/// <summary>
/// Fills the cache with Exchange Rates for the given parameters
/// </summary>
/// <param name="startYearMonth">The start yearmonth</param>
/// <param name="endYearMonth">The endyearmonth</param>
/// <param name="currencyFrom">The CurrencyFrom</param>
/// <param name="currencyTo">The CurrencyTo</param>
public void FillExchangeRateCache(YearMonth startYearMonth, YearMonth endYearMonth, int currencyFrom, int currencyTo)
{
try
{
this._StartYearMonth = startYearMonth;
this._EndYearMonth = endYearMonth;
this._CurrencyFrom = currencyFrom;
this._CurrencyTo = currencyTo;
//TODO: Unit test this method
DataTable tableExchangeRates = (this.GetEntity().GetCustomDataSet("FillExchangeRateCache", this)).Tables[0];
foreach (DataRow row in tableExchangeRates.Rows)
{
//Gets the exchange rate from the datarow
BudgetExchangeRate exchangeRate = new BudgetExchangeRate();
exchangeRate.CurrencyFrom = currencyFrom;
exchangeRate.CurrencyTo = currencyTo;
exchangeRate.YearMonth = new YearMonth((int)row["YearMonth"]);
exchangeRate.ExchangeRateValue = (decimal)row["ExchangeRateValue"];
//Add the exchange rate to cache
ExchangeRateCache.InsertExchangeRateToCache(exchangeRate);
}
}
catch (Exception ex)
{
throw new IndException(ex);
}
}
/// <summary>
/// Get the new value expressed in the new currency
/// </summary>
/// <param name="originalValue">the giveen amount expressd in the currencyFrom currency</param>
/// <param name="currencyFrom">The currency for the received amount of money</param>
/// <param name="yearmonth">The yearmonth that will be used the get the new value</param>
/// <param name="currencyTo">The currency that will be used to return the new amount of money</param>
/// <returns>the new amount of money expressed in the currencyTo currency</returns>
internal decimal GetConversionValue(decimal originalValue, int currencyFrom, YearMonth yearmonth, int currencyTo)
{
if (originalValue == 0)
{
return(0);
}
if (originalValue == ApplicationConstants.DECIMAL_NULL_VALUE)
{
return(ApplicationConstants.DECIMAL_NULL_VALUE);
}
//Constructs a new exhcange rate object with the given logical key
BudgetExchangeRate exchangeRate = new BudgetExchangeRate();
exchangeRate.CurrencyFrom = currencyFrom;
exchangeRate.CurrencyTo = currencyTo;
exchangeRate.YearMonth = yearmonth;
//Get the currency rate
decimal currencyRate = this.ExchangeRateCache.GetExchangeRate(exchangeRate);
//Get the converted value
decimal convertedValue = Decimal.Multiply(originalValue, currencyRate);
//return the converted value
return(convertedValue);
}
/// <summary>
/// Returns the exchange Rate value from the cache. If it does not exist it gets it from the database
/// and inset it into cache
/// </summary>
/// <param name="exchangeRate">The exchange rate containing the logical key</param>
/// <returns>The exchange rate value</returns>
internal decimal GetExchangeRate(BudgetExchangeRate exchangeRate)
{
//Search the cache to see if the exchange rate exists in cache
foreach (BudgetExchangeRate currentExchangeRate in exchangeRatesCache)
{
//If it is found return the value from the cache
if (currentExchangeRate.CompareWithObject(exchangeRate))
{
//the object exists in cache but we don't know yet in what order
if (currentExchangeRate.CurrencyFrom == exchangeRate.CurrencyFrom)
{
return(currentExchangeRate.ExchangeRateValue);
}
else
{
return(Decimal.Divide(1, currentExchangeRate.ExchangeRateValue));
}
}
}
//If the code reaches this point, it means that the exchange rate doesn't exists in the cache
//so it should be load from the dabase
decimal exRateValue = (new ExchangeRateReader(this.connectionManager)).GetExchangeRate(exchangeRate);
//After received from the database insert into the cache before return it
exchangeRate.ExchangeRateValue = exRateValue;
this.InsertExchangeRateToCache(exchangeRate);
//Return the exchange Rate value
return(exRateValue);
}
/// <summary>
/// This method returns the exchange rate from the base based on to parameters: Currency and
/// YearMonth; To be known that inside stored procedure two other rules for selecting this ExchangeRate
/// are used. For more information look after Stored Procedure bgtSelectExchangeRateForConverter
/// </summary>
/// <param name="exchangeRate"></param>
/// <returns></returns>
internal decimal GetExchangeRate(BudgetExchangeRate exchangeRate)
{
_CurrencyFrom = exchangeRate.CurrencyFrom;
_CurrencyTo = exchangeRate.CurrencyTo;
_YearMonth = exchangeRate.YearMonth;
DBExchangeRateReader dbc = new DBExchangeRateReader(this.CurrentConnectionManager);
//If for a random reason the specified cast cannot be made, an IndException is thrown
try
{
object returnedER = dbc.ExecuteScalar("bgtSelectExchangeRateForConverter", this);
//TODO: Modifiy error message - use names instead of ids
if (returnedER == DBNull.Value)
{
throw new IndException(ApplicationMessages.MessageWithParameters(ApplicationMessages.EXCEPTION_EXCHANGE_RATE_NOT_FOUND, exchangeRate.CurrencyFrom.ToString(), exchangeRate.CurrencyTo.ToString()));
}
ExchangeRate = (decimal)returnedER;
}
catch (Exception exc)
{
throw new IndException(exc);
}
return(ExchangeRate);
}
/// <summary>
/// Compares the current object with another object
/// </summary>
/// <param name="secondExchangeRate">The object to compare with</param>
/// <returns></returns>
internal bool CompareWithObject(BudgetExchangeRate secondExchangeRate)
{
//All fields except ExchangeRateValue should be the same (no matter in what order)
if (this.YearMonth.GetMonthsDiffrence(secondExchangeRate.YearMonth) != 0)
{
return(false);
}
if ((this.CurrencyFrom == secondExchangeRate.CurrencyFrom) && (this.CurrencyTo == secondExchangeRate.CurrencyTo))
{
return(true);
}
if ((this.CurrencyFrom == secondExchangeRate.CurrencyTo) && (this.CurrencyTo == secondExchangeRate.CurrencyFrom))
{
return(true);
}
return(false);
}
/// <summary>
/// Adds a given exchange rate into cache
/// </summary>
/// <param name="exRate">The exchange rate object</param>
internal void InsertExchangeRateToCache(BudgetExchangeRate exRate)
{
bool found = false;
//Insert the budget exchange rate into the cache only if it is not already in the cache
foreach (BudgetExchangeRate rate in exchangeRatesCache)
{
if (exRate.CompareWithObject(rate))
{
found = true;
break;
}
}
if (!found)
{
exchangeRatesCache.Add(exRate);
}
}