1 /*
2 * Licensed to the Apache Software Foundation (ASF) under one or more
3 * contributor license agreements. See the NOTICE file distributed with
4 * this work for additional information regarding copyright ownership.
5 * The ASF licenses this file to You under the Apache License, Version 2.0
6 * (the "License"); you may not use this file except in compliance with
7 * the License. You may obtain a copy of the License at
8 *
9 * http://www.apache.org/licenses/LICENSE-2.0
10 *
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the License for the specific language governing permissions and
15 * limitations under the License.
16 */
17
18
19 package org.apache.commons.logging.impl;
20
21 import java.io.Serializable;
22 import org.apache.commons.logging.Log;
23 import org.apache.log4j.Logger;
24 import org.apache.log4j.Priority;
25 import org.apache.log4j.Level;
26
27 /**
28 * Implementation of {@link Log} that maps directly to a
29 * <strong>Logger</strong> for log4J version 1.2.
30 * <p>
31 * Initial configuration of the corresponding Logger instances should be done
32 * in the usual manner, as outlined in the Log4J documentation.
33 * <p>
34 * The reason this logger is distinct from the 1.3 logger is that in version 1.2
35 * of Log4J:
36 * <ul>
37 * <li>class Logger takes Priority parameters not Level parameters.
38 * <li>class Level extends Priority
39 * </ul>
40 * Log4J1.3 is expected to change Level so it no longer extends Priority, which is
41 * a non-binary-compatible change. The class generated by compiling this code against
42 * log4j 1.2 will therefore not run against log4j 1.3.
43 *
44 * @author <a href="mailto:sanders@apache.org">Scott Sanders</a>
45 * @author Rod Waldhoff
46 * @author Robert Burrell Donkin
47 * @version $Id: Log4JLogger.java 479747 2006-11-27 20:15:01Z dennisl $
48 */
49
50 public class Log4JLogger implements Log, Serializable {
51
52 // ------------------------------------------------------------- Attributes
53
54 /** The fully qualified name of the Log4JLogger class. */
55 private static final String FQCN = Log4JLogger.class.getName();
56
57 /** Log to this logger */
58 private transient Logger logger = null;
59
60 /** Logger name */
61 private String name = null;
62
63 private static Priority traceLevel;
64
65 // ------------------------------------------------------------
66 // Static Initializer.
67 //
68 // Note that this must come after the static variable declarations
69 // otherwise initialiser expressions associated with those variables
70 // will override any settings done here.
71 //
72 // Verify that log4j is available, and that it is version 1.2.
73 // If an ExceptionInInitializerError is generated, then LogFactoryImpl
74 // will treat that as meaning that the appropriate underlying logging
75 // library is just not present - if discovery is in progress then
76 // discovery will continue.
77 // ------------------------------------------------------------
78
79 static {
80 if (!Priority.class.isAssignableFrom(Level.class)) {
81 // nope, this is log4j 1.3, so force an ExceptionInInitializerError
82 throw new InstantiationError("Log4J 1.2 not available");
83 }
84
85 // Releases of log4j1.2 >= 1.2.12 have Priority.TRACE available, earlier
86 // versions do not. If TRACE is not available, then we have to map
87 // calls to Log.trace(...) onto the DEBUG level.
88
89 try {
90 traceLevel = (Priority) Level.class.getDeclaredField("TRACE").get(null);
91 } catch(Exception ex) {
92 // ok, trace not available
93 traceLevel = Priority.DEBUG;
94 }
95 }
96
97
98 // ------------------------------------------------------------ Constructor
99
100 public Log4JLogger() {
101 }
102
103
104 /**
105 * Base constructor.
106 */
107 public Log4JLogger(String name) {
108 this.name = name;
109 this.logger = getLogger();
110 }
111
112 /**
113 * For use with a log4j factory.
114 */
115 public Log4JLogger(Logger logger ) {
116 if (logger == null) {
117 throw new IllegalArgumentException(
118 "Warning - null logger in constructor; possible log4j misconfiguration.");
119 }
120 this.name = logger.getName();
121 this.logger=logger;
122 }
123
124
125 // ---------------------------------------------------------
126 // Implementation
127 //
128 // Note that in the methods below the Priority class is used to define
129 // levels even though the Level class is supported in 1.2. This is done
130 // so that at compile time the call definitely resolves to a call to
131 // a method that takes a Priority rather than one that takes a Level.
132 //
133 // The Category class (and hence its subclass Logger) in version 1.2 only
134 // has methods that take Priority objects. The Category class (and hence
135 // Logger class) in version 1.3 has methods that take both Priority and
136 // Level objects. This means that if we use Level here, and compile
137 // against log4j 1.3 then calls would be bound to the versions of
138 // methods taking Level objects and then would fail to run against
139 // version 1.2 of log4j.
140 // ---------------------------------------------------------
141
142
143 /**
144 * Logs a message with <code>org.apache.log4j.Priority.TRACE</code>.
145 * When using a log4j version that does not support the <code>TRACE</code>
146 * level, the message will be logged at the <code>DEBUG</code> level.
147 *
148 * @param message to log
149 * @see org.apache.commons.logging.Log#trace(Object)
150 */
151 public void trace(Object message) {
152 getLogger().log(FQCN, traceLevel, message, null );
153 }
154
155
156 /**
157 * Logs a message with <code>org.apache.log4j.Priority.TRACE</code>.
158 * When using a log4j version that does not support the <code>TRACE</code>
159 * level, the message will be logged at the <code>DEBUG</code> level.
