exchange rate!");
japod@37:             }
japod@37:             this.exchangeRates.add(exchangeRate);
japod@19:         }
japod@37:     }
japod@53:     
japod@53:     void addExchangeRateDataSources(Collection<ExchangeRateDataSource<AmountType, IdentifierType>> exchangeRateDataSources) {
japod@53:         for (ExchangeRateDataSource<AmountType, IdentifierType> exchangeRateDataSource : exchangeRateDataSources) {
japod@53:             if (isExchangeRate(
japod@53:                     exchangeRateDataSource.getCurrencyAIdentifier(),
japod@53:                     exchangeRateDataSource.getCurrencyBIdentifier())) {
japod@53:                 throw new IllegalArgumentException("Duplicate exchange rate!");
japod@53:             }
japod@53:             this.exchangeRateDataSources.add(exchangeRateDataSource);
japod@53:         }
japod@53:     }
japod@53:     
japod@53:     ExchangeRateValue<AmountType, IdentifierType> findExchangeRate(
japod@37:             IdentifierType currencyA,
japod@37:             IdentifierType currencyB) {
japod@37:         for (ExchangeRateValue<AmountType, IdentifierType> exchangeRate : exchangeRates) {
japod@37:             if ((exchangeRate.getCurrencyA().getIdentifier().equals(currencyA) && exchangeRate.getCurrencyB().getIdentifier().equals(currencyB)) ||
japod@37:                     (exchangeRate.getCurrencyA().getIdentifier().equals(currencyB) && exchangeRate.getCurrencyB().getIdentifier().equals(currencyA))) {
japod@37:                 return exchangeRate;
japod@37:             }
japod@37:         }
japod@53:         for (ExchangeRateDataSource<AmountType, IdentifierType> exchangeRateDataSource : exchangeRateDataSources) {
japod@53:             if ((exchangeRateDataSource.getCurrencyAIdentifier().equals(currencyA) && exchangeRateDataSource.getCurrencyBIdentifier().equals(currencyB)) ||
japod@53:                     (exchangeRateDataSource.getCurrencyAIdentifier().equals(currencyB) && exchangeRateDataSource.getCurrencyBIdentifier().equals(currencyA))) {
japod@53:                 return exchangeRateDataSource.getExchangeRate();
japod@53:             }
japod@53:         }
japod@37:         return null;
japod@6:     }
japod@53:     
japod@53:     boolean isExchangeRate(
japod@53:             IdentifierType currencyA,
japod@53:             IdentifierType currencyB) {
japod@53:         for (ExchangeRateValue<AmountType, IdentifierType> exchangeRate : exchangeRates) {
japod@53:             if ((exchangeRate.getCurrencyA().getIdentifier().equals(currencyA) && exchangeRate.getCurrencyB().getIdentifier().equals(currencyB)) ||
japod@53:                     (exchangeRate.getCurrencyA().getIdentifier().equals(currencyB) && exchangeRate.getCurrencyB().getIdentifier().equals(currencyA))) {
japod@53:                 return true;
japod@53:             }
japod@53:         }
japod@53:         for (ExchangeRateDataSource<AmountType, IdentifierType> exchangeRateDataSource : exchangeRateDataSources) {
japod@53:             if ((exchangeRateDataSource.getCurrencyAIdentifier().equals(currencyA) && exchangeRateDataSource.getCurrencyBIdentifier().equals(currencyB)) ||
japod@53:                     (exchangeRateDataSource.getCurrencyAIdentifier().equals(currencyB) && exchangeRateDataSource.getCurrencyBIdentifier().equals(currencyA))) {
japod@53:                 return true;
japod@53:             }
japod@53:         }
japod@53:         return false;
japod@53:     }
japod@6: 
japod@6:     /**
japod@6:      * Convert an amount of the one currency to an amount of the another one currency
japod@37:      * with respect to previously specified exchange rates.
