Logger xref

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    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  package org.apache.log4j;
    19
    20  import org.apache.log4j.spi.LoggerFactory;
    21
    22
    23  /**
    24    This is the central class in the log4j package. Most logging
    25    operations, except configuration, are done through this class.
    26
    27    @since log4j 1.2
    28
    29    @author Ceki G&uuml;lc&uuml; */
    30  public class Logger extends Category {
    31
    32    /**
    33       The fully qualified name of the Logger class. See also the
    34       getFQCN method. */
    35    private static final String FQCN = Logger.class.getName();
    36
    37
    38    protected
    39    Logger(String name) {
    40      super(name);
    41    }
    42
    43    /**
    44      Log a message object with the {@link Level#FINE FINE} level which
    45      is just an alias for the {@link Level#DEBUG DEBUG} level.
    46
    47      <p>This method first checks if this category is <code>DEBUG</code>
    48      enabled by comparing the level of this category with the {@link
    49      Level#DEBUG DEBUG} level. If this category is
    50      <code>DEBUG</code> enabled, then it converts the message object
    51      (passed as parameter) to a string by invoking the appropriate
    52      {@link org.apache.log4j.or.ObjectRenderer}. It then proceeds to call all the
    53      registered appenders in this category and also higher in the
    54      hierarchy depending on the value of the additivity flag.
    55
    56      <p><b>WARNING</b> Note that passing a {@link Throwable} to this
    57      method will print the name of the <code>Throwable</code> but no
    58      stack trace. To print a stack trace use the {@link #debug(Object,
    59      Throwable)} form instead.
    60
    61      @param message the message object to log. */
    62    //public
    63    //void fine(Object message) {
    64    //  if(repository.isDisabled(Level.DEBUG_INT))
    65    //	return;
    66    //  if(Level.DEBUG.isGreaterOrEqual(this.getChainedLevel())) {
    67    //	forcedLog(FQCN, Level.DEBUG, message, null);
    68    //  }
    69    //}
    70
    71
    72    /**
    73     Log a message object with the <code>FINE</code> level including
    74     the stack trace of the {@link Throwable} <code>t</code> passed as
    75     parameter.
    76
    77     <p>See {@link #fine(Object)} form for more detailed information.
    78
    79     @param message the message object to log.
    80     @param t the exception to log, including its stack trace.  */
    81    //public
    82    //void fine(Object message, Throwable t) {
    83    //  if(repository.isDisabled(Level.DEBUG_INT))
    84    //	return;
    85    //  if(Level.DEBUG.isGreaterOrEqual(this.getChainedLevel()))
    86    //	forcedLog(FQCN, Level.FINE, message, t);
    87    //}
    88
    89    /**
    90     * Retrieve a logger named according to the value of the
    91     * <code>name</code> parameter. If the named logger already exists,
    92     * then the existing instance will be returned. Otherwise, a new
    93     * instance is created.
    94     *
    95     * <p>By default, loggers do not have a set level but inherit it
    96     * from their neareast ancestor with a set level. This is one of the
    97     * central features of log4j.
    98     *
    99     * @param name The name of the logger to retrieve.
    100   */
    101   static
    102   public
    103   Logger getLogger(String name) {
    104     return LogManager.getLogger(name);
    105   }
    106
    107   /**
    108    * Shorthand for <code>getLogger(clazz.getName())</code>.
    109    *
    110    * @param clazz The name of <code>clazz</code> will be used as the
    111    * name of the logger to retrieve.  See {@link #getLogger(String)}
    112    * for more detailed information.
    113    */
    114   static
    115   public
    116   Logger getLogger(Class clazz) {
    117     return LogManager.getLogger(clazz.getName());
    118   }
    119
    120
    121   /**
    122    * Return the root logger for the current logger repository.
    123    * <p>
    124    * The {@link #getName Logger.getName()} method for the root logger always returns
    125    * string value: "root". However, calling
    126    * <code>Logger.getLogger("root")</code> does not retrieve the root
    127    * logger but a logger just under root named "root".
    128    * <p>
    129    * In other words, calling this method is the only way to retrieve the
    130    * root logger.
    131    */
    132   public
    133   static
    134   Logger getRootLogger() {
    135     return LogManager.getRootLogger();
    136   }
    137
    138   /**
    139      Like {@link #getLogger(String)} except that the type of logger
    140      instantiated depends on the type returned by the {@link
    141      LoggerFactory#makeNewLoggerInstance} method of the
    142      <code>factory</code> parameter.
    143
    144      <p>This method is intended to be used by sub-classes.
    145
    146      @param name The name of the logger to retrieve.
    147
    148      @param factory A {@link LoggerFactory} implementation that will
    149      actually create a new Instance.
    150
    151      @since 0.8.5 */
    152   public
    153   static
    154   Logger getLogger(String name, LoggerFactory factory) {
    155     return LogManager.getLogger(name, factory);
    156   }
    157
    158     /**
    159      * Log a message object with the {@link org.apache.log4j.Level#TRACE TRACE} level.
    160      *
    161      * @param message the message object to log.
    162      * @see #debug(Object) for an explanation of the logic applied.
    163      * @since 1.2.12
    164      */
    165     public void trace(Object message) {
    166       if (repository.isDisabled(Level.TRACE_INT)) {
    167         return;
    168       }
    169
    170       if (Level.TRACE.isGreaterOrEqual(this.getEffectiveLevel())) {
    171         forcedLog(FQCN, Level.TRACE, message, null);
    172       }
    173     }
    174
    175     /**
    176      * Log a message object with the <code>TRACE</code> level including the
    177      * stack trace of the {@link Throwable}<code>t</code> passed as parameter.
    178      *
    179      * <p>
    180      * See {@link #debug(Object)} form for more detailed information.
    181      * </p>
    182      *
    183      * @param message the message object to log.
    184      * @param t the exception to log, including its stack trace.
    185      * @since 1.2.12
    186      */
    187     public void trace(Object message, Throwable t) {
    188       if (repository.isDisabled(Level.TRACE_INT)) {
    189         return;
    190       }
    191
    192       if (Level.TRACE.isGreaterOrEqual(this.getEffectiveLevel())) {
    193         forcedLog(FQCN, Level.TRACE, message, t);
    194       }
    195     }
    196
    197     /**
    198      * Check whether this category is enabled for the TRACE  Level.
    199      * @since 1.2.12
    200      *
    201      * @return boolean - <code>true</code> if this category is enabled for level
    202      *         TRACE, <code>false</code> otherwise.
    203      */
    204     public boolean isTraceEnabled() {
    205         if (repository.isDisabled(Level.TRACE_INT)) {
    206             return false;
    207           }
    208
    209           return Level.TRACE.isGreaterOrEqual(this.getEffectiveLevel());
    210     }
    211
    212 }