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Java Introduction to Functional Programming Functional Programming Fundamentals Higher Order Function for Price Conversion

Posted by Anthony Ramnarain
Anthony Ramnarain
8,951 Points

Java Closure Code Challenge

public static Function<Integer, String> getArgentinaPriceConverter() { Locale argLocale = Locale.forLanguageTag("es-AR"); // This fluctuates and is hardcoded temporarily BigDecimal argPesoToUsdRate = new BigDecimal("15.48");

Function<Integer, BigDecimal> usdToArgentinePesoConverter =
  usd -> argPesoToUsdRate.multiply(new BigDecimal(usd));

Function<BigDecimal, String> argentineCurrencyFormatter = price -> {
  Currency currentCurrency = Currency.getInstance(argLocale);
  NumberFormat currencyFormatter =
    NumberFormat.getCurrencyInstance(argLocale);
  return String.format("%s (%s)",
    currencyFormatter.format(price),
    currentCurrency.getDisplayName()
  );
};
return usdToArgentinePesoConverter.andThen(argentineCurrencyFormatter);

}

public static Function<Integer, String> createPriceConverter(Locale locale, BigDecimal usdRate) {

// TODO:  Examine the hardcoded `getArgentinaPriceConverter` method
// TODO:  Using the arguments passed into this method return a function that will work for any locale and rate
return usdPrice -> {
  Currency currentCurrency = Currency.getInstance(locale);
  NumberFormat currencyFormatter = NumberFormat.getCurrencyInstance(locale);
  return String.format("%s (%s)", currencyFormatter.format(usdRate.multiply(new BigDecimal(usdPrice))), currentCurrency.getDisplayName());
};

}

public static Function<Integer, String> createPriceConverter(Locale locale, BigDecimal usdRate) {

// TODO:  Examine the hardcoded `getArgentinaPriceConverter` method
// TODO:  Using the arguments passed into this method return a function that will work for any locale and rate
return usdPrice -> {
  Currency currentCurrency = Currency.getInstance(locale);
  NumberFormat currencyFormatter = NumberFormat.getCurrencyInstance(locale);
  return String.format("%s (%s)", currencyFormatter.format(usdRate.multiply(new BigDecimal(usdPrice))), currentCurrency.getDisplayName());
};

}

Anthony Ramnarain
Anthony Ramnarain
8,951 Points

The error I am receiving java.lang.AssertionError: Expected: is "First is $1.00 (USD) which is $15,48 (Argentine Peso)" but: was "First is $1.00 (USD) which is $ 15,48 (Argentine Peso)"

Unsubscribed User
Unsubscribed User
1,321 Points

I formatted your code so its more readable.

public static Function<Integer, String> getArgentinaPriceConverter() {
Locale argLocale = Locale.forLanguageTag("es-AR"); // This fluctuates and is hardcoded temporarily BigDecimal argPesoToUsdRate = new BigDecimal("15.48");

Function<Integer, BigDecimal> usdToArgentinePesoConverter = usd -> argPesoToUsdRate.multiply(new BigDecimal(usd));

Function<BigDecimal, String> argentineCurrencyFormatter = price -> {
  Currency currentCurrency = Currency.getInstance(argLocale);
  NumberFormat currencyFormatter =
    NumberFormat.getCurrencyInstance(argLocale);
  return String.format("%s (%s)",
    currencyFormatter.format(price),
    currentCurrency.getDisplayName()
  );
};
return usdToArgentinePesoConverter.andThen(argentineCurrencyFormatter);
}

public static Function<Integer, String> createPriceConverter(Locale locale, BigDecimal usdRate) {

// TODO:  Examine the hardcoded `getArgentinaPriceConverter` method
// TODO:  Using the arguments passed into this method return a function that will work for any locale and rate
return usdPrice -> {
  Currency currentCurrency = Currency.getInstance(locale);
  NumberFormat currencyFormatter = NumberFormat.getCurrencyInstance(locale);
  return String.format("%s (%s)", currencyFormatter.format(usdRate.multiply(new BigDecimal(usdPrice))), currentCurrency.getDisplayName());
};
}

public static Function<Integer, String> createPriceConverter(Locale locale, BigDecimal usdRate) {

// TODO:  Examine the hardcoded `getArgentinaPriceConverter` method
// TODO:  Using the arguments passed into this method return a function that will work for any locale and rate
return usdPrice -> {
  Currency currentCurrency = Currency.getInstance(locale);
  NumberFormat currencyFormatter = NumberFormat.getCurrencyInstance(locale);
  return String.format("%s (%s)", currencyFormatter.format(usdRate.multiply(new BigDecimal(usdPrice))), currentCurrency.getDisplayName());
};
}

1 Answer

lukej
lukej
34,222 Points
lukej
lukej
34,222 Points

I get the same AssertionError. You can fix it by adding this line to the getPriceConversionForRecord() method: .replace("$\u00a0", "$"). 

    return String.format("%s is %s (USD) which is %s",
      record.getRegionName(),
      usFormatter.format(record.getCurrentHomeValueIndex()),
      priceConverter.apply(record.getCurrentHomeValueIndex())
    ).replace("$\u00a0", "$");