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    1   /*
    2    * Copyright 2001-2004 The Apache Software Foundation.
    3    *
    4    * Licensed under the Apache License, Version 2.0 (the "License");
    5    * you may not use this file except in compliance with the License.
    6    * You may obtain a copy of the License at
    7    *
    8    *      http://www.apache.org/licenses/LICENSE-2.0
    9    *
    10   * Unless required by applicable law or agreed to in writing, software
    11   * distributed under the License is distributed on an "AS IS" BASIS,
    12   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    13   * See the License for the specific language governing permissions and
    14   * limitations under the License.
    15   */
    16
    17  package org.apache.log4j.helpers;
    18
    19  /**
    20     This class used to output log statements from within the log4j package.
    21
    22     <p>Log4j components cannot make log4j logging calls. However, it is
    23     sometimes useful for the user to learn about what log4j is
    24     doing. You can enable log4j internal logging by defining the
    25     <b>log4j.configDebug</b> variable.
    26
    27     <p>All log4j internal debug calls go to <code>System.out</code>
    28     where as internal error messages are sent to
    29     <code>System.err</code>. All internal messages are prepended with
    30     the string "log4j: ".
    31
    32     @since 0.8.2
    33     @author Ceki G&uuml;lc&uuml;
    34  */
    35  public class LogLog {
    36
    37      /**
    38         Defining this value makes log4j print log4j-internal debug
    39         statements to <code>System.out</code>.
    40
    41        <p> The value of this string is <b>log4j.debug</b>.
    42
    43        <p>Note that the search for all option names is case sensitive.  */
    44      public static final String DEBUG_KEY = "log4j.debug";
    45
    46      /**
    47         Defining this value makes log4j components print log4j-internal
    48         debug statements to <code>System.out</code>.
    49
    50        <p> The value of this string is <b>log4j.configDebug</b>.
    51
    52        <p>Note that the search for all option names is case sensitive.
    53
    54        @deprecated Use {@link #DEBUG_KEY} instead.
    55      */
    56      public static final String CONFIG_DEBUG_KEY = "log4j.configDebug";
    57
    58      protected static boolean debugEnabled = false;
    59
    60      /**
    61         In quietMode not even errors generate any output.
    62       */
    63      private static boolean quietMode = false;
    64
    65      private static final String PREFIX = "log4j: ";
    66      private static final String ERR_PREFIX = "log4j:ERROR ";
    67      private static final String WARN_PREFIX = "log4j:WARN ";
    68
    69      static {
    70      }
    71
    72      /**
    73         Allows to enable/disable log4j internal logging.
    74       */
    75      static public void setInternalDebugging(boolean enabled) {
    76          debugEnabled = enabled;
    77      }
    78
    79      /**
    80         This method is used to output log4j internal debug
    81         statements. Output goes to <code>System.out</code>.
    82      */
    83      public static void debug(String msg) {
    84          if (debugEnabled && !quietMode) {
    85              System.out.println(PREFIX + msg);
    86          }
    87      }
    88
    89      /**
    90         This method is used to output log4j internal debug
    91         statements. Output goes to <code>System.out</code>.
    92      */
    93      public static void debug(String msg, Throwable t) {
    94          if (debugEnabled && !quietMode) {
    95              System.out.println(PREFIX + msg);
    96              if (t != null)
    97                  t.printStackTrace(System.out);
    98          }
    99      }
    100
    101     /**
    102        This method is used to output log4j internal error
    103        statements. There is no way to disable error statements.
    104        Output goes to <code>System.err</code>.
    105     */
    106     public static void error(String msg) {
    107         if (quietMode)
    108             return;
    109         System.err.println(ERR_PREFIX + msg);
    110     }
    111
    112     /**
    113        This method is used to output log4j internal error
    114        statements. There is no way to disable error statements.
    115        Output goes to <code>System.err</code>.
    116     */
    117     public static void error(String msg, Throwable t) {
    118         if (quietMode)
    119             return;
    120
    121         System.err.println(ERR_PREFIX + msg);
    122         if (t != null) {
    123             t.printStackTrace();
    124         }
    125     }
    126
    127     /**
    128        In quite mode no LogLog generates strictly no output, not even
    129        for errors.
    130
    131        @param quietMode A true for not
    132     */
    133     public static void setQuietMode(boolean quietMode) {
    134         LogLog.quietMode = quietMode;
    135     }
    136
    137     /**
    138        This method is used to output log4j internal warning
    139        statements. There is no way to disable warning statements.
    140        Output goes to <code>System.err</code>.  */
    141     public static void warn(String msg) {
    142         if (quietMode)
    143             return;
    144
    145         System.err.println(WARN_PREFIX + msg);
    146     }
    147
    148     /**
    149        This method is used to output log4j internal warnings. There is
    150        no way to disable warning statements.  Output goes to
    151        <code>System.err</code>.  */
    152     public static void warn(String msg, Throwable t) {
    153         if (quietMode)
    154             return;
    155
    156         System.err.println(WARN_PREFIX + msg);
    157         if (t != null) {
    158             t.printStackTrace();
    159         }
    160     }
    161 }