japod@6:      * 
japod@19:      * @param targetCurrency an identifier of the requested currency
japod@19:      * @param currencyValue an amount of the another one currency
japod@19:      * @return an amount of the requested currency
japod@6:      */
japod@19:     public CurrencyValue<AmountType, IdentifierType> convert(
japod@19:             IdentifierType targetCurrency,
japod@19:             CurrencyValue<AmountType, IdentifierType> currencyValue) {
japod@37:         ExchangeRateValue<AmountType, IdentifierType> exchangeRate =
japod@53:                 findExchangeRate(currencyValue.getIdentifier(), targetCurrency);
japod@37:         if (exchangeRate == null) {
japod@19:             throw new IllegalArgumentException("Inappropriate currencies to convert!");
japod@6:         }
japod@37: 
japod@37:         ComputerRequest<AmountType> computerRequest = new ComputerRequest<AmountType>();
japod@37:         computerRequest.setInput(currencyValue.getAmount());
japod@37: 
japod@37:         IdentifierType targetCurrencyRef; // just for backward compatibility :-(
japod@37:         if (exchangeRate.getCurrencyA().getIdentifier().equals(targetCurrency)) {
japod@37:             computerRequest.setInputCurrencyRatio(exchangeRate.getCurrencyB().getAmount());
japod@37:             computerRequest.setOutputCurrencyRatio(exchangeRate.getCurrencyA().getAmount());
japod@37:             targetCurrencyRef = exchangeRate.getCurrencyA().getIdentifier();
japod@37:         } else {
japod@37:             computerRequest.setInputCurrencyRatio(exchangeRate.getCurrencyA().getAmount());
japod@37:             computerRequest.setOutputCurrencyRatio(exchangeRate.getCurrencyB().getAmount());
japod@37:             targetCurrencyRef = exchangeRate.getCurrencyB().getIdentifier();
japod@37:         }
japod@37: 
japod@53:         ComputerResponse<AmountType> computerResponse = new ComputerResponse<AmountType>();
japod@53:         computer.compute(computerRequest, computerResponse);
japod@53: 
japod@37:         return CurrencyValue.getCurrencyValue(
japod@37:                 computerResponse.getResult(),
japod@37:                 targetCurrencyRef);
japod@37:     }
japod@37: 
japod@37:     // ---
japod@37:     // MERGING
japod@37:     // ---
japod@37:     static <AmountType, IdentifierType> Convertor<AmountType, IdentifierType> mergeConvertors(
japod@37:             Computer<AmountType> computer,
japod@37:             Collection<Convertor<AmountType, IdentifierType>> convertors) {
japod@37:         Set<ExchangeRateValue<AmountType, IdentifierType>> exchangeRatesSet = new HashSet<ExchangeRateValue<AmountType, IdentifierType>>();
japod@53:         Set<ExchangeRateDataSource<AmountType, IdentifierType>> exchangeRateDataSourcesSet = new HashSet<ExchangeRateDataSource<AmountType, IdentifierType>>();
japod@37:         for (Convertor<AmountType, IdentifierType> convertor : convertors) {
japod@37:             exchangeRatesSet.addAll(convertor.exchangeRates);
japod@37:         }
japod@53:         for (Convertor<AmountType, IdentifierType> convertor : convertors) {
japod@53:             exchangeRateDataSourcesSet.addAll(convertor.exchangeRateDataSources);
japod@53:         }
japod@53:         
japod@53:         Convertor<AmountType, IdentifierType> c = new Convertor<AmountType, IdentifierType>(computer);
japod@53:         c.addExchangeRates(exchangeRatesSet);
japod@53:         c.addExchangeRateDataSources(exchangeRateDataSourcesSet);
japod@53:         return c;
japod@37:     }
japod@37: 
japod@37:     static <AmountType, IdentifierType> Convertor<AmountType, IdentifierType> mergeConvertors(
japod@37:             Computer<AmountType> computer,
japod@37:             Convertor<AmountType, IdentifierType> convertorA,
japod@37:             Convertor<AmountType, IdentifierType> convertorB) {
japod@37:         Collection<Convertor<AmountType, IdentifierType>> convertors =
japod@37:                 new ArrayList<Convertor<AmountType, IdentifierType>>();
japod@37:         convertors.add(convertorA);
japod@37:         convertors.add(convertorB);
