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}