added LevelUtil

Signed-off-by: Ceki Gulcu <ceki@qos.ch>

logback-classic/src/main/java/ch/qos/logback/classic/util/LevelUtil.java

@@ -1,2 +1,51 @@
-package ch.qos.logback.classic.util;public class LevelUtil {
+/*
+ * Logback: the reliable, generic, fast and flexible logging framework.
+ * Copyright (C) 1999-2024, QOS.ch. All rights reserved.
+ *
+ * This program and the accompanying materials are dual-licensed under
+ * either the terms of the Eclipse Public License v1.0 as published by
+ * the Eclipse Foundation
+ *
+ *   or (per the licensee's choosing)
+ *
+ * under the terms of the GNU Lesser General Public License version 2.1
+ * as published by the Free Software Foundation.
+ */
+
+package ch.qos.logback.classic.util;
+
+import ch.qos.logback.classic.Level;
+import ch.qos.logback.core.joran.JoranConstants;
+import ch.qos.logback.core.util.OptionHelper;
+
+import static ch.qos.logback.core.joran.JoranConstants.NULL;
+
+/**
+ *
+ * Utility methods for transforming string values to Level.
+ *
+ * @since 1.5.1
+ */
+public class LevelUtil {
+
+
+    public static boolean isInheritedLevelString(String levelStr) {
+        if (JoranConstants.INHERITED.equalsIgnoreCase(levelStr) || NULL.equalsIgnoreCase(levelStr)) {
+            return true;
+        } else
+            return false;
+    }
+
+    public static Level levelStringToLevel(String levelStr) {
+        if (!OptionHelper.isNullOrEmptyOrAllSpaces(levelStr)) {
+            if (isInheritedLevelString(levelStr)) {
+                return null;
+            } else {
+                Level level = Level.toLevel(levelStr);
+                return level;
+            }
+        }
+        return null;
+    }
+
 }