diff -r 978f6a78c22e -r c6b50876b5cf task4/solution12/src/org/apidesign/apifest08/currency/Convertor.java
--- a/task4/solution12/src/org/apidesign/apifest08/currency/Convertor.java	Fri Oct 17 17:54:38 2008 +0200
+++ /dev/null	Thu Jan 01 00:00:00 1970 +0000
@@ -1,297 +0,0 @@
-package org.apidesign.apifest08.currency;
-
-import java.util.ArrayList;
-import java.util.Calendar;
-import java.util.Currency;
-import java.util.Date;
-import java.util.Hashtable;
-import java.util.List;
-
-import org.apidesign.apifest08.currency.exceptions.ConvertorException;
-import org.apidesign.apifest08.currency.exceptions.InvalidCurrencyException;
-import org.apidesign.apifest08.currency.exceptions.UnknownConvertorException;
-
-/**
- * This is the skeleton class for your API. You need to make it public, so it is accessible to your client code
- * (currently in Task1Test.java) file.
- * <p>
- * Feel free to create additional classes or rename this one, just keep all the API and its implementation in this
- * package. Do not spread it outside to other packages.
- */
-public class Convertor {
-
-  private static Hashtable<String, List<ExchangeRate>> exchangeRates;
-
-  private List<ExchangeRateInstance> exchangeRateInstances;
-
-  /**
-   * Constructor. Checks if all selected currencies are not null and has defined exchange rates for both
-   * directions.
-   * @param currencies currencies for new instance of convertor
-   * @throws UnknownConvertorException if there are not defined exchange rates for both directions for each
-   * pair of currencies
-   */
-  private Convertor(Currency[] currencies) throws UnknownConvertorException {
-    exchangeRateInstances = new ArrayList<ExchangeRateInstance>();
-
-    for (Currency currency1 : currencies) {
-      for (Currency currency2 : currencies) {
-        if(currency1 == null || currency2 == null) {
-          throw new ConvertorException("None of the currencies should be null!!!");
-        }
-          
-        if(!currency1.getCurrencyCode().equals(currency2.getCurrencyCode())) {
-          String key = currency1.getCurrencyCode() + currency2.getCurrencyCode();
-          if (!exchangeRates.containsKey(key)) {
-            throw new UnknownConvertorException("Selected convertor (" + currency1.getCurrencyCode() + "->"
-                + currency2.getCurrencyCode() + ") has not defined exchange rates!!!");
-          }
-          
-          exchangeRateInstances.add(new ExchangeRateInstance(key, null, null));            
-        }
-      }
-    }
-  }
-
-  /**
-   * Sets convertor rate for selected currencies.
-   * @param currency1
-   *          one of the currencies we want to convert to/from
-   * @param currency2
-   *          the other currency
-   * @param rate
-   *          exchange rate from currency1 to currency2
-   * @param unit
-   *          unit of exchangeRate (USD->CZK - unit=1, you exchange one dollar, SKK->CZK unit=100, exchange rate is for
-   *          100SKK)
-   */
-  public static void setConvertorRates(Currency currency1, Currency currency2, double rate, double unit) {
-    if (currency1 == null || currency2 == null) {
-      throw new ConvertorException("None of the currencies should be null!!!");
-    }
-
-    if (rate <= 0 || unit <= 0) {
-      throw new ConvertorException("Rate(" + rate + ") and unit(" + unit + ") has to be grater then zero!!!");
-    }
-
-    if (exchangeRates == null) {
-      exchangeRates = new Hashtable<String, List<ExchangeRate>>();
-    }
-
-    String key12 = currency1.getCurrencyCode() + currency2.getCurrencyCode();
-    String key21 = currency2.getCurrencyCode() + currency1.getCurrencyCode();
-    double recountedRate = (unit / rate) * unit;
-
-    exchangeRates.put(key12, addNewExchangeRate(key12, currency1, currency2, rate, unit, null, null));
-    exchangeRates.put(key21, addNewExchangeRate(key21, currency2, currency1, recountedRate, unit, null, null));
-  }
-  
-  public static Convertor limitExchangeRatesValidity(Convertor convertor, Date validFrom, Date validTo) {
-    if(convertor == null || validFrom == null || validTo == null) {
-      throw new ConvertorException("None of parameters of method limitExchangeRatesValidity should be null!!!");
-    }
-    
-    List<ExchangeRateInstance> exchangeRateInstances = convertor.getExchangeRateInstances();
-    for (ExchangeRateInstance exchangeRateInstance : exchangeRateInstances) {
-      // get actual convertor rates for actual validity
-      ExchangeRate actualExchangeRate = getExchangeRate(exchangeRateInstance.getKey(), exchangeRateInstance.getValidFrom(), exchangeRateInstance.getValidTo());
-      // set new validity for theese rates
-      actualExchangeRate.setValidFrom(validFrom);
-      actualExchangeRate.setValidTo(validTo);
-      // and for selected currency convertor
-      exchangeRateInstance.setValidFrom(validFrom);
-      exchangeRateInstance.setValidTo(substractSecond(validTo));
-    }
-
-    return convertor;
-  }
-  
-  /**
-   * Merge exchange rates of actual convertor with exchange rates from selected 
-   * convertor. If there are same currencies in both convertors, these from selected
-   * convertor rewrites these in actual convertor.
