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>, <code>WARN</code>,
031 * <code>INFO</code>, <code>DEBUG</code> and <code>ALL</code>.
032 * 
033 * <p>
034 * The <code>Level</code> class may be subclassed to define a larger level set.
035 * 
036 * @author Ceki G&uuml;lc&uuml;
037 * 
038 */
039public class Level extends Priority implements Serializable {
040
041    /**
042     * TRACE level integer value.
043     * 
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 intended to turn
053     * off logging.
054     */
055    final static public Level OFF = new Level(OFF_INT, "OFF", 0);
056
057    /**
058     * The <code>FATAL</code> level designates very severe error events that will
059     * presumably lead the application to abort.
060     */
061    final static public Level FATAL = new Level(FATAL_INT, "FATAL", 0);
062
063    /**
064     * The <code>ERROR</code> level designates error events that might still allow
065     * the application to continue running.
066     */
067    final static public Level ERROR = new Level(ERROR_INT, "ERROR", 3);
068
069    /**
070     * The <code>WARN</code> level designates potentially harmful situations.
071     */
072    final static public Level WARN = new Level(WARN_INT, "WARN", 4);
073
074    /**
075     * The <code>INFO</code> level designates informational messages that highlight
076     * the progress of the application at coarse-grained level.
077     */
078    final static public Level INFO = new Level(INFO_INT, "INFO", 6);
079
080    /**
081     * The <code>DEBUG</code> Level designates fine-grained informational events
082     * that are most useful to debug an application.
083     */
084    final static public Level DEBUG = new Level(DEBUG_INT, "DEBUG", 7);
085
086    /**
087     * The <code>TRACE</code> Level designates finer-grained informational events
088     * than the <code>DEBUG</code> level.
089     * 
090     * @since 1.2.12
091     */
092    public static final Level TRACE = new Level(TRACE_INT, "TRACE", 7);
093
094    /**
095     * The <code>ALL</code> has the lowest possible rank and is intended to turn on
096     * all logging.
097     */
098    final static public Level ALL = new Level(ALL_INT, "ALL", 7);
099
100    /**
101     * Serialization version id.
102     */
103    static final long serialVersionUID = 3491141966387921974L;
104
105    /**
106     * Instantiate a Level object.
107     * 
108     * @param level a level
109     * @param levelStr  a level string
110     * @param syslogEquivalent  the Syslog equivalent
111     */
112    protected Level(int level, String levelStr, int syslogEquivalent) {
113        super(level, levelStr, syslogEquivalent);
114    }
115
116    /**
117     * Convert the string passed as argument to a level. If the conversion fails,
118     * then this method returns {@link #DEBUG}.
119     * 
120     * @param sArg a string
121     * @return corresponding Level
122     * 
123     */
124    public static Level toLevel(String sArg) {
125        return (Level) toLevel(sArg, Level.DEBUG);
126    }
127
128    /**
129     * Convert an integer passed as argument to a level. If the conversion fails,
130     * then this method returns {@link #DEBUG}.
131     * 
132     * @param val an int
133     * @return a level
134     */
135    public static Level toLevel(int val) {
136        return (Level) toLevel(val, Level.DEBUG);
137    }
138
139    /**
140     * Convert an integer passed as argument to a level. If the conversion fails,
141     * then this method returns the specified default.
142     * 
143     * @param val a value 
144     * @param defaultLevel a defaultLevel
145     * @return corresponding Level
146     */
147    public static Level toLevel(int val, Level defaultLevel) {
148        switch (val) {
149        case ALL_INT:
150            return ALL;
151        case DEBUG_INT:
152            return Level.DEBUG;
153        case INFO_INT:
154            return Level.INFO;
155        case WARN_INT:
156            return Level.WARN;
157        case ERROR_INT:
158            return Level.ERROR;
159        case FATAL_INT:
160            return Level.FATAL;
161        case OFF_INT:
162            return OFF;
163        case TRACE_INT:
164            return Level.TRACE;
165        default:
166            return defaultLevel;
167        }
168    }
169
170    /**
171     * Convert the string passed as argument to a level. If the conversion fails,
172     * then this method returns the value of <code>defaultLevel</code>.
173     *
174     * @param sArg a string 
175     * @param defaultLevel a default level
176     * @return corresponding level
177     */
178    public static Level toLevel(String sArg, Level defaultLevel) {
179        if (sArg == null)
180            return defaultLevel;
181
182        String s = sArg.toUpperCase();
183
184        if (s.equals("ALL"))
185            return Level.ALL;
186        if (s.equals("DEBUG"))
187            return Level.DEBUG;
188        if (s.equals("INFO"))
189            return Level.INFO;
190        if (s.equals("WARN"))
191            return Level.WARN;
192        if (s.equals("ERROR"))
193            return Level.ERROR;
194        if (s.equals("FATAL"))
195            return Level.FATAL;
196        if (s.equals("OFF"))
197            return Level.OFF;
198        if (s.equals("TRACE"))
199            return Level.TRACE;
200        return defaultLevel;
201    }
202
203    /**
204     * Custom deserialization of Level.
205     * 
206     * @param s serialization stream.
207     * @throws IOException            if IO exception.
208     * @throws ClassNotFoundException if class not found.
209     */
210    private void readObject(final ObjectInputStream s) throws IOException, ClassNotFoundException {
211        s.defaultReadObject();
212        level = s.readInt();
213        syslogEquivalent = s.readInt();
214        levelStr = s.readUTF();
215        if (levelStr == null) {
216            levelStr = "";
217        }
218    }
219
220    /**
221     * Serialize level.
222     * 
223     * @param s serialization stream.
224     * @throws IOException if exception during serialization.
225     */
226    private void writeObject(final ObjectOutputStream s) throws IOException {
227        s.defaultWriteObject();
228        s.writeInt(level);
229        s.writeInt(syslogEquivalent);
230        s.writeUTF(levelStr);
231    }
232
233    /**
234     * Resolved deserialized level to one of the stock instances. May be overridden
235     * in classes derived from Level.
236     * 
237     * @return resolved object.
238     * @throws ObjectStreamException if exception during resolution.
239     */
240    private Object readResolve() throws ObjectStreamException {
241        //
242        // if the deserialized object is exactly an instance of Level
243        //
244        if (getClass() == Level.class) {
245            return toLevel(level);
246        }
247        //
248        // extension of Level can't substitute stock item
249        //
250        return this;
251    }
252}