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Re: how to detect two or more roots in xml

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On 2/23/2021 12:22 PM, mike wrote:
> I will have files like:

> I will need to parse to xml:

> However it is not valid xml since it is two roots. How can I detect
> that I have two roots. Currently I am only seeing this when parse
> fails ( see below) And message is too general to know there are
> multiple ( in this case 2) roots. If I can detect multi roots I can
> split string and parse each and add them together later ( I think).
Parsing and catching is probably the most safe approach.

If you want a string hack then regex may be the easiest approach.

For inspiration:

import java.util.regex.Matcher;
import java.util.regex.Pattern;

public class XmlSniffer {
     private static Pattern either = 
Pattern.compile("(\\<[\\w-]+.*?\\>)|(\\</[\\w-]+\\>)");
     private static Pattern start = Pattern.compile("\\<[\\w-]+.*?\\>");
     private static Pattern end = Pattern.compile("\\</[\\w-]+\\>");
     private static Pattern both = Pattern.compile("\\<[\\w-]+.*?/\\>");
     public static boolean check(String xmlstr) {
         Matcher e = either.matcher(xmlstr);
         int depth = 0;
         boolean first = true;
         while(e.find()) {
             String piece = e.group();
             if(start.matcher(piece).matches()) {
                 if(depth == 0) {
                     if(first) {
                         first = false;
                     } else {
                         return false;
                     }
                 }
                 if(!both.matcher(piece).matches()) {
                     depth++;
                 }
             } else if(end.matcher(piece).matches()) {
                 depth--;
             }
         }
         return true;
     }
     private static void test(String xmlstr) {
         System.out.println(xmlstr);
         System.out.println(check(xmlstr));
     }
     public static void main(String[] args) {
         test("<a/>");
         test("<a>xxxx</a>");
         test("<a>\r\n    <b>xxxx</b>\r\n</a>");
         test("<a>\r\n    <b/>\r\n</a>");
         test("<a>xxxx</a>\r\n<c>yyyy</c>");
         test("<a>\r\n    <b>xxxx</b>\r\n</a>\r\n<c>yyyy</c>");
         test("<a>\r\n    <b/>\r\n</a>\r\n<c>yyyy</c>");
         test("<a>xxxx</a>\r\n<c/>");
         test("<a>\r\n    <b>xxxx</b>\r\n</a>\r\n<c/>");
         test("<a>\r\n    <b/>\r\n</a>\r\n<c/>");
         test("<a/>\r\n<c/>");
     }
}


Arne

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Thread

how to detect two or more roots in xml mike <mikaelpetterson@hotmail.com> - 2021-02-23 09:22 -0800
  Re: how to detect two or more roots in xml Arne Vajhøj <arne@vajhoej.dk> - 2021-02-23 21:27 -0500
    Re: how to detect two or more roots in xml mike <mikaelpetterson@hotmail.com> - 2021-02-24 00:33 -0800
  Re: how to detect two or more roots in xml Daniele Futtorovic <da.futt.news@laposte-dot-net.invalid> - 2021-02-25 15:29 +0100

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