1   /*
2    * Copyright 1999-2005 The Apache Software Foundation.
3    * 
4    * Licensed under the Apache License, Version 2.0 (the "License");
5    * you may not use this file except in compliance with the License.
6    * You may obtain a copy of the License at
7    * 
8    *      http://www.apache.org/licenses/LICENSE-2.0
9    * 
10   * Unless required by applicable law or agreed to in writing, software
11   * distributed under the License is distributed on an "AS IS" BASIS,
12   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13   * See the License for the specific language governing permissions and
14   * limitations under the License.
15   */
16  
17  // Contributors:  Kitching Simon <Simon.Kitching@orange.ch>
18  //                Nicholas Wolff
19  
20  package org.apache.log4j;
21  import java.io.IOException;
22  import java.io.ObjectInputStream;
23  import java.io.ObjectOutputStream;
24  import java.io.ObjectStreamException;
25  import java.io.Serializable;
26  
27  /**
28     Defines the minimum set of levels recognized by the system, that is
29     <code>OFF</code>, <code>FATAL</code>, <code>ERROR</code>,
30     <code>WARN</code>, <code>INFO</code>, <code>DEBUG</code> and
31     <code>ALL</code>.
32  
33     <p>The <code>Level</code> class may be subclassed to define a larger
34     level set.
35  
36     @author Ceki G&uuml;lc&uuml;
37  
38   */
39  public class Level extends Priority implements Serializable {
40  
41     /**
42      * TRACE level integer value.
43      * @since 1.2.12
44      */
45    public static final int TRACE_INT = 5000;
46  
47    /**
48       The <code>OFF</code> has the highest possible rank and is
49       intended to turn off logging.  */
50    final static public Level OFF = new Level(OFF_INT, "OFF", 0);
51  
52    /**
53       The <code>FATAL</code> level designates very severe error
54       events that will presumably lead the application to abort.
55     */
56    final static public Level FATAL = new Level(FATAL_INT, "FATAL", 0);
57  
58    /**
59       The <code>ERROR</code> level designates error events that
60       might still allow the application to continue running.  */
61    final static public Level ERROR = new Level(ERROR_INT, "ERROR", 3);
62  
63    /**
64       The <code>WARN</code> level designates potentially harmful situations.
65    */
66    final static public Level WARN  = new Level(WARN_INT, "WARN",  4);
67  
68    /**
69       The <code>INFO</code> level designates informational messages
70       that highlight the progress of the application at coarse-grained
71       level.  */
72    final static public Level INFO  = new Level(INFO_INT, "INFO",  6);
73  
74    /**
75       The <code>DEBUG</code> Level designates fine-grained
76       informational events that are most useful to debug an
77       application.  */
78    final static public Level DEBUG = new Level(DEBUG_INT, "DEBUG", 7);
79  
80    /**
81      * The <code>TRACE</code> Level designates finer-grained
82      * informational events than the <code>DEBUG</code level.
83     *  @since 1.2.12
84      */
85    public static final Level TRACE = new Level(TRACE_INT, "TRACE", 7);
86  
87  
88    /**
89       The <code>ALL</code> has the lowest possible rank and is intended to
90       turn on all logging.  */
91    final static public Level ALL = new Level(ALL_INT, "ALL", 7);
92  
93    /**
94     * Serialization version id.
95     */
96    static final long serialVersionUID = 3491141966387921974L;
97  
98    /**
99       Instantiate a Level object.
100    */
101   protected
102   Level(int level, String levelStr, int syslogEquivalent) {
103     super(level, levelStr, syslogEquivalent);
104   }
105 
106 
107   /**
108      Convert the string passed as argument to a level. If the
109      conversion fails, then this method returns {@link #DEBUG}. 
110   */
111   public
112   static
113   Level toLevel(String sArg) {
114     return (Level) toLevel(sArg, Level.DEBUG);
115   }
116 
117   /**
118     Convert an integer passed as argument to a level. If the
119     conversion fails, then this method returns {@link #DEBUG}.
120 
121   */
122   public
123   static
124   Level toLevel(int val) {
125     return (Level) toLevel(val, Level.DEBUG);
126   }
127 
128   /**
129     Convert an integer passed as argument to a level. If the
130     conversion fails, then this method returns the specified default.
131   */
132   public
133   static
134   Level toLevel(int val, Level defaultLevel) {
135     switch(val) {
136     case ALL_INT: return ALL;
137     case DEBUG_INT: return Level.DEBUG;
138     case INFO_INT: return Level.INFO;
139     case WARN_INT: return Level.WARN;
140     case ERROR_INT: return Level.ERROR;
141     case FATAL_INT: return Level.FATAL;
142     case OFF_INT: return OFF;
143     case TRACE_INT: return Level.TRACE;
144     default: return defaultLevel;
145     }
146   }
147 
148   /**
149      Convert the string passed as argument to a level. If the
150      conversion fails, then this method returns the value of
151      <code>defaultLevel</code>.  
152   */
153   public
154   static
155   Level toLevel(String sArg, Level defaultLevel) {                  
156     if(sArg == null)
157        return defaultLevel;
158     
159     String s = sArg.toUpperCase();
160 
161     if(s.equals("ALL")) return Level.ALL; 
162     if(s.equals("DEBUG")) return Level.DEBUG; 
163     if(s.equals("INFO"))  return Level.INFO;
164     if(s.equals("WARN"))  return Level.WARN;  
165     if(s.equals("ERROR")) return Level.ERROR;
166     if(s.equals("FATAL")) return Level.FATAL;
167     if(s.equals("OFF")) return Level.OFF;
168     if(s.equals("TRACE")) return Level.TRACE;
169     return defaultLevel;
170   }
171 
172     /**
173      * Custom deserialization of Level.
174      * @param s serialization stream.
175      * @throws IOException if IO exception.
176      * @throws ClassNotFoundException if class not found.
177      */
178     private void readObject(final ObjectInputStream s) throws IOException, ClassNotFoundException {
179       s.defaultReadObject();
180       level = s.readInt();
181       syslogEquivalent = s.readInt();
182       levelStr = s.readUTF();
183       if (levelStr == null) {
184           levelStr = "";
185       }
186     }
187 
188     /**
189      * Serialize level.
190      * @param s serialization stream.
191      * @throws IOException if exception during serialization.
192      */
193     private void writeObject(final ObjectOutputStream s) throws IOException {
194         s.defaultWriteObject();
195         s.writeInt(level);
196         s.writeInt(syslogEquivalent);
197         s.writeUTF(levelStr);
198     }
199 
200     /**
201      * Resolved deserialized level to one of the stock instances.
202      * May be overriden in classes derived from Level.
203      * @return resolved object.
204      * @throws ObjectStreamException if exception during resolution.
205      */
206     private Object readResolve() throws ObjectStreamException {
207         //
208         //  if the deserizalized object is exactly an instance of Level
209         //
210         if (getClass() == Level.class) {
211             return toLevel(level);
212         }
213         //
214         //   extension of Level can't substitute stock item
215         //
216         return this;
217     }
218 }