Add formating function to Template in Java Mustache

I have a Java Mustache app and I need to apply a function to render it in currency format

I have my template

{{#currency}}{{number_to_format}}{{/currency}}

And my function

HashMap<String, Object> scopes = new HashMap<String, Object>();

//Add date 
scopes.put("number_to_format",BigDecimal.ONE);
scopes.put("currency", new TemplateFunction() {
          public String apply(String input) {
          	NumberFormat currency = NumberFormat.getCurrencyInstance();
          	return currency.format(new BigDecimal(input));          	          	
              
          }
      }
);

MustacheFactory mf = new DefaultMustacheFactory();
Mustache mustache = mf.compile("template.mustache");
mustache.execute(writer,scopes).flush();

I am unable to get the value in the "input" variable, i always get the variable name "number_to_format". If I return a value in the function it will be rendered.

How can i get the numeric value of my vairable in input?

The input variable is an incoming template, you need to render it to get the value<br/>
Therefore again render it with same factory and scopes and get the value

HashMap<String, Object> scopes = new HashMap<String, Object>();
		
final MustacheFactory mf = new DefaultMustacheFactory();
// Add date
scopes.put("number_to_format", BigDecimal.ONE);
scopes.put("currency", new TemplateFunction() {
	public String apply(String input) {
        //render the input as template to get the value
		Mustache mustache = mf.compile(new StringReader(input), "");
		StringWriter out = new StringWriter();
		mustache.execute(out, scopes);
		
		NumberFormat currency = NumberFormat.getCurrencyInstance(Locale.US);
		return currency.format(new BigDecimal(out.toString()));

	}
});


Mustache mustache = mf.compile("template.mustache");
mustache.execute(new PrintWriter(System.out), scopes).flush();

Otherwise get the value from HashMap by checking the input

if(input.equals("{{number_to_format}}")){
	input = scopes.get("number_to_format").toString();
}

NumberFormat currency = NumberFormat.getCurrencyInstance(Locale.US);
return currency.format(new BigDecimal(input));

Otherwise remove the "{{" and "}}" and use it as a key to hashmap