It it possible to have multiple Locales in one same MessageFormat?

Question

I have the following JSON example below:

{
    "value": 946.2,
    "description": "O valor é R$ 946,20."
}

I need to use MessageFormat to JUnit test this JSON example, but I get an invalid value because my Locale is not in english. If I change my Locale to english instead of brazilian portuguese I get an invalid description because the currency value is displayed in English.

Here's my code:

import java.math.BigDecimal;
import java.text.MessageFormat;
import java.util.Locale;

Locale.setDefault(Locale.ENGLISH);

System.out.println(MessageFormat.format("""
'{'
    "value": {0},
    "description": "O valor é {0,number,currency}."
'}'
""", new BigDecimal(946.2)));

How can I format the value or the description in order to get the JSON as displayed above?

Answer 1

This is a String.format solution with two inner (localized, customized) NumberFormatters:

import java.math.BigDecimal;
import java.text.NumberFormat;
import java.util.Locale;

public class OtherMain {

  private static final Locale LOCALE_PT_BR = new Locale.Builder().
      setLanguage("pt").
      setRegion("BR").
      build();
  
  private static final NumberFormat DEFAULT_NUMBER_FMT
      = NumberFormat.getNumberInstance(Locale.US);
  private static final NumberFormat MY_SPECIAL_NUMBER_FMT
      = NumberFormat.getCurrencyInstance(LOCALE_PT_BR);

  static {
    // this disables "thousands sperarator", we can adjust DEFAULT_NUMBER_FMT as well...
    MY_SPECIAL_NUMBER_FMT.setGroupingUsed(false);
  }

  public static void main(String[] args) {
    final BigDecimal num = new BigDecimal(99946.2);
    System.out.format("""
                      {
                        "value": %s,
                        "description": "O valor é %s."
                      }
                      """,
        DEFAULT_NUMBER_FMT.format(num),
        MY_SPECIAL_NUMBER_FMT.format(num)
    );
  }
}

Prints:

{
  "value": 99,946.2,
  "description": "O valor é R$ 99946,20."
}