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Java

Posted by Liam Cassidy
Liam Cassidy
9,739 Points

Java Closures Excersise

Hello,

I solved the closures exercise with the following solution:

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(usdPrice), currentCurrency.getDisplayName());
    };
  }

However, I am confused with my solution. My solution seems to only return a function that formats the current price into a locale format and displays that current currency. Yet, the function name is createPriceConverter. I feel that I may have missed an operation in here on manipulating the usdRate yet the tests did not catch this. Or, perhaps the function name should be different (e.g. "getCurrencyFormatter").

Any feedback on what I am missing is most welcome.

Cheers,

Liam

2 Answers

Fahad Mutair
Fahad Mutair
10,359 Points

hi Liam Cassidy , you are missed multiplication to change from Peso to Usd , you can solve it in this way

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());
    };
}
Liam Cassidy
Liam Cassidy
9,739 Points

Thanks, Fahad. Much appreciated!

Ben Basty
Ben Basty
23,772 Points
Ben Basty
Ben Basty
23,772 Points

Have anyone came into this error : Expected: a string containing "1,00 (Euro)" but: was "1,00 € (Euro)" Here is how i resolved it.

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);
      if (currencyFormatter instanceof DecimalFormat) {
        DecimalFormat df = (DecimalFormat) currencyFormatter;

        DecimalFormatSymbols dfs = df.getDecimalFormatSymbols();

        dfs.setCurrencySymbol("");

        df.setDecimalFormatSymbols(dfs);

        df.applyPattern(".00");

      }
      return String.format("%s (%s)", currencyFormatter.format(usdRate), currentCurrency.getDisplayName()
      );
    };
  }

Don't forget to import 

import java.text.DecimalFormat;
import java.text.DecimalFormatSymbols;