--- /dev/null
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.log4j.spi;
+
+import org.apache.log4j.Level;
+import org.apache.log4j.Logger;
+import org.apache.log4j.helpers.LogLog;
+
+
+// Contibutors: Mathias Bogaert
+
+/**
+ RootLogger sits at the top of the logger hierachy. It is a
+ regular logger except that it provides several guarantees.
+
+ <p>First, it cannot be assigned a <code>null</code>
+ level. Second, since root logger cannot have a parent, the
+ {@link #getChainedLevel} method always returns the value of the
+ level field without walking the hierarchy.
+
+ @author Ceki Gülcü
+
+ */
+public final class RootLogger extends Logger {
+ /**
+ The root logger names itself as "root". However, the root
+ logger cannot be retrieved by name.
+ */
+ public RootLogger(Level level) {
+ super("root");
+ setLevel(level);
+ }
+
+ /**
+ Return the assigned level value without walking the logger
+ hierarchy.
+ */
+ public final Level getChainedLevel() {
+ return level;
+ }
+
+ /**
+ Setting a null value to the level of the root logger may have catastrophic
+ results. We prevent this here.
+
+ @since 0.8.3 */
+ public final void setLevel(Level level) {
+ if (level == null) {
+ LogLog.error(
+ "You have tried to set a null level to root.", new Throwable());
+ } else {
+ this.level = level;
+ }
+ }
+
+}