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.sift; 015 016import ch.qos.logback.core.Appender; 017import ch.qos.logback.core.Context; 018import ch.qos.logback.core.CoreConstants; 019import ch.qos.logback.core.helpers.NOPAppender; 020import ch.qos.logback.core.joran.spi.JoranException; 021import ch.qos.logback.core.spi.AbstractComponentTracker; 022import ch.qos.logback.core.spi.ContextAwareImpl; 023 024/** 025 * Track appenders by key. When an appender is not used for longer than 026 * {@link #DEFAULT_TIMEOUT} it is stopped and removed. 027 * 028 * @author Tommy Becker 029 * @author Ceki Gulcu 030 * @author David Roussel 031 */ 032public class AppenderTracker<E> extends AbstractComponentTracker<Appender<E>> { 033 034 int nopaWarningCount = 0; 035 036 final Context context; 037 final AppenderFactory<E> appenderFactory; 038 final ContextAwareImpl contextAware; 039 040 public AppenderTracker(Context context, AppenderFactory<E> appenderFactory) { 041 super(); 042 this.context = context; 043 this.appenderFactory = appenderFactory; 044 this.contextAware = new ContextAwareImpl(context, this); 045 } 046 047 @Override 048 protected void processPriorToRemoval(Appender<E> component) { 049 component.stop(); 050 } 051 052 @Override 053 protected Appender<E> buildComponent(String key) { 054 Appender<E> appender = null; 055 try { 056 appender = appenderFactory.buildAppender(context, key); 057 } catch (JoranException je) { 058 contextAware.addError("Error while building appender with discriminating value [" + key + "]"); 059 } 060 if (appender == null) { 061 appender = buildNOPAppender(key); 062 } 063 064 return appender; 065 } 066 067 private NOPAppender<E> buildNOPAppender(String key) { 068 if (nopaWarningCount < CoreConstants.MAX_ERROR_COUNT) { 069 nopaWarningCount++; 070 contextAware.addError("Building NOPAppender for discriminating value [" + key + "]"); 071 } 072 NOPAppender<E> nopa = new NOPAppender<E>(); 073 nopa.setContext(context); 074 nopa.start(); 075 return nopa; 076 } 077 078 @Override 079 protected boolean isComponentStale(Appender<E> appender) { 080 return !appender.isStarted(); 081 } 082 083}