1 /* 2 * Licensed to the Apache Software Foundation (ASF) under one or more 3 * contributor license agreements. See the NOTICE file distributed with 4 * this work for additional information regarding copyright ownership. 5 * The ASF licenses this file to You under the Apache License, Version 2.0 6 * (the "License"); you may not use this file except in compliance with 7 * the License. You may obtain a copy of the License at 8 * 9 * http://www.apache.org/licenses/LICENSE-2.0 10 * 11 * Unless required by applicable law or agreed to in writing, software 12 * distributed under the License is distributed on an "AS IS" BASIS, 13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 14 * See the License for the specific language governing permissions and 15 * limitations under the License. 16 */ 17 18 package org.apache.log4j.spi; 19 20 import org.apache.log4j.Level; 21 import org.apache.log4j.Logger; 22 import org.apache.log4j.helpers.LogLog; 23 24 25 // Contibutors: Mathias Bogaert 26 27 /** 28 RootLogger sits at the top of the logger hierachy. It is a 29 regular logger except that it provides several guarantees. 30 31 <p>First, it cannot be assigned a <code>null</code> 32 level. Second, since root logger cannot have a parent, the 33 {@link #getChainedLevel} method always returns the value of the 34 level field without walking the hierarchy. 35 36 @author Ceki Gülcü 37 38 */ 39 public final class RootLogger extends Logger { 40 /** 41 The root logger names itself as "root". However, the root 42 logger cannot be retrieved by name. 43 */ 44 public RootLogger(Level level) { 45 super("root"); 46 setLevel(level); 47 } 48 49 /** 50 Return the assigned level value without walking the logger 51 hierarchy. 52 */ 53 public final Level getChainedLevel() { 54 return level; 55 } 56 57 /** 58 Setting a null value to the level of the root logger may have catastrophic 59 results. We prevent this here. 60 61 @since 0.8.3 */ 62 public final void setLevel(Level level) { 63 if (level == null) { 64 LogLog.error( 65 "You have tried to set a null level to root.", new Throwable()); 66 } else { 67 this.level = level; 68 } 69 } 70 71 }