XmlInColorsConverter

XmlInColorsConverter.java

import java.io.File;
import java.io.IOException;
import java.util.Scanner;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
import java.util.stream.Collectors;
import java.util.stream.IntStream;

public class XmlInColorsConverter {
    private static final Pattern NAME = Pattern.compile("(?:([a-zA-Z][a-zA-Z0-9]+):)?([a-zA-Z][a-zA-Z0-9._]+)");
    private static final Pattern VAL = Pattern.compile("\"((?:[^\"]|(?<=\\\\)\")*)\"");
    private static final Pattern ATTR = Pattern.compile("(" + NAME + ")\\s*(=)\\s*(" + VAL + ")\\s*");
    private static final Pattern MARKUP = Pattern.compile("(\\s*)(<)(/|\\?)?" + NAME + "\\s*(?:" + ATTR + ")*(/|\\?)?>");

    private static final String NORMAL = "\033[0m";
    private static final String YELLOW = "\033[1;33m";
    private static final String BLUE = "\033[34m";
    private static final String PINK = "\033[35m";
    private static final String GREEN = "\033[32m";
    private static final String CYAN = "\033[36m";

    public static void main (String [] args) throws IOException {
        Scanner scanner = new Scanner(new File(args[0]));
        scanner.useDelimiter("\\A");
        System.out.println(new XmlInColorsConverter().convert(scanner.next()));
    }

    String convert(String text) {
        return colorize(text, MARKUP.matcher(text));
    }

    private static String colorize(String input, Matcher matcher) {
        int lastEnd = 0;
        int level = 0;
        StringBuilder result = new StringBuilder();
        while (matcher.find()) {
            String oneMarkup = matcher.group();
            Matcher attrMatcher = ATTR.matcher(oneMarkup);
            String afterLastMatch = input.substring(lastEnd, matcher.start(2) == -1 ? 0 : matcher.start(2));
            level -= "/".equals(matcher.group(3)) ? 1 : 0;
            if (afterLastMatch.matches("\\s*")) {
                result.append("\n").append(IntStream.range(0, level).boxed().map(i -> "    ").collect(Collectors.joining()));
            } else {
                result.append(afterLastMatch);
            }
            level += matcher.group(3) == null ? 1 : 0;
            result.append(YELLOW).append("<").append((matcher.group(3) != null ? matcher.group(3) : "")).append((matcher.group(4) != null ? BLUE + matcher.group(4) + YELLOW + ":" : YELLOW)).append(matcher.group(5)).append(NORMAL);
            while (attrMatcher.find()) {
                result.append(" ").append((attrMatcher.group(2) != null ? BLUE + attrMatcher.group(2) + PINK + ":" : PINK)).append(attrMatcher.group(3)).append(GREEN).append("=").append(CYAN).append(attrMatcher.group(5));
            }
            level -= "/".equals(matcher.group(12)) ? 1 : 0;
            result.append(YELLOW).append((matcher.group(12) != null ? matcher.group(12) : "")).append(">").append(NORMAL);
            lastEnd = input.charAt(matcher.end()) == '\n' ? matcher.end() + 1 : matcher.end();
        }
        return result.toString();
    }
}