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.rolling;
15  
16  import java.io.File;
17  import java.util.concurrent.atomic.AtomicLong;
18  import java.util.concurrent.atomic.LongAdder;
19  
20  import ch.qos.logback.core.spi.LifeCycle;
21  
22  /**
23   * A <code>TriggeringPolicy</code> controls the conditions under which roll-over
24   * occurs. Such conditions include time of day, file size, an external event,
25   * the log request or a combination thereof.
26   *
27   * @author Ceki G&uuml;lc&uuml;
28   */
29  
30  public interface TriggeringPolicy<E> extends LifeCycle {
31  
32      /**
33       *  Return the {@link LengthCounter} instance associated with this triggering
34       *  policy. The returned value may be null.
35       *
36       * @return a LengthCounter instance, may be null
37       * @since 1.5.8
38       */
39      default LengthCounter getLengthCounter() {
40          return null;
41      }
42  
43      /**
44       * Should roll-over be triggered at this time?
45       * 
46       * @param activeFile A reference to the currently active log file.
47       * @param event      A reference to the current event.
48       * @return true if a roll-over should occur.
49       */
50      boolean isTriggeringEvent(final File activeFile, final E event);
51  }