japod@37:         return mergeConvertors(computer, convertors);
japod@37:     }
japod@37: 
japod@37:     public static Convertor<Double, String> mergeConvertorsDoubleString(
japod@37:             Collection<Convertor<Double, String>> convertors) {
japod@37:         return mergeConvertors(DoubleComputer, convertors);
japod@37:     }
japod@37: 
japod@37:     public static Convertor<Double, String> mergeConvertorsDoubleString(
japod@37:             Convertor<Double, String> convertorA,
japod@37:             Convertor<Double, String> convertorB) {
japod@37:         return mergeConvertors(DoubleComputer, convertorA, convertorB);
japod@37:     }
japod@37: 
japod@37:     public static Convertor<Integer, String> mergeConvertorsIntegerString(
japod@37:             Collection<Convertor<Integer, String>> convertors) {
japod@37:         return mergeConvertors(IntegerComputer, convertors);
japod@37:     }
japod@37: 
japod@37:     public static Convertor<Integer, String> mergeConvertorsIntegerString(
japod@37:             Convertor<Integer, String> convertorA,
japod@37:             Convertor<Integer, String> convertorB) {
japod@37:         return mergeConvertors(IntegerComputer, convertorA, convertorB);
japod@37:     }
japod@37: 
japod@37:     // ---
japod@37:     // CREATION
japod@37:     // ---
japod@37:     static <AmountType, IdentifierType> Convertor<AmountType, IdentifierType> getConvertor(
japod@37:             Computer<AmountType> computer, Collection<ExchangeRateValue<AmountType, IdentifierType>> exchangeRates) {
japod@53:         Convertor<AmountType, IdentifierType> c = new Convertor<AmountType, IdentifierType>(computer);
japod@53:         c.addExchangeRates(exchangeRates);
japod@53:         return c;
japod@6:     }
japod@6: 
japod@53:     static <AmountType, IdentifierType> Convertor<AmountType, IdentifierType> getConvertorDataSource(
japod@53:             Computer<AmountType> computer, Collection<ExchangeRateDataSource<AmountType, IdentifierType>> exchangeRateDataSources) {
japod@53:         Convertor<AmountType, IdentifierType> c = new Convertor<AmountType, IdentifierType>(computer);
japod@53:         c.addExchangeRateDataSources(exchangeRateDataSources);
japod@53:         return c;
japod@53:     }
japod@53:     
japod@6:     static <AmountType, IdentifierType> Convertor<AmountType, IdentifierType> getConvertor(
japod@37:             Computer<AmountType> computer, ExchangeRateValue<AmountType, IdentifierType> exchangeRate) {
japod@37:         Collection<ExchangeRateValue<AmountType, IdentifierType>> exchangeRates =
japod@37:                 new ArrayList<ExchangeRateValue<AmountType, IdentifierType>>();
japod@37:         exchangeRates.add(exchangeRate);
japod@37:         return getConvertor(computer, exchangeRates);
japod@6:     }
japod@6:     
japod@53:     static <AmountType, IdentifierType> Convertor<AmountType, IdentifierType> getConvertorDataSource(
japod@53:             Computer<AmountType> computer, ExchangeRateDataSource<AmountType, IdentifierType> exchangeRateDataSource) {
japod@53:         Collection<ExchangeRateDataSource<AmountType, IdentifierType>> exchangeRateDataSources =
japod@53:                 new ArrayList<ExchangeRateDataSource<AmountType, IdentifierType>>();
japod@53:         exchangeRateDataSources.add(exchangeRateDataSource);
japod@53:         return getConvertorDataSource(computer, exchangeRateDataSources);
japod@53:     }
japod@53:     
japod@37:     public static Convertor<Double, String> getConvertorDoubleString(
japod@37:             Collection<ExchangeRateValue<Double, String>> exchangeRates) {
japod@37:         return getConvertor(DoubleComputer, exchangeRates);
japod@37:     }
japod@6: 
japod@37:     public static Convertor<Double, String> getConvertorDoubleString(
japod@37:             ExchangeRateValue<Double, String> exchangeRate) {
japod@37:         return getConvertor(DoubleComputer, exchangeRate);
japod@37:     }
japod@53:     
japod@53:     public static Convertor<Double, String> getConvertorDataSourceDoubleString(