-   * @param convertor convertor to merge with actual one
-   * @return convertor with merged exchange rates 
-   */
-  public Convertor merge(Convertor convertor) {
-    if(convertor == null) {
-      throw new ConvertorException("It's impossible to merge with null convertor!!!");
-    }
-    
-    exchangeRateInstances.addAll(convertor.getExchangeRateInstances());
-	  return this;
-  }
-
-  /**
-   * Creates new instance of convertor.
-   * @param currency1
-   *          one of the currencies we want to convert to/from
-   * @param currency2
-   *          the other currency
-   * @return new instance of convertor
-   * @throws UnknownConvertorException
-   *           thrown if convertor for selected currencies has not been defined
-   */
-  public static Convertor getConvertorInstance(Currency... currencies) throws UnknownConvertorException {
-   	if(currencies.length < 2) {
-   		throw new ConvertorException("To get convertor instance, you have to select at least two currencies!!!");
-   	}
-    
-    return new Convertor(currencies);
-  }
-
-  /**
-   * Converts selected amout of selected currency to other currency of this convertor instance.
-   * @param amount
-   *          amount to convert
-   * @param originalCurrency
-   *          currency of this amount
-   * @param newCurrency
-   *          currency to which we want convert
-   * @return converted amount
-   * @throws InvalidCurrencyException
-   *           while one or both currencies doesn't fit for this convertor
-   */
-  public double convert(double amount, Currency originalCurrency, Currency newCurrency) throws InvalidCurrencyException {
-    ExchangeRate actualyUsedExchangeRate = null;
-
-    if (originalCurrency == null) {
-      throw new ConvertorException("Original currency is null!!!");
-    }
-
-    if (newCurrency == null) {
-      throw new ConvertorException("Destination currency is null!!!");
-    }
-
-    actualyUsedExchangeRate = getExchangeRate(originalCurrency, newCurrency);
-
-    return countResult(actualyUsedExchangeRate, amount);
-  }
-
-  private double countResult(ExchangeRate actualyUsedExchangeRate, double amount) {
-    return amount * actualyUsedExchangeRate.getRate() / actualyUsedExchangeRate.getUnit();
-  }
-
-  /**
-   * Decides the direction of conversion and returns actual exchange rate
-   * for selected currencies and actual moment.
-   * @param actualCurrency
-   *          actual currency we want to convert
-   * @return actual exchange rate of this convertor for selected currency
-   */
-  private ExchangeRate getExchangeRate(Currency originalCurrency, Currency newCurrency) throws InvalidCurrencyException {
-    ExchangeRate actualyUsedExchangeRate = null;
-    
-    String key = originalCurrency.getCurrencyCode() + newCurrency.getCurrencyCode();
-
-    ExchangeRateInstance exchangeRateInstance = findExchangeRateInstance(key);
-    if(exchangeRateInstance != null) {
-      actualyUsedExchangeRate = getExchangeRate(exchangeRateInstance.getKey(), exchangeRateInstance.getValidFrom(), exchangeRateInstance.getValidTo());
-    } else {
-      throw new InvalidCurrencyException("This convertor could not be used for converting selected currencies (" + originalCurrency.getCurrencyCode() + "->"
-          + newCurrency.getCurrencyCode() + ") !!!");
-    }
-
-    return actualyUsedExchangeRate;
-  }
-  
-  /**
-   * Finds instance of exchange rate for actual instance of convertor and actual moment.
