001/** 002 * Logback: the reliable, generic, fast and flexible logging framework. 003 * Copyright (C) 1999-2015, QOS.ch. All rights reserved. 004 * 005 * This program and the accompanying materials are dual-licensed under 006 * either the terms of the Eclipse Public License v1.0 as published by 007 * the Eclipse Foundation 008 * 009 * or (per the licensee's choosing) 010 * 011 * under the terms of the GNU Lesser General Public License version 2.1 012 * as published by the Free Software Foundation. 013 */ 014package ch.qos.logback.core.filter; 015 016import ch.qos.logback.core.boolex.EvaluationException; 017import ch.qos.logback.core.boolex.EventEvaluator; 018import ch.qos.logback.core.spi.FilterReply; 019 020/** 021 * The value of the {@link #onMatch} and {@link #onMismatch} attributes is set 022 * to {@link FilterReply#NEUTRAL}, so that a badly configured evaluator filter 023 * does not disturb the functioning of the filter chain. 024 * 025 * <p> 026 * It is expected that one of the two attributes will have its value changed to 027 * {@link FilterReply#ACCEPT} or {@link FilterReply#DENY}. That way, it is 028 * possible to decide if a given result must be returned after the evaluation 029 * either failed or succeeded. 030 * 031 * 032 * <p> 033 * For more information about filters, please refer to the online manual at 034 * http://logback.qos.ch/manual/filters.html 035 * 036 * @author Ceki Gülcü 037 * @author Sébastien Pennec 038 */ 039public class EvaluatorFilter<E> extends AbstractMatcherFilter<E> { 040 041 EventEvaluator<E> evaluator; 042 043 @Override 044 public void start() { 045 if (evaluator != null) { 046 super.start(); 047 } else { 048 addError("No evaluator set for filter " + this.getName()); 049 } 050 } 051 052 public EventEvaluator<E> getEvaluator() { 053 return evaluator; 054 } 055 056 public void setEvaluator(EventEvaluator<E> evaluator) { 057 this.evaluator = evaluator; 058 } 059 060 public FilterReply decide(E event) { 061 // let us not throw an exception 062 // see also bug #17. 063 if (!isStarted() || !evaluator.isStarted()) { 064 return FilterReply.NEUTRAL; 065 } 066 try { 067 if (evaluator.evaluate(event)) { 068 return onMatch; 069 } else { 070 return onMismatch; 071 } 072 } catch (EvaluationException e) { 073 addError("Evaluator " + evaluator.getName() + " threw an exception", e); 074 return FilterReply.NEUTRAL; 075 } 076 } 077 078}