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 * A <tt>AbstractSensor</tt> object consists of two attributes:
38 * <ul>
39 * <li><tt>on</tt> 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><tt>count</tt> 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 Object lock;
52 private String name;
53 private long count;
54 private boolean on;
55
56 /**
57 * Constructs a <tt>Sensor</tt> object.
58 *
59 * @param name The name of this sensor.
60 */
61 public Sensor(String name) {
62 this.name = name;
63 this.count = 0;
64 this.on = false;
65 this.lock = new Object();
66 }
67
68 /**
69 * Returns the name of this sensor.
70 *
71 * @return the name of this sensor.
72 */
73 public String getName() {
74 return name;
75 }
76
77 /**
78 * Returns the total number of times