/*
* 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.filter;
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;
//HACK: Category is the last of the internal layers - pass this in as the class name
//in order for parsing to work correctly
private String className = "org.apache.log4j.Category";
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, className));
}
}
return Filter.NEUTRAL;
}
}