1 /**
2 * Logback: the reliable, generic, fast and flexible logging framework.
3 * Copyright (C) 1999-2011, 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>The returned value can depend on any data available at the time of the
23 * call, including data contained within the currently running thread.
24 *
25 * @author Ceki Gülcü
26 *
27 * @param <E>
28 */
29 public interface Discriminator<E> extends LifeCycle {
30
31 /**
32 * Given event 'e' return a discriminating value.
33 *
34 * @param e
35 * @return
36 */
37 String getDiscriminatingValue(E e);
38
39 /**
40 * The key or variable name under which the discriminating value should be
41 * exported into the host environment.
42 *
43 * @return
44 */
45 String getKey();
46 }