001/*
002 * Copyright 2001-2004 The Apache Software Foundation.
003 *
004 * Licensed under the Apache License, Version 2.0 (the "License");
005 * you may not use this file except in compliance with the License.
006 * You may obtain a copy of the License at
007 *
008 *      http://www.apache.org/licenses/LICENSE-2.0
009 *
010 * Unless required by applicable law or agreed to in writing, software
011 * distributed under the License is distributed on an "AS IS" BASIS,
012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013 * See the License for the specific language governing permissions and
014 * limitations under the License.
015 */
016
017// Contributors:  Kitching Simon <Simon.Kitching@orange.ch>
018//                Nicholas Wolff
019
020package org.apache.log4j;
021
022import java.io.IOException;
023import java.io.ObjectInputStream;
024import java.io.ObjectOutputStream;
025import java.io.ObjectStreamException;
026import java.io.Serializable;
027
028/**
029   Defines the minimum set of levels recognized by the system, that is
030   <code>OFF</code>, <code>FATAL</code>, <code>ERROR</code>,
031   <code>WARN</code>, <code>INFO</code>, <code>DEBUG</code> and
032   <code>ALL</code>.
033
034   <p>The <code>Level</code> class may be subclassed to define a larger
035   level set.
036
037   @author Ceki G&uuml;lc&uuml;
038
039 */
040public class Level extends Priority implements Serializable {
041
042    /**
043     * TRACE level integer value.
044     * @since 1.2.12
045     */
046    public static final int TRACE_INT = 5000;
047
048    // match jboss' xlevel
049    public static final int X_TRACE_INT = DEBUG_INT - 100;
050
051    /**
052       The <code>OFF</code> has the highest possible rank and is
053       intended to turn off logging.  */
054    final static public Level OFF = new Level(OFF_INT, "OFF", 0);
055
056    /**
057       The <code>FATAL</code> level designates very severe error
058       events that will presumably lead the application to abort.
059     */
060    final static public Level FATAL = new Level(FATAL_INT, "FATAL", 0);
061
062    /**
063       The <code>ERROR</code> level designates error events that
064       might still allow the application to continue running.  */
065    final static public Level ERROR = new Level(ERROR_INT, "ERROR", 3);
066
067    /**
068       The <code>WARN</code> level designates potentially harmful situations.
069    */
070    final static public Level WARN = new Level(WARN_INT, "WARN", 4);
071
072    /**
073       The <code>INFO</code> level designates informational messages
074       that highlight the progress of the application at coarse-grained
075       level.  */
076    final static public Level INFO = new Level(INFO_INT, "INFO", 6);
077
078    /**
079       The <code>DEBUG</code> Level designates fine-grained
080       informational events that are most useful to debug an
081       application.  */
082    final static public Level DEBUG = new Level(DEBUG_INT, "DEBUG", 7);
083
084    /**
085      * The <code>TRACE</code> Level designates finer-grained
086      * informational events than the <code>DEBUG</code level.
087     *  @since 1.2.12
088      */
089    public static final Level TRACE = new Level(TRACE_INT, "TRACE", 7);
090
091    /**
092       The <code>ALL</code> has the lowest possible rank and is intended to
093       turn on all logging.  */
094    final static public Level ALL = new Level(ALL_INT, "ALL", 7);
095
096    /**
097     * Serialization version id.
098     */
099    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 overridden 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 deserialized 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}