160 *
161 * @param message to log
162 * @param t log this cause
163 * @see org.apache.commons.logging.Log#trace(Object, Throwable)
164 */
165 public void trace(Object message, Throwable t) {
166 getLogger().log(FQCN, traceLevel, message, t );
167 }
168
169
170 /**
171 * Logs a message with <code>org.apache.log4j.Priority.DEBUG</code>.
172 *
173 * @param message to log
174 * @see org.apache.commons.logging.Log#debug(Object)
175 */
176 public void debug(Object message) {
177 getLogger().log(FQCN, Priority.DEBUG, message, null );
178 }
179
180 /**
181 * Logs a message with <code>org.apache.log4j.Priority.DEBUG</code>.
182 *
183 * @param message to log
184 * @param t log this cause
185 * @see org.apache.commons.logging.Log#debug(Object, Throwable)
186 */
187 public void debug(Object message, Throwable t) {
188 getLogger().log(FQCN, Priority.DEBUG, message, t );
189 }
190
191
192 /**
193 * Logs a message with <code>org.apache.log4j.Priority.INFO</code>.
194 *
195 * @param message to log
196 * @see org.apache.commons.logging.Log#info(Object)
197 */
198 public void info(Object message) {
199 getLogger().log(FQCN, Priority.INFO, message, null );
200 }
201
202
203 /**
204 * Logs a message with <code>org.apache.log4j.Priority.INFO</code>.
205 *
206 * @param message to log
207 * @param t log this cause
208 * @see org.apache.commons.logging.Log#info(Object, Throwable)
209 */
210 public void info(Object message, Throwable t) {
211 getLogger().log(FQCN, Priority.INFO, message, t );
212 }
213
214
215 /**
216 * Logs a message with <code>org.apache.log4j.Priority.WARN</code>.
217 *
218 * @param message to log
219 * @see org.apache.commons.logging.Log#warn(Object)
220 */
221 public void warn(Object message) {
222 getLogger().log(FQCN, Priority.WARN, message, null );
223 }
224
225
226 /**
227 * Logs a message with <code>org.apache.log4j.Priority.WARN</code>.
228 *
229 * @param message to log
230 * @param t log this cause
231 * @see org.apache.commons.logging.Log#warn(Object, Throwable)
232 */
233 public void warn(Object message, Throwable t) {
234 getLogger().log(FQCN, Priority.WARN, message, t );
235 }
236
237
238 /**
239 * Logs a message with <code>org.apache.log4j.Priority.ERROR</code>.
240 *
241 * @param message to log
242 * @see org.apache.commons.logging.Log#error(Object)
243 */
244 public void error(Object message) {
245 getLogger().log(FQCN, Priority.ERROR, message, null );
246 }
247
248
249 /**
250 * Logs a message with <code>org.apache.log4j.Priority.ERROR</code>.
251 *
252 * @param message to log
253 * @param t log this cause
254 * @see org.apache.commons.logging.Log#error(Object, Throwable)
255 */
256 public void error(Object message, Throwable t) {
257 getLogger().log(FQCN, Priority.ERROR, message, t );
258 }
259
260
261 /**
262 * Logs a message with <code>org.apache.log4j.Priority.FATAL</code>.
263 *
264 * @param message to log
265 * @see org.apache.commons.logging.Log#fatal(Object)
266 */
267 public void fatal(Object message) {
268 getLogger().log(FQCN, Priority.FATAL, message, null );
269 }
270
271
272 /**
273 * Logs a message with <code>org.apache.log4j.Priority.FATAL</code>.
274 *
275 * @param message to log
276 * @param t log this cause
277 * @see org.apache.commons.logging.Log#fatal(Object, Throwable)
278 */
279 public void fatal(Object message, Throwable t) {
280 getLogger().log(FQCN, Priority.FATAL, message, t );
281 }
282
283
284 /**
285 * Return the native Logger instance we are using.
286 */
287 public Logger getLogger() {
288 if (logger == null) {
289 logger = Logger.getLogger(name);
290 }
291 return (this.logger);
292 }
293
294
295 /**
296 * Check whether the Log4j Logger used is enabled for <code>DEBUG</code> priority.
297 */
298 public boolean isDebugEnabled() {
299 return getLogger().isDebugEnabled();
300 }
301
302
303 /**
304 * Check whether the Log4j Logger used is enabled for <code>ERROR</code> priority.
305 */
306 public boolean isErrorEnabled() {
307 return getLogger().isEnabledFor(Priority.ERROR);
308 }
309
310
311 /**
312 * Check whether the Log4j Logger used is enabled for <code>FATAL</code> priority.
313 */
314 public boolean isFatalEnabled() {
315 return getLogger().isEnabledFor(Priority.FATAL);
316 }
317
318
319 /**
320 * Check whether the Log4j Logger used is enabled for <code>INFO</code> priority.
321 */
322 public boolean isInfoEnabled() {
323 return getLogger().isInfoEnabled();
324 }
325
326
327 /**
328 * Check whether the Log4j Logger used is enabled for <code>TRACE</code> priority.
329 * When using a log4j version that does not support the TRACE level, this call
330 * will report whether <code>DEBUG</code> is enabled or not.
331 */
332 public boolean isTraceEnabled() {
333 return getLogger().isEnabledFor(traceLevel);
334 }
335
336 /**
337 * Check whether the Log4j Logger used is enabled for <code>WARN</code> priority.
338 */
339 public boolean isWarnEnabled() {
340 return getLogger().isEnabledFor(Priority.WARN);
341 }
342 }