1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License (the "License").
6  * You may not use this file except in compliance with the License.
7  *
8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9  * or http://www.opensolaris.org/os/licensing.
10  * See the License for the specific language governing permissions
11  * and limitations under the License.
12  *
13  * When distributing Covered Code, include this CDDL HEADER in each
14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15  * If applicable, add the following below this CDDL HEADER, with the
16  * fields enclosed by brackets "[]" replaced with your own identifying
17  * information: Portions Copyright [yyyy] [name of copyright owner]
18  *
19  * CDDL HEADER END
20  */
21 
22 /*
23  * Copyright 2006 Sun Microsystems, Inc.  All rights reserved.
24  * Use is subject to license terms.
25  *
26  * ident	"%Z%%M%	%I%	%E% SMI"
27  */
28 package org.opensolaris.os.dtrace;
29 
30 import java.util.EventListener;
31 
32 /**
33  * Listener for data generated by a single DTrace {@link Consumer}.
34  *
35  * @author Tom Erickson
36  */
37 public interface ConsumerListener extends EventListener {
38     /**
39      * Called whenever a DTrace probe fires (that is, once for each
40      * instance of {@link ProbeData} generated by DTrace).  Identifies
41      * the probe and provides data generated by the probe's actions.  To
42      * terminate the consumer in the event of unexpected data, throw a
43      * {@link ConsumerException} from this method.
44      *
45      * @throws ConsumerException if the implementation should terminate
46      * the running consumer
47      */
48     public void dataReceived(DataEvent e) throws ConsumerException;
49 
50     /**
51      * Called when traced data is dropped because of inadequate buffer
52      * space.  To terminate the consumer in the event of a drop, throw
53      * a {@link ConsumerException} from this method.
54      *
55      * @throws ConsumerException if the implementation should terminate
56      * the running consumer
57      */
58     public void dataDropped(DropEvent e) throws ConsumerException;
59 
60     /**
61      * Called when an error is encountered in the native DTrace library
62      * while tracing probe data.  To terminate the consumer, throw a
63      * {@link ConsumerException} from this method.
64      *
65      * @throws ConsumerException if the implementation should terminate
66      * the running consumer
67      */
68     public void errorEncountered(ErrorEvent e) throws ConsumerException;
69 
70     /**
71      * Called when the state of a target process changes.  To terminate
72      * the consumer in the event of unexpected process state, throw a
73      * {@link ConsumerException} from this method.
74      *
75      * @throws ConsumerException if the implementation should terminate
76      * the running consumer
77      * @see Consumer#createProcess(String command)
78      * @see Consumer#grabProcess(int pid)
79      */
80     public void processStateChanged(ProcessEvent e) throws ConsumerException;
81 
82     /**
83      * Called once when the source {@link Consumer} is successfully
84      * started in response to {@link Consumer#go()}.
85      *
86      * @see #consumerStopped(ConsumerEvent e)
87      */
88     public void consumerStarted(ConsumerEvent e);
89 
90     /**
91      * Called once when the source {@link Consumer} is stopped,
92      * indicating that this listener should expect no further events.
93      * Called only if there was a prior call to {@link
94      * #consumerStarted(ConsumerEvent e) consumerStarted()}, that is,
95      * only if the consumer was successfully started by a call to {@link
96      * Consumer#go()}.  Guaranteed to be called whether the consumer was
97      * stopped by request (via {@link Consumer#stop()}), terminated
98      * normally as a result of the DTrace {@code exit()} action or the
99      * completion of all target processes, or terminated abnormally
100      * because of an exception.  It is necessary to call {@link
101      * Consumer#close()} to release any system resources still held by
102      * the stopped consumer.
103      *
104      * @see #consumerStarted(ConsumerEvent e)
105      */
106     public void consumerStopped(ConsumerEvent e);
107 
108     /**
109      * Called when the source {@link Consumer} wakes up to process its
110      * buffer of traced probe data.
111      *
112      * @see #intervalEnded(ConsumerEvent e)
113      */
114     public void intervalBegan(ConsumerEvent e);
115 
116     /**
117      * Called when the source {@link Consumer} finishes processing its
118      * buffer of traced probe data and is about to sleep until the next
119      * interval.  The rate of consumption may be controlled with the
120      * {@link Option#switchrate switchrate} and {@link Option#aggrate
121      * aggrate} options (see {@link Consumer#setOption(String option,
122      * String value)}).
123      *
124      * @see #intervalBegan(ConsumerEvent e)
125      */
126     public void intervalEnded(ConsumerEvent e);
127 }
128