japod@53:             Collection<ExchangeRateDataSource<Double, String>> exchangeRateDataSources) {
japod@53:         return getConvertorDataSource(DoubleComputer, exchangeRateDataSources);
japod@53:     }
japod@6: 
japod@53:     public static Convertor<Double, String> getConvertorDataSourceDoubleString(
japod@53:             ExchangeRateDataSource<Double, String> exchangeRateDataSource) {
japod@53:         return getConvertorDataSource(DoubleComputer, exchangeRateDataSource);
japod@53:     }
japod@53:     
japod@37:     public static Convertor<Integer, String> getConvertorIntegerString(
japod@37:             Collection<ExchangeRateValue<Integer, String>> exchangeRates) {
japod@37:         return getConvertor(IntegerComputer, exchangeRates);
japod@37:     }
japod@37: 
japod@37:     public static Convertor<Integer, String> getConvertorIntegerString(
japod@37:             ExchangeRateValue<Integer, String> exchangeRate) {
japod@37:         return getConvertor(IntegerComputer, exchangeRate);
japod@37:     }
japod@53:     
japod@53:     public static Convertor<Integer, String> getConvertorDataSourceIntegerString(
japod@53:             Collection<ExchangeRateDataSource<Integer, String>> exchangeRateDataSources) {
japod@53:         return getConvertorDataSource(IntegerComputer, exchangeRateDataSources);
japod@53:     }
japod@53: 
japod@53:     public static Convertor<Integer, String> getConvertorDataSourceIntegerString(
japod@53:             ExchangeRateDataSource<Integer, String> exchangeRateDataSource) {
japod@53:         return getConvertorDataSource(IntegerComputer, exchangeRateDataSource);
japod@53:     }
japod@37: 
japod@37:     // ---
japod@37:     // BACKWARD COMPATIBILITY - CREATION
japod@37:     // ---
japod@6:     /**
japod@6:      * Creates convertor for Double|String values with specified exchange rate
japod@6:      * between two currencies.
japod@6:      * 
japod@6:      * @param firstCurrencyExchangeRate first currency
japod@6:      * @param secondCurrencyExchangeRate second currency
japod@6:      * @return convertor
japod@6:      */
japod@6:     public static Convertor<Double, String> getConvertorDoubleString(
japod@6:             CurrencyValue<Double, String> firstCurrencyExchangeRate,
japod@6:             CurrencyValue<Double, String> secondCurrencyExchangeRate) {
japod@37:         return getConvertorDoubleString(ExchangeRateValue.getExchangeRate(firstCurrencyExchangeRate, secondCurrencyExchangeRate));
japod@6:     }
japod@6: 
japod@6:     /**
japod@6:      * Creates convertor for Integer|String values with specified exchange rate
japod@6:      * between two currencies.
japod@6:      * 
japod@6:      * @param firstCurrencyExchangeRate first currency
japod@6:      * @param secondCurrencyExchangeRate second currency
japod@6:      * @return convertor
japod@6:      */
japod@6:     public static Convertor<Integer, String> getConvertorIntegerString(
japod@6:             CurrencyValue<Integer, String> firstCurrencyExchangeRate,
japod@6:             CurrencyValue<Integer, String> secondCurrencyExchangeRate) {
japod@37:         return getConvertorIntegerString(ExchangeRateValue.getExchangeRate(firstCurrencyExchangeRate, secondCurrencyExchangeRate));
japod@6:     }
japod@37:     
japod@37:     // ---
japod@37:     // COMPUTERS
japod@37:     // ---
japod@37:     static final Computer<Double> DoubleComputer = new Computer<Double>() {
japod@37: 
japod@53:         public void compute(ComputerRequest<Double> request, ComputerResponse<Double> response) {
japod@37:             response.setResult(request.getInput() * request.getOutputCurrencyRatio() / request.getInputCurrencyRatio());
japod@37:         }
japod@37:     };
japod@37:     static final Computer<Integer> IntegerComputer = new Computer<Integer>() {
japod@37: 
japod@53:         public void compute(ComputerRequest<Integer> request, ComputerResponse<Integer> response) {
japod@37:             response.setResult(request.getInput() * request.getOutputCurrencyRatio() / request.getInputCurrencyRatio());
japod@37:         }
japod@37:     };
japod@6: }