Named placeholders in string formatting

Question

In Python, when formatting string, I can fill placeholders by name rather than by position, like that:

print \"There\'s an incorrect value \'%(value)s\' in c         


        

Answer 1

Based on the answer I created MapBuilder class:

public class MapBuilder {

    public static Map build(Object... data) {
        Map result = new LinkedHashMap<>();

        if (data.length % 2 != 0) {
            throw new IllegalArgumentException("Odd number of arguments");
        }

        String key = null;
        Integer step = -1;

        for (Object value : data) {
            step++;
            switch (step % 2) {
                case 0:
                    if (value == null) {
                        throw new IllegalArgumentException("Null key value");
                    }
                    key = (String) value;
                    continue;
                case 1:
                    result.put(key, value);
                    break;
            }
        }

        return result;
    }

}

then I created class StringFormat for String formatting:

public final class StringFormat {

    public static String format(String format, Object... args) {
        Map values = MapBuilder.build(args);

        for (Map.Entry entry : values.entrySet()) {
            String key = entry.getKey();
            Object value = entry.getValue();
            format = format.replace("$" + key, value.toString());
        }

        return format;
    }

}

which you could use like that:

String bookingDate = StringFormat.format("From $startDate to $endDate"), 
        "$startDate", formattedStartDate, 
        "$endDate", formattedEndDate
);