1 /**
2 * Logback: the reliable, generic, fast and flexible logging framework.
3 * Copyright (C) 1999-2015, QOS.ch. All rights reserved.
4 *
5 * This program and the accompanying materials are dual-licensed under
6 * either the terms of the Eclipse Public License v1.0 as published by
7 * the Eclipse Foundation
8 *
9 * or (per the licensee's choosing)
10 *
11 * under the terms of the GNU Lesser General Public License version 2.1
12 * as published by the Free Software Foundation.
13 */
14 package ch.qos.logback.core.sift;
15
16 import ch.qos.logback.core.spi.LifeCycle;
17
18 /**
19 * Implement this interface in order to compute a discriminating value for a
20 * given event of type <E>.
21 *
22 * <p>
23 * The returned value can depend on any data available at the time of the call,
24 * including data contained within the currently running thread.
25 *
26 * @author Ceki Gülcü
27 *
28 * @param <E>
29 */
30 public interface Discriminator<E> extends LifeCycle {
31
32 /**
33 * Given event 'e' return a discriminating value.
34 *
35 * @param e
36 * @return
37 */
38 String getDiscriminatingValue(E e);
39
40 /**
41 * The key or variable name under which the discriminating value should be
42 * exported into the host environment.
43 *
44 * @return
45 */
46 String getKey();
47 }