Check if a String matches a particular MessageFormat in Java?

Question

I have a MessageFormat like so;

final MessageFormat messageFormat = new MessageFormat("This is token one {0}, and token two {1}");

I'm just wondering if I have some Strings like;

String shouldMatch = "This is token one bla, and token two bla";
String wontMatch = "This wont match the above MessageFormat";

How do I check if the above Strings were created using messageFormat? I.e. that they match the messageFormat?

Many thanks!

Answer 1

You can do that using Regular Expressions and Pattern and Matcher classes. A simple example:

Pattern pat = Pattern.compile("^This is token one \\w+, and token two \\w+$");
Matcher mat = pat.matcher(shouldMatch);
if(mat.matches()) {
   ...
}

Explanation of regex:

^ = beginning of line
\w = a word character. I put \\w because it is inside a Java String so \\ is actually a \
+ = the previous character can occur one ore more times, so at least one character should be there
$ = end of line

If you want to capture the tokens, use braces like this:

Pattern pat = Pattern.compile("^This is token one (\\w+), and token two (\\w+)$");

You can retrieve the groups using mat.group(1) and mat.group(2).

Answer 2

Apart from the Reg Ex answer it can be done also with this code I have just developed:

public class Points {
    private int start;

    public int getStart() {
        return start;
    }

    public void setStart(int start) {
        this.start = start;
    }
    private int end;

    public int getEnd() {
        return end;
    }

    public void setEnd(int end) {
        this.end = end;
    }
}

public class Split {
    public static void main(String[] args) {
        final MessageFormat messageFormat = new MessageFormat("This is token one {0}, and token two {1}");

        ArrayList<String> list = new ArrayList<String>();
        list.add("This is token one bla, and token two bla");
        list.add("This wont match the above MessageFormat");
        list.add("This wont match the above MessageFormat");
        list.add("This wont match the above MessageFormat");
        list.add("This is token one bla, and token two bla");
        list.add("This wont match the above MessageFormat");

        Format[] format = messageFormat.getFormats();
        int del = format.length;

        ArrayList<String> delimeters = new ArrayList<String>();
        for (int i = 0; i < del; i++) {
            delimeters.add("{" + i + "}");
        }
        //System.out.println(messageFormat.toPattern());
        ArrayList<Points> points = new ArrayList<Points>();
        int counter = 0;
        for (String x : delimeters) {
            Points tmp = new Points();
            tmp.setStart(counter);
            int ending = messageFormat.toPattern().indexOf(x);
            counter = ending + x.length();
            tmp.setEnd(ending);
            points.add(tmp);
        }

        for (String x : list) {
            boolean match = true;
            for (Points y : points) {
                if (match) {
                    if (x.substring(y.getStart(), y.getEnd()).equals(messageFormat.toPattern().substring(y.getStart(), y.getEnd()))) {
                    } else {
                        match = false;
                    }
                }
            }
            if (match) {
                System.out.println("Match!!!");
            } else {
                System.out.println("Not Match!!");
            }
        }

    }
}

Running this will print you the output

Match!!!

Not Match!!

Not Match!!

Not Match!!

Match!!!

Not Match!!

Hope you like it!