cvs commit: logging-log4j/src/java/org/apache/log4j/varia LocationInfoFilter.java

[sd...@apache.org]

sdeboy      2004/12/19 10:01:07

  Added:       src/java/org/apache/log4j/varia LocationInfoFilter.java
  Log:
  LocationInfoFilter generates LocationInfo for an event only if the provided expression evaluates to true.
  
  Revision  Changes    Path
  1.1                  logging-log4j/src/java/org/apache/log4j/varia/LocationInfoFilter.java
  
  Index: LocationInfoFilter.java
  ===================================================================
  /*
   * Copyright 1999,2004 The Apache Software Foundation.
   * 
   * Licensed under the Apache License, Version 2.0 (the "License");
   * you may not use this file except in compliance with the License.
   * You may obtain a copy of the License at
   * 
   *      http://www.apache.org/licenses/LICENSE-2.0
   * 
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  
  package org.apache.log4j.varia;
  
  import org.apache.log4j.rule.ExpressionRule;
  import org.apache.log4j.rule.Rule;
  import org.apache.log4j.spi.Filter;
  import org.apache.log4j.spi.LoggingEvent;
  import org.apache.log4j.spi.location.LocationInfo;
  
  
  /**
   * Location information is usually specified at the appender level - all events associated 
   * with an appender either create and parse stack traces or they do not.  This is
   * an expensive operation and in some cases not needed for all events associated with
   * an appender.
   * 
   * This filter creates event-level location information only if the provided expression evaluates to true.
   * 
   * For information on expression syntax, see org.apache.log4j.rule.ExpressionRule
   * 
   * @author Scott Deboy sdeboy@apache.org
   */
  public class LocationInfoFilter extends Filter {
    boolean convertInFixToPostFix = true;
    String expression;
    Rule expressionRule;
  
    public void activateOptions() {
      expressionRule =
        ExpressionRule.getRule(expression, !convertInFixToPostFix);
    }
  
    public void setExpression(String expression) {
      this.expression = expression;
    }
  
    public String getExpression() {
      return expression;
    }
  
    public void setConvertInFixToPostFix(boolean convertInFixToPostFix) {
      this.convertInFixToPostFix = convertInFixToPostFix;
    }
  
    public boolean getConvertInFixToPostFix() {
      return convertInFixToPostFix;
    }
  
    /**
     * If this event does not already contain location information, 
     * evaluate the event against the expression.
     * 
     * If the expression evaluates to true, generate a LocationInfo instance 
     * by creating an exception and set this LocationInfo on the event.
     * 
     * Returns {@link Filter#NEUTRAL}
     */
    public int decide(LoggingEvent event) {
      if (!event.locationInformationExists()) {
        if (expressionRule.evaluate(event)) {
  	      Throwable t = new Exception();
  	      event.setLocationInformation(new LocationInfo(t, getClass().getName()));
        }
      }
      return Filter.NEUTRAL;
    }
  }
  
  
  

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