LogLog xref

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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    /**
    48       Defining this value makes log4j components print log4j-internal
    49       debug statements to <code>System.out</code>.
    50
    51      <p> The value of this string is <b>log4j.configDebug</b>.
    52
    53      <p>Note that the search for all option names is case sensitive.
    54
    55      @deprecated Use {@link #DEBUG_KEY} instead.
    56    */
    57    public static final String CONFIG_DEBUG_KEY="log4j.configDebug";
    58
    59    protected static boolean debugEnabled = false;
    60
    61    /**
    62       In quietMode not even errors generate any output.
    63     */
    64    private static boolean quietMode = false;
    65
    66    private static final String PREFIX = "log4j: ";
    67    private static final String ERR_PREFIX = "log4j:ERROR ";
    68    private static final String WARN_PREFIX = "log4j:WARN ";
    69
    70    static {
    71    }
    72
    73    /**
    74       Allows to enable/disable log4j internal logging.
    75     */
    76    static
    77    public
    78    void setInternalDebugging(boolean enabled) {
    79      debugEnabled = enabled;
    80    }
    81
    82    /**
    83       This method is used to output log4j internal debug
    84       statements. Output goes to <code>System.out</code>.
    85    */
    86    public
    87    static
    88    void debug(String msg) {
    89      if(debugEnabled && !quietMode) {
    90        System.out.println(PREFIX+msg);
    91      }
    92    }
    93
    94    /**
    95       This method is used to output log4j internal debug
    96       statements. Output goes to <code>System.out</code>.
    97    */
    98    public
    99    static
    100   void debug(String msg, Throwable t) {
    101     if(debugEnabled && !quietMode) {
    102       System.out.println(PREFIX+msg);
    103       if(t != null)
    104 	t.printStackTrace(System.out);
    105     }
    106   }
    107
    108
    109   /**
    110      This method is used to output log4j internal error
    111      statements. There is no way to disable error statements.
    112      Output goes to <code>System.err</code>.
    113   */
    114   public
    115   static
    116   void error(String msg) {
    117     if(quietMode)
    118       return;
    119     System.err.println(ERR_PREFIX+msg);
    120   }
    121
    122   /**
    123      This method is used to output log4j internal error
    124      statements. There is no way to disable error statements.
    125      Output goes to <code>System.err</code>.
    126   */
    127   public
    128   static
    129   void error(String msg, Throwable t) {
    130     if(quietMode)
    131       return;
    132
    133     System.err.println(ERR_PREFIX+msg);
    134     if(t != null) {
    135       t.printStackTrace();
    136     }
    137   }
    138
    139   /**
    140      In quite mode no LogLog generates strictly no output, not even
    141      for errors.
    142
    143      @param quietMode A true for not
    144   */
    145   public
    146   static
    147   void setQuietMode(boolean quietMode) {
    148     LogLog.quietMode = quietMode;
    149   }
    150
    151   /**
    152      This method is used to output log4j internal warning
    153      statements. There is no way to disable warning statements.
    154      Output goes to <code>System.err</code>.  */
    155   public
    156   static
    157   void warn(String msg) {
    158     if(quietMode)
    159       return;
    160
    161     System.err.println(WARN_PREFIX+msg);
    162   }
    163
    164   /**
    165      This method is used to output log4j internal warnings. There is
    166      no way to disable warning statements.  Output goes to
    167      <code>System.err</code>.  */
    168   public
    169   static
    170   void warn(String msg, Throwable t) {
    171     if(quietMode)
    172       return;
    173
    174     System.err.println(WARN_PREFIX+msg);
    175     if(t != null) {
    176       t.printStackTrace();
    177     }
    178   }
    179 }