@Override
	public NumberFormat convertFromText(String value, Class<?> targetType, String optionContext) {
		if (DEFAULT.equals(value)) {
			return NumberFormat.getInstance();
		}
		else {
			return new DecimalFormat(value);
		}
	}
Knows how to convert from a String to a new {@link NumberFormat} instance.

@author Eric Bottard
spring-xd-shell/src/main/java/org/springframework/xd/shell/converter/NumberFormatConverter.java