src/java/org/apache/log4j/varia/LevelRangeFilter.java

/*
 * Copyright (C) The Apache Software Foundation. All rights reserved.
 *
 * This software is published under the terms of the Apache Software
 * License version 1.1, a copy of which has been included with this
 * distribution in the LICENSE.txt file.  */

package org.apache.log4j.varia;

import org.apache.log4j.Level;
import org.apache.log4j.spi.Filter;
import org.apache.log4j.spi.LoggingEvent;
import org.apache.log4j.helpers.LogLog;
import org.apache.log4j.helpers.OptionConverter;

/**
   This is a very simple filter based on level matching, which can be
   used to reject messages with priorities outside a certain range.
   
   <p>The filter admits three options <b>LevelMin</b>, <b>LevelMax</b>
   and <b>AcceptOnMatch</b>.

   <p>If the level of the {@link LoggingEvent} is not between Min and Max
   (inclusive), then {@link Filter#DENY} is returned.
   
   <p> If the Logging event level is within the specified range, then if
   <b>AcceptOnMatch</b> is true, {@link Filter#ACCEPT} is returned, and if
   <b>AcceptOnMatch</b> is false, {@link Filter#NEUTRAL} is returned.
   
   <p>If <code>LevelMin</code>w is not defined, then there is no
   minimum acceptable level (ie a level is never rejected for
   being too "low"/unimportant).  If <code>LevelMax</code> is not
   defined, then there is no maximum acceptable level (ie a
   level is never rejected for beeing too "high"/important).

   <p>Refer to the {@link
   org.apache.log4j.AppenderSkeleton#setThreshold setThreshold} method
   available to <code>all</code> appenders extending {@link
   org.apache.log4j.AppenderSkeleton} for a more convenient way to
   filter out events by level.

   @author Simon Kitching
   @author based on code by Ceki G&uuml;lc&uuml; 
*/
public class LevelRangeFilter extends Filter {

  /**
     Do we return ACCEPT when a match occurs. Default is
     <code>false</code>, so that later filters get run by default  */
  boolean acceptOnMatch = false;

  Level levelMin;
  Level levelMax;

 
  /**
     Return the decision of this filter.
   */
  public
  int decide(LoggingEvent event) {
    if(this.levelMin != null) {
      if (event.getLevel().isGreaterOrEqual(levelMin) == false) {
        // level of event is less than minimum
        return Filter.DENY;
      }
    }

    if(this.levelMax != null) {
      if (event.getLevel().toInt() > levelMax.toInt()) {
        // level of event is greater than maximum
        // Alas, there is no Level.isGreater method. and using
        // a combo of isGreaterOrEqual && !Equal seems worse than
        // checking the int values of the level objects..
        return Filter.DENY;
      }
    }

    if (acceptOnMatch) {
      // this filter set up to bypass later filters and always return
      // accept if level in range
      return Filter.ACCEPT;
    }
    else {
      // event is ok for this filter; allow later filters to have a look..
      return Filter.NEUTRAL;
    }
  }

 /**
     Get the value of the <code>LevelMax</code> option.  */
  public
  Level getLevelMax() {
    return levelMax;
  }


  /**
     Get the value of the <code>LevelMin</code> option.  */
  public
  Level getLevelMin() {
    return levelMin;
  }

  /**
     Get the value of the <code>AcceptOnMatch</code> option.
   */
  public
  boolean getAcceptOnMatch() {
    return acceptOnMatch;
  }

  /**
     Set the <code>LevelMax</code> option.
   */
  public
  void setLevelMax(Level levelMax) {
    this.levelMax =  levelMax;
  }

  /**
     Set the <code>LevelMin</code> option.
   */
  public
  void setLevelMin(Level levelMin) {
    this.levelMin =  levelMin;
  }

  /**
     Set the <code>AcceptOnMatch</code> option.
   */  
  public 
  void setAcceptOnMatch(boolean acceptOnMatch) {
    this.acceptOnMatch = acceptOnMatch;
  }
}