1 /*
2 * Copyright (c) 2003, 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 sun.management;
27
28 import java.lang.management.MemoryUsage;
29 import java.util.Iterator;
30 import java.util.Map;
31 import java.util.HashMap;
32
33 /**
34 * An abstract sensor.
35 *
36 * <p>
37 * An {@code AbstractSensor} object consists of two attributes:
38 * <ul>
39 * <li>{@code on} is a boolean flag indicating if a sensor is
40 * triggered. This flag will be set or cleared by the
41 * component that owns the sensor.</li>
42 * <li>{@code count} is the total number of times that a sensor
43 * has been triggered.</li>
44 * </ul>
45 *
46 * @author Mandy Chung
47 * @since 1.5
48 */
49
50 public abstract class Sensor {
51 private final Object lock = new Object();
52 private final String name;
53 private long count; // VM-initialized to 0
54 private boolean on; // VM-initialized to false
55
56 /**
57 * Constructs a {@code Sensor} object.
58 *
59 * @param name The name of this sensor.
60 */
61 public Sensor(String name) {
62 this.name = name;
63 }
64
65 /**
66 * Returns the name of this sensor.
67 *
68 * @return the name of this sensor.
69 */
70 public String getName() {
71 return name;
72 }
73
74 /**
75 * Returns the total number of times that this sensor has been triggered.
76 *
77 * @return the total number of times that this sensor has been triggered.
78 */
79 public long getCount() {
80 synchronized (lock) {
81 return count;
82 }
83 }
84
85 /**
86 * Tests if this sensor is currently on.
87 *
88 * @return {@code true} if the sensor is currently on;
89 * {@code false} otherwise.
90 *
91 */
92 public boolean isOn() {
93 synchronized (lock) {
94 return on;
95 }
96 }
97
98 /**
99 * Triggers this sensor. This method first sets this sensor on
100 * and increments its sensor count.
101 */
102 public void trigger() {
103 synchronized (lock) {
104 on = true;
105 count++;
106 }
107 triggerAction();
108 }
109
110 /**
111 * Triggers this sensor. This method sets this sensor on
112 * and increments the count with the input {@code increment}.
113 */
114 public void trigger(int increment) {
115 synchronized (lock) {
116 on = true;
117 count += increment;
118 // Do something here...
119 }
120 triggerAction();
121 }
122
123 /**
124 * Triggers this sensor piggybacking a memory usage object.
125 * This method sets this sensor on
126 * and increments the count with the input {@code increment}.
127 */
128 public void trigger(int increment, MemoryUsage usage) {
129 synchronized (lock) {
130 on = true;
131 count += increment;
132 // Do something here...
133 }
134 triggerAction(usage);
135 }
136
137 /**
138 * Clears this sensor.
139 */
140 public void clear() {
141 synchronized (lock) {
142 on = false;
143 }
144 clearAction();
145 }
146
147
148 /**
149 * Clears this sensor
150 * and increments the count with the input {@code increment}.
151 */
152 public void clear(int increment) {
153 synchronized (lock) {
154 on = false;
155 count += increment;
156 }
157 clearAction();
158 }
159
160 public String toString() {
161 return "Sensor - " + getName() +
162 (isOn() ? " on " : " off ") +
163 " count = " + getCount();
164 }
165
166 abstract void triggerAction();
167 abstract void triggerAction(MemoryUsage u);
168 abstract void clearAction();
169 }