ndcfilter.java

SRI international 发布的OAA框架软件

package com.sri.oaa2.simplefac;

import org.apache.log4j.spi.Filter;
import org.apache.log4j.spi.LoggingEvent;
import org.apache.log4j.NDC;

/**
 * NDCFilter is used in conjunction with a DOMConfigurator in a configuration file:
 *
 * <log4j:configuration xmlns:log4j='http://jakarta.apache.org/log4j/'>
 *  <appender name="stdout" class="org.apache.log4j.ConsoleAppender">
 *    <param name="Target" value="System.out" />
 *    <layout class="org.apache.log4j.PatternLayout">
 *      <param name="ConversionPattern" value="%r %5p [%x-%t] (%c{2}) - %m%n" />
 *    </layout>
 *    <filter class="com.sri.oaa2.simplefac.NDCFilter">
 *      <param name="AcceptOnMatch" value="false" />
 *      <param name="StringToMatch" value="NDC_NO_DISPLAY" />
 *    </filter>
 *  </appender>
 *  ...
 *
 * In this case, based on the NDC at the time a log is made, no logs for which the
 * NDC contains the string NDC_NO_DISPLAY will be displayed.
 */
public class NDCFilter extends Filter 
{
  /**
   * Accept when the string matches, or don't
   */
  boolean acceptOnMatch = true;
  /**
   * The string to match
   */
  String stringToMatch = null;

  /**
   * Set the value of acceptOnMatch
   */
  public void setAcceptOnMatch(boolean a) 
  {
    acceptOnMatch = a;
  }
  
  /**
   * Does the filter accept the log when a match is found or not?
   */
  public boolean getAcceptOnMatch() 
  {
    return acceptOnMatch;
  }
  
  /**
   * Set the string that is used to discover a match
   */
  public void setStringToMatch(String s) 
  {
    stringToMatch = s;
  }
  
  /**
   * Get the string which is used as the filter
   */
  public String getStringToMatch() 
  {
    return stringToMatch;
  }

  /**
   * Accept or deny the LoggingEvent based on the value of the NDC
   */
  public int decide(LoggingEvent event) 
  {
    if(stringToMatch == null) {
      return Filter.NEUTRAL;
    }
    
    String ndcVal = NDC.get();
    if(ndcVal == null) {
      return Filter.NEUTRAL;
    }

    if(ndcVal.indexOf(getStringToMatch()) == -1) {
      return Filter.NEUTRAL;
    }
    else {
      if(getAcceptOnMatch()) {
        return Filter.ACCEPT;
      }
      else {
        return Filter.DENY;
      }
    }
  }
}