Added Regex.usingRe2j()

Author: jhy

CHANGES.md

@@ -11,7 +11,7 @@
     <version>1.8</version>
   </dependency>
  ```
-  (If you already have that dependency in your classpath, but you want to keep using the Java regex engine, you can disable re2j via `System.setProperty("jsoup.useRe2j", "false")`.) [#2407](https://github.com/jhy/jsoup/pull/2407)
+  (If you already have that dependency in your classpath, but you want to keep using the Java regex engine, you can disable re2j via `System.setProperty("jsoup.useRe2j", "false")`.) You can confirm that the re2j engine has been enabled correctly by calling `Regex.usingRe2j()`. [#2407](https://github.com/jhy/jsoup/pull/2407)
 
 * Added an instance method `Parser#unescape(String, boolean)` that unescapes HTML entities using the parser's configuration (e.g. to support error tracking), complementing the existing static utility `Parser.unescapeEntities(String, boolean)`. [#2396](https://github.com/jhy/jsoup/pull/2396)
 * Build: added CI coverage for JDK 25 [#2403](https://github.com/jhy/jsoup/pull/2403)

src/main/java/org/jsoup/helper/Regex.java

@@ -33,7 +33,7 @@ public class Regex {
      @throws ValidationException if the regex is invalid
      */
     public static Regex compile(String regex) {
-        if (hasRe2j && wantsRe2j()) {
+        if (usingRe2j()) {
             return Re2jRegex.compile(regex);
         }
 
@@ -49,6 +49,14 @@ public static Regex fromPattern(Pattern pattern) {
         return new Regex(pattern);
     }
 
+    /**
+     Checks if re2j is available (on classpath) and enabled (via system property).
+     @return true if re2j is available and enabled
+     */
+    public static boolean usingRe2j() {
+        return hasRe2j && wantsRe2j();
+    }
+
     static boolean wantsRe2j() {
         return Boolean.parseBoolean(System.getProperty(SharedConstants.UseRe2j, "true"));
     }

src/test/java/org/jsoup/helper/RegexTest.java

@@ -28,6 +28,7 @@ void tearDown() {
     @ValueSource(booleans = {false, true})
     void testRegexDelegates(boolean useRe2j) {
         Regex.wantsRe2j(useRe2j);
+        assertEquals(Regex.usingRe2j(), useRe2j);
         String pattern = "(\\d+)";
         String input = "12345";