-   * @param key exchange rate instance key
-   * @return exchange rate instance
-   */
-  private ExchangeRateInstance findExchangeRateInstance(String key) {
-    ExchangeRateInstance instance = null;
-    
-    Date now = new Date();
-    for (ExchangeRateInstance item : exchangeRateInstances) {
-      if(item.getKey().equals(key) && item.getValidFrom() == null && item.getValidTo() == null) {
-        instance = item;
-        break;
-      } else if(item.getKey().equals(key) && item.getValidFrom().compareTo(now) <= 0 && item.getValidTo().compareTo(now) >= 0) {
-        instance = item;
-        break;
-      }
-    }
-    
-    return instance;
-  }
-  
-  
-  /**
-   * Returns currency convertors for actual instance of convertor.
-   * @return currency convertors for actual instance of convertor
-   */
-  private List<ExchangeRateInstance> getExchangeRateInstances() {
-    return exchangeRateInstances;
-  }
-  
-  private static ExchangeRate getExchangeRate(String key, Date validFrom, Date validTo) {
-    ExchangeRate exchangeRate = null;
-    
-    List<ExchangeRate> currencyExchangeRates = exchangeRates.get(key);
-    for (ExchangeRate currencyExchangeRate : currencyExchangeRates) {
-      Date actValidFrom = currencyExchangeRate.getValidFrom();
-      Date actValidTo = currencyExchangeRate.getValidTo();
-      
-      if(actValidFrom == null && validFrom == null && actValidTo == null && validTo == null) {
-        exchangeRate = currencyExchangeRate;
-        break;
-      } else if(actValidFrom != null && validFrom != null && actValidTo != null && validTo != null && actValidFrom.compareTo(validFrom) <= 0 && actValidTo.compareTo(validTo) > 0) {
-        exchangeRate = currencyExchangeRate;
-        break;
-      }
-    }
-    
-    if(exchangeRate == null) {
-      throw new ConvertorException("Exchange rate for actual exchange rate instance not found!!!");
-    }
-    
-    return exchangeRate;
-  }
-  
-  private static List<ExchangeRate> addNewExchangeRate(String key, Currency currency1, Currency currency2, double rate, double unit, Date validFrom, Date validTo) {
-    List<ExchangeRate> actualExchangeRates = new ArrayList<ExchangeRate>();
-    ExchangeRate newExchangeRate = null;
-    
-    if(exchangeRates.containsKey(key)) {
-      List<ExchangeRate> rates = exchangeRates.get(key);
-      for (ExchangeRate exchangeRate : rates) {
-        if(exchangeRate.getValidFrom() == null && exchangeRate.getValidTo() == null && validFrom == null && validTo == null) {
-          newExchangeRate = exchangeRate;
-          break;
-        } else if(exchangeRate.getValidFrom() != null && exchangeRate.getValidTo() != null && validFrom != null && validTo != null) {
-          if(exchangeRate.getValidFrom().compareTo(validFrom) == 0 && exchangeRate.getValidTo().compareTo(validTo) == 0) {
-            newExchangeRate = exchangeRate;
-            break;
-          }
-        }
-      }
-      actualExchangeRates.addAll(rates);
-    }
-    
-    if(newExchangeRate == null) {
-      actualExchangeRates.add(new ExchangeRate(currency1, currency2, rate, unit, validFrom, validTo));
-    } else {
-      newExchangeRate.setRate(rate);
-      newExchangeRate.setUnit(unit);
-      actualExchangeRates.add(newExchangeRate);
-    }
-    
-    return actualExchangeRates;
-  }
-  
-  /**
-   * Substracts one second from selected date.
-   * @param date date
-   * @return date -1s
-   */
-  private static Date substractSecond(Date date) {
-    Calendar calendar = Calendar.getInstance();
-    calendar.setTime(date);
-    calendar.set(Calendar.SECOND, -1);
-    
-    return calendar.getTime();
-  }
-  
-}