MonetaryConversions.getConversion loosing rate date for exchange rate providers

l-ray commented 2 years ago

Following the example to retrieve conversion rates for a given historic point in time

Money
    .of(BigDecimal.TEN, "EUR")
    .with(
      MonetaryConversions.getConversion(
          ConversionQueryBuilder.of()
        .setTermCurrency("USD")
        .set(LocalDate.of(2015, 1, 5))
        .build()
      )
)

the LocalDate information is lost within calling MonetaryConversions.getConversion (calling MonetaryConversions#getMonetaryConversionsSpi().getConversion(conversionQuery) -> calling MonetaryConversionsSingletonSpi#getConversion(ConversionQuery conversionQuery))

The code fragment in question is

    default CurrencyConversion getConversion(ConversionQuery conversionQuery) {
        return this.getExchangeRateProvider(conversionQuery).getCurrencyConversion((CurrencyUnit)Objects.requireNonNull(conversionQuery.getCurrency(), "Terminating Currency is required."));
    }

With a custom exchange rate provider, the issue manifests in

public class CustomExchangeRateProvider extends AbstractRateProvider {
   ...
       @Override
    public ExchangeRate getExchangeRate(ConversionQuery conversionQuery) {
        CurrencyUnit baseCurrency = conversionQuery.getBaseCurrency();
        CurrencyUnit currency = conversionQuery.getCurrency();
        LocalDate aDate = conversionQuery.get(LocalDate.class); // <- NullPointerException
        return ...;
    }
   ...
}

With the OTB exchange rate providers, it seems to work as those use the current LocalDate as fallback. I wrote the following test, that fails accordingly (minimal reproduceable example at https://github.com/l-ray/javamoney-poc/)

       @Test
    void selectsFromECBWithGivenDate() {
        MonetaryAmount inEUR = Money.of(BigDecimal.TEN, "EUR");

        CurrencyConversion conv2 = MonetaryConversions.getConversion(ConversionQueryBuilder.of()
                .setProviderName("ECB-HIST")
                .setTermCurrency("USD")
                .set(LocalDate.now())
                .build());

        CurrencyConversion conv1 = MonetaryConversions.getConversion(
                ConversionQueryBuilder.of()
                        .setProviderName("ECB-HIST")
                        .setTermCurrency("USD")
                        .set(LocalDate.of(2008, 1, 1))
                        .build()
        );

        assertEquals(inEUR.with(conv1), inEUR.with(conv1));
        assertEquals(inEUR.with(conv2), inEUR.with(conv2));
        assertNotEquals(inEUR.with(conv1), inEUR.with(conv2)); // <- failing step
    }

Hope, this is helpful.

keilw commented 2 years ago

Does that example contain relevant parts of the custom provider? Either way, with all those classes like Money, the ticket clearly does not belong to the API, will try to relocate it, if we can.

l-ray commented 2 years ago

Thanks for the super fast response.

The example basically holds the unit test from above as maven project and github actions - to easily see the failing test. I opened the issue here as IMO the source of the issue might be javax.money.spi.MonetaryConversionsSingletonSpi

This said, feel free .... whatever is the best location in your opinion. Again, thanks for the fast pick-up.