View Javadoc

1   /*
2    * Copyright 2001-2004 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  
22  import java.io.IOException;
23  import java.io.ObjectInputStream;
24  import java.io.ObjectOutputStream;
25  import java.io.ObjectStreamException;
26  import java.io.Serializable;
27  
28  /**
29     Defines the minimum set of levels recognized by the system, that is
30     <code>OFF</code>, <code>FATAL</code>, <code>ERROR</code>,
31     <code>WARN</code>, <code>INFO</code>, <code>DEBUG</code> and
32     <code>ALL</code>.
33  
34     <p>The <code>Level</code> class may be subclassed to define a larger
35     level set.
36  
37     @author Ceki G&uuml;lc&uuml;
38  
39   */
40  public class Level extends Priority implements Serializable {
41  
42      /**
43       * TRACE level integer value.
44       * @since 1.2.12
45       */
46      public static final int TRACE_INT = 5000;
47  
48      // match jboss' xlevel
49      public static final int X_TRACE_INT = DEBUG_INT - 100;
50  
51      /**
52         The <code>OFF</code> has the highest possible rank and is
53         intended to turn off logging.  */
54      final static public Level OFF = new Level(OFF_INT, "OFF", 0);
55  
56      /**
57         The <code>FATAL</code> level designates very severe error
58         events that will presumably lead the application to abort.
59       */
60      final static public Level FATAL = new Level(FATAL_INT, "FATAL", 0);
61  
62      /**
63         The <code>ERROR</code> level designates error events that
64         might still allow the application to continue running.  */
65      final static public Level ERROR = new Level(ERROR_INT, "ERROR", 3);
66  
67      /**
68         The <code>WARN</code> level designates potentially harmful situations.
69      */
70      final static public Level WARN = new Level(WARN_INT, "WARN", 4);
71  
72      /**
73         The <code>INFO</code> level designates informational messages
74         that highlight the progress of the application at coarse-grained
75         level.  */
76      final static public Level INFO = new Level(INFO_INT, "INFO", 6);
77  
78      /**
79         The <code>DEBUG</code> Level designates fine-grained
80         informational events that are most useful to debug an
81         application.  */
82      final static public Level DEBUG = new Level(DEBUG_INT, "DEBUG", 7);
83  
84      /**
85        * The <code>TRACE</code> Level designates finer-grained
86        * informational events than the <code>DEBUG</code level.
87       *  @since 1.2.12
88        */
89      public static final Level TRACE = new Level(TRACE_INT, "TRACE", 7);
90  
91      /**
92         The <code>ALL</code> has the lowest possible rank and is intended to
93         turn on all logging.  */
94      final static public Level ALL = new Level(ALL_INT, "ALL", 7);
95  
96      /**
97       * Serialization version id.
98       */
99      static final long serialVersionUID = 3491141966387921974L;
100 
101     /**
102        Instantiate a Level object.
103      */
104     protected Level(int level, String levelStr, int syslogEquivalent) {
105         super(level, levelStr, syslogEquivalent);
106     }
107 
108     /**
109        Convert the string passed as argument to a level. If the
110        conversion fails, then this method returns {@link #DEBUG}. 
111     */
112     public static Level toLevel(String sArg) {
113         return (Level) toLevel(sArg, Level.DEBUG);
114     }
115 
116     /**
117       Convert an integer passed as argument to a level. If the
118       conversion fails, then this method returns {@link #DEBUG}.
119 
120     */
121     public static Level toLevel(int val) {
122         return (Level) toLevel(val, Level.DEBUG);
123     }
124 
125     /**
126       Convert an integer passed as argument to a level. If the
127       conversion fails, then this method returns the specified default.
128     */
129     public static Level toLevel(int val, Level defaultLevel) {
130         switch (val) {
131         case ALL_INT:
132             return ALL;
133         case DEBUG_INT:
134             return Level.DEBUG;
135         case INFO_INT:
136             return Level.INFO;
137         case WARN_INT:
138             return Level.WARN;
139         case ERROR_INT:
140             return Level.ERROR;
141         case FATAL_INT:
142             return Level.FATAL;
143         case OFF_INT:
144             return OFF;
145         case TRACE_INT:
146             return Level.TRACE;
147         default:
148             return defaultLevel;
149         }
150     }
151 
152     /**
153        Convert the string passed as argument to a level. If the
154        conversion fails, then this method returns the value of
155        <code>defaultLevel</code>.  
156     */
157     public static Level toLevel(String sArg, Level defaultLevel) {
158         if (sArg == null)
159             return defaultLevel;
160 
161         String s = sArg.toUpperCase();
162 
163         if (s.equals("ALL"))
164             return Level.ALL;
165         if (s.equals("DEBUG"))
166             return Level.DEBUG;
167         if (s.equals("INFO"))
168             return Level.INFO;
169         if (s.equals("WARN"))
170             return Level.WARN;
171         if (s.equals("ERROR"))
172             return Level.ERROR;
173         if (s.equals("FATAL"))
174             return Level.FATAL;
175         if (s.equals("OFF"))
176             return Level.OFF;
177         if (s.equals("TRACE"))
178             return Level.TRACE;
179         return defaultLevel;
180     }
181 
182     /**
183      * Custom deserialization of Level.
184      * @param s serialization stream.
185      * @throws IOException if IO exception.
186      * @throws ClassNotFoundException if class not found.
187      */
188     private void readObject(final ObjectInputStream s) throws IOException, ClassNotFoundException {
189         s.defaultReadObject();
190         level = s.readInt();
191         syslogEquivalent = s.readInt();
192         levelStr = s.readUTF();
193         if (levelStr == null) {
194             levelStr = "";
195         }
196     }
197 
198     /**
199      * Serialize level.
200      * @param s serialization stream.
201      * @throws IOException if exception during serialization.
202      */
203     private void writeObject(final ObjectOutputStream s) throws IOException {
204         s.defaultWriteObject();
205         s.writeInt(level);
206         s.writeInt(syslogEquivalent);
207         s.writeUTF(levelStr);
208     }
209 
210     /**
211      * Resolved deserialized level to one of the stock instances.
212      * May be overriden in classes derived from Level.
213      * @return resolved object.
214      * @throws ObjectStreamException if exception during resolution.
215      */
216     private Object readResolve() throws ObjectStreamException {
217         //
218         // if the deserizalized object is exactly an instance of Level
219         //
220         if (getClass() == Level.class) {
221             return toLevel(level);
222         }
223         //
224         // extension of Level can't substitute stock item
225         //
226         return this;
227     }
228 }