001 /* ======================================================================== 002 * JCommon : a free general purpose class library for the Java(tm) platform 003 * ======================================================================== 004 * 005 * (C) Copyright 2000-2005, by Object Refinery Limited and Contributors. 006 * 007 * Project Info: http://www.jfree.org/jcommon/index.html 008 * 009 * This library is free software; you can redistribute it and/or modify it 010 * under the terms of the GNU Lesser General Public License as published by 011 * the Free Software Foundation; either version 2.1 of the License, or 012 * (at your option) any later version. 013 * 014 * This library is distributed in the hope that it will be useful, but 015 * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY 016 * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public 017 * License for more details. 018 * 019 * You should have received a copy of the GNU Lesser General Public 020 * License along with this library; if not, write to the Free Software 021 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, 022 * USA. 023 * 024 * [Java is a trademark or registered trademark of Sun Microsystems, Inc. 025 * in the United States and other countries.] 026 * 027 * -------- 028 * Log.java 029 * -------- 030 * (C)opyright 2002-2004, by Thomas Morgner and Contributors. 031 * 032 * Original Author: Thomas Morgner (taquera@sherito.org); 033 * Contributor(s): David Gilbert (for Object Refinery Limited); 034 * 035 * $Id: Log.java,v 1.4 2005/11/14 10:55:43 mungady Exp $ 036 * 037 * Changes 038 * ------- 039 * 29-Apr-2003 : Distilled from the JFreeReport project and moved into JCommon 040 * 11-Jun-2003 : Removing LogTarget did not work. 041 * 042 */ 043 044 package org.jfree.util; 045 046 import java.util.ArrayList; 047 import java.util.Arrays; 048 import java.util.HashMap; 049 050 /** 051 * A simple logging facility. Create a class implementing the {@link org.jfree.util.LogTarget} 052 * interface to use this feature. 053 * 054 * @author Thomas Morgner 055 */ 056 public class Log { 057 058 /** 059 * A simple message class. 060 */ 061 public static class SimpleMessage { 062 063 /** 064 * The message. 065 */ 066 private String message; 067 068 /** 069 * The parameters. 070 */ 071 private Object[] param; 072 073 /** 074 * Creates a new message. 075 * 076 * @param message the message text. 077 * @param param1 parameter 1. 078 */ 079 public SimpleMessage(final String message, final Object param1) { 080 this.message = message; 081 this.param = new Object[]{param1}; 082 } 083 084 /** 085 * Creates a new message. 086 * 087 * @param message the message text. 088 * @param param1 parameter 1. 089 * @param param2 parameter 2. 090 */ 091 public SimpleMessage(final String message, final Object param1, 092 final Object param2) { 093 this.message = message; 094 this.param = new Object[]{param1, param2}; 095 } 096 097 /** 098 * Creates a new message. 099 * 100 * @param message the message text. 101 * @param param1 parameter 1. 102 * @param param2 parameter 2. 103 * @param param3 parameter 3. 104 */ 105 public SimpleMessage(final String message, final Object param1, 106 final Object param2, final Object param3) { 107 this.message = message; 108 this.param = new Object[]{param1, param2, param3}; 109 } 110 111 /** 112 * Creates a new message. 113 * 114 * @param message the message text. 115 * @param param1 parameter 1. 116 * @param param2 parameter 2. 117 * @param param3 parameter 3. 118 * @param param4 parameter 4. 119 */ 120 public SimpleMessage(final String message, final Object param1, 121 final Object param2, final Object param3, 122 final Object param4) { 123 this.message = message; 124 this.param = new Object[]{param1, param2, param3, param4}; 125 } 126 127 /** 128 * Creates a new message. 129 * 130 * @param message the message text. 131 * @param param the parameters. 132 */ 133 public SimpleMessage(final String message, final Object[] param) { 134 this.message = message; 135 this.param = param; 136 } 137 138 /** 139 * Returns a string representation of the message (useful for debugging). 140 * 141 * @return the string. 142 */ 143 public String toString() { 144 final StringBuffer b = new StringBuffer(); 145 b.append(this.message); 146 if (this.param != null) { 147 for (int i = 0; i < this.param.length; i++) { 148 b.append(this.param[i]); 149 } 150 } 151 return b.toString(); 152 } 153 } 154 155 156 /** 157 * The logging threshold. 158 */ 159 private int debuglevel; 160 161 /** 162 * Storage for the log targets. 163 */ 164 private LogTarget[] logTargets; 165 166 /** The log contexts. */ 167 private HashMap logContexts; 168 169 /** 170 * the singleton instance of the Log system. 171 */ 172 private static Log singleton; 173 174 /** 175 * Creates a new Log instance. The Log is used to manage the log targets. 176 */ 177 protected Log() { 178 this.logContexts = new HashMap(); 179 this.logTargets = new LogTarget[0]; 180 this.debuglevel = 100; 181 } 182 183 /** 184 * Returns the singleton Log instance. A new instance is created if necessary. 185 * 186 * @return the singleton instance. 187 */ 188 public static synchronized Log getInstance() { 189 if (singleton == null) { 190 singleton = new Log(); 191 } 192 return singleton; 193 } 194 195 /** 196 * Redefines or clears the currently used log instance. 197 * 198 * @param log the new log instance or null, to return to the default implementation. 199 */ 200 protected static synchronized void defineLog(final Log log) { 201 singleton = log; 202 } 203 204 /** 205 * Returns the currently defined debug level. The higher the level, the more details 206 * are printed. 207 * 208 * @return the debug level. 209 */ 210 public int getDebuglevel() { 211 return this.debuglevel; 212 } 213 214 /** 215 * Defines the debug level for the log system. 216 * 217 * @param debuglevel the new debug level 218 * @see #getDebuglevel() 219 */ 220 protected void setDebuglevel(final int debuglevel) { 221 this.debuglevel = debuglevel; 222 } 223 224 /** 225 * Adds a log target to this facility. Log targets get informed, via the LogTarget interface, 226 * whenever a message is logged with this class. 227 * 228 * @param target the target. 229 */ 230 public synchronized void addTarget(final LogTarget target) { 231 if (target == null) { 232 throw new NullPointerException(); 233 } 234 final LogTarget[] data = new LogTarget[this.logTargets.length + 1]; 235 System.arraycopy(this.logTargets, 0, data, 0, this.logTargets.length); 236 data[this.logTargets.length] = target; 237 this.logTargets = data; 238 } 239 240 /** 241 * Removes a log target from this facility. 242 * 243 * @param target the target to remove. 244 */ 245 public synchronized void removeTarget(final LogTarget target) { 246 if (target == null) { 247 throw new NullPointerException(); 248 } 249 final ArrayList l = new ArrayList(); 250 l.addAll(Arrays.asList(this.logTargets)); 251 l.remove(target); 252 253 final LogTarget[] targets = new LogTarget[l.size()]; 254 this.logTargets = (LogTarget[]) l.toArray(targets); 255 } 256 257 /** 258 * Returns the registered logtargets. 259 * 260 * @return the logtargets. 261 */ 262 public LogTarget[] getTargets() { 263 final LogTarget[] targets = new LogTarget[this.logTargets.length]; 264 System.arraycopy(targets, 0, this.logTargets, 0, this.logTargets.length); 265 return targets; 266 } 267 268 /** 269 * Replaces all log targets by the given target. 270 * 271 * @param target the new and only logtarget. 272 */ 273 public synchronized void replaceTargets(final LogTarget target) { 274 if (target == null) { 275 throw new NullPointerException(); 276 } 277 this.logTargets = new LogTarget[]{target}; 278 } 279 280 /** 281 * A convenience method for logging a 'debug' message. 282 * 283 * @param message the message. 284 */ 285 public static void debug(final Object message) { 286 log(LogTarget.DEBUG, message); 287 } 288 289 /** 290 * A convenience method for logging a 'debug' message. 291 * 292 * @param message the message. 293 * @param e the exception. 294 */ 295 public static void debug(final Object message, final Exception e) { 296 log(LogTarget.DEBUG, message, e); 297 } 298 299 /** 300 * A convenience method for logging an 'info' message. 301 * 302 * @param message the message. 303 */ 304 public static void info(final Object message) { 305 log(LogTarget.INFO, message); 306 } 307 308 /** 309 * A convenience method for logging an 'info' message. 310 * 311 * @param message the message. 312 * @param e the exception. 313 */ 314 public static void info(final Object message, final Exception e) { 315 log(LogTarget.INFO, message, e); 316 } 317 318 /** 319 * A convenience method for logging a 'warning' message. 320 * 321 * @param message the message. 322 */ 323 public static void warn(final Object message) { 324 log(LogTarget.WARN, message); 325 } 326 327 /** 328 * A convenience method for logging a 'warning' message. 329 * 330 * @param message the message. 331 * @param e the exception. 332 */ 333 public static void warn(final Object message, final Exception e) { 334 log(LogTarget.WARN, message, e); 335 } 336 337 /** 338 * A convenience method for logging an 'error' message. 339 * 340 * @param message the message. 341 */ 342 public static void error(final Object message) { 343 log(LogTarget.ERROR, message); 344 } 345 346 /** 347 * A convenience method for logging an 'error' message. 348 * 349 * @param message the message. 350 * @param e the exception. 351 */ 352 public static void error(final Object message, final Exception e) { 353 log(LogTarget.ERROR, message, e); 354 } 355 356 /** 357 * Logs a message to the main log stream. All attached log targets will also 358 * receive this message. If the given log-level is higher than the given debug-level 359 * in the main config file, no logging will be done. 360 * 361 * @param level log level of the message. 362 * @param message text to be logged. 363 */ 364 protected void doLog(int level, final Object message) { 365 if (level > 3) { 366 level = 3; 367 } 368 if (level <= this.debuglevel) { 369 for (int i = 0; i < this.logTargets.length; i++) { 370 final LogTarget t = this.logTargets[i]; 371 t.log(level, message); 372 } 373 } 374 } 375 376 /** 377 * Logs a message to the main log stream. All attached log targets will also 378 * receive this message. If the given log-level is higher than the given debug-level 379 * in the main config file, no logging will be done. 380 * 381 * @param level log level of the message. 382 * @param message text to be logged. 383 */ 384 public static void log(final int level, final Object message) { 385 getInstance().doLog(level, message); 386 } 387 388 /** 389 * Logs a message to the main log stream. All attached logTargets will also 390 * receive this message. If the given log-level is higher than the given debug-level 391 * in the main config file, no logging will be done. 392 * <p/> 393 * The exception's stacktrace will be appended to the log-stream 394 * 395 * @param level log level of the message. 396 * @param message text to be logged. 397 * @param e the exception, which should be logged. 398 */ 399 public static void log(final int level, final Object message, final Exception e) { 400 getInstance().doLog(level, message, e); 401 } 402 403 /** 404 * Logs a message to the main log stream. All attached logTargets will also 405 * receive this message. If the given log-level is higher than the given debug-level 406 * in the main config file, no logging will be done. 407 * <p/> 408 * The exception's stacktrace will be appended to the log-stream 409 * 410 * @param level log level of the message. 411 * @param message text to be logged. 412 * @param e the exception, which should be logged. 413 */ 414 protected void doLog(int level, final Object message, final Exception e) { 415 if (level > 3) { 416 level = 3; 417 } 418 419 if (level <= this.debuglevel) { 420 for (int i = 0; i < this.logTargets.length; i++) { 421 final LogTarget t = this.logTargets[i]; 422 t.log(level, message, e); 423 } 424 } 425 } 426 427 /** 428 * Initializes the logging system. Implementors should 429 * override this method to supply their own log configuration. 430 */ 431 public void init() { 432 // this method is intentionally empty. 433 } 434 435 /** 436 * Returns true, if the log level allows debug messages to be 437 * printed. 438 * 439 * @return true, if messages with an log level of DEBUG are allowed. 440 */ 441 public static boolean isDebugEnabled() { 442 return getInstance().getDebuglevel() <= LogTarget.DEBUG; 443 } 444 445 /** 446 * Returns true, if the log level allows informational 447 * messages to be printed. 448 * 449 * @return true, if messages with an log level of INFO are allowed. 450 */ 451 public static boolean isInfoEnabled() { 452 return getInstance().getDebuglevel() <= LogTarget.INFO; 453 } 454 455 /** 456 * Returns true, if the log level allows warning messages to be 457 * printed. 458 * 459 * @return true, if messages with an log level of WARN are allowed. 460 */ 461 public static boolean isWarningEnabled() { 462 return getInstance().getDebuglevel() <= LogTarget.WARN; 463 } 464 465 /** 466 * Returns true, if the log level allows error messages to be 467 * printed. 468 * 469 * @return true, if messages with an log level of ERROR are allowed. 470 */ 471 public static boolean isErrorEnabled() { 472 return getInstance().getDebuglevel() <= LogTarget.ERROR; 473 } 474 475 /** 476 * Creates a log context. 477 * 478 * @param context the class (<code>null</code> not permitted). 479 * 480 * @return A log context. 481 */ 482 public static LogContext createContext(final Class context) { 483 return createContext(context.getName()); 484 } 485 486 /** 487 * Creates a log context. 488 * 489 * @param context the label for the context. 490 * 491 * @return A log context. 492 */ 493 public static LogContext createContext(final String context) { 494 return getInstance().internalCreateContext(context); 495 } 496 497 /** 498 * Creates a log context. 499 * 500 * @param context the name of the logging context (a common prefix). 501 * 502 * @return A log context. 503 */ 504 protected LogContext internalCreateContext(final String context) { 505 synchronized (this) { 506 LogContext ctx = (LogContext) this.logContexts.get(context); 507 if (ctx == null) { 508 ctx = new LogContext(context); 509 this.logContexts.put(context, ctx); 510 } 511 return ctx; 512 } 513 } 514 515 }