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.spi.LifeCycle; 017 018/** 019 * Implement this interface in order to compute a discriminating value for a 020 * given event of type <E>. 021 * 022 * <p> 023 * The returned value can depend on any data available at the time of the call, 024 * including data contained within the currently running thread. 025 * 026 * @author Ceki Gülcü 027 * 028 * @param <E> 029 */ 030public interface Discriminator<E> extends LifeCycle { 031 032 /** 033 * Given event 'e' return a discriminating value. 034 * 035 * @param e 036 * @return 037 */ 038 String getDiscriminatingValue(E e); 039 040 /** 041 * The key or variable name under which the discriminating value should be 042 * exported into the host environment. 043 * 044 * @return 045 */ 046 String getKey(); 047}