1 /*
2  * Copyright (c) 2016, 2018, Oracle and/or its affiliates. All rights reserved.
3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4  *
5  * This code is free software; you can redistribute it and/or modify it
6  * under the terms of the GNU General Public License version 2 only, as
7  * published by the Free Software Foundation.  Oracle designates this
8  * particular file as subject to the "Classpath" exception as provided
9  * by Oracle in the LICENSE file that accompanied this code.
10  *
11  * This code is distributed in the hope that it will be useful, but WITHOUT
12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
14  * version 2 for more details (a copy is included in the LICENSE file that
15  * accompanied this code).
16  *
17  * You should have received a copy of the GNU General Public License version
18  * 2 along with this work; if not, write to the Free Software Foundation,
19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20  *
21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22  * or visit www.oracle.com if you need additional information or have any
23  * questions.
24  */
25 
26 package jdk.jfr;
27 
28 
29 /**
30  * Callback interface to monitor Flight Recorder's life cycle.
31  *
32  * @since 9
33  */
34 public interface FlightRecorderListener {
35 
36     /**
37      * Receives notification when Flight Recorder is initialized.
38      * <p>
39      * This method is also be invoked when a listener is added to an already
40      * initialized Flight Recorder.
41      * <p>
42      * This method allows clients to implement their own initialization mechanism
43      * that is executed before a {@code FlightRecorder} instance is returned by
44      * {@code FlightRecorder#getFlightRecorder()}.
45      *
46      * @implNote This method should return as soon as possible, to avoid blocking
47      *           initialization of Flight Recorder. To avoid deadlocks or unexpected
48      *           behavior, this method should not call
49      *           {@link FlightRecorder#getFlightRecorder()} or start new recordings.
50      *
51      * @implSpec The default implementation of this method is empty.
52      *
53      * @param recorder Flight Recorder instance, not {@code null}
54      *
55      * @see FlightRecorder#addListener(FlightRecorderListener)
56      */
recorderInitialized(FlightRecorder recorder)57     default void recorderInitialized(FlightRecorder recorder) {
58     }
59 
60     /**
61      * Receives notification when the state of a recording changes.
62      * <p>
63      * Callback is invoked when a recording reaches the {@code RUNNING},
64      * {@code STOPPED} and {@code CLOSED} state.
65      *
66      * @implNote The implementation of this method should return as soon as possible
67      *           to avoid blocking normal operation of Flight Recorder.
68      *
69      * @implSpec The default implementation of this method is empty.
70      *
71      * @param recording the recording where the state change occurred, not
72      *        {@code null}
73      *
74      * @see FlightRecorder#addListener(FlightRecorderListener)
75      * @see RecordingState
76      *
77      */
recordingStateChanged(Recording recording)78     default void recordingStateChanged(Recording recording) {
79     }
80 }
81