Here is an example of a class using DatePatternToRegexUtil in Logback:

import ch.qos.logback.core.rolling.helper.DatePatternToRegexUtil;

public class MyClass {

    public void doSomething(String datePattern) {
        String regex = DatePatternToRegexUtil.toRegex(datePattern);
        // use regex
    }
}

This class is an example of using DatePatternToRegexUtil in Logback. DatePatternToRegexUtil is a utility class that provides a method toRegex(String datePattern) which is used to convert a date pattern to a regular expression.

In this example, MyClass has a doSomething method that takes in a date pattern and creates a regular expression by calling DatePatternToRegexUtil.toRegex(datePattern). The resulting regular expression can be used to match filenames that conform to the given date pattern.

It is important to note that DatePatternToRegexUtil is a utility class that provides a way to convert a date pattern to a regular expression. The date pattern is a string that describes the format of the date and time. The regular expression can be used to match filenames that conform to the given date pattern and is commonly used in the rollover mechanism of rolling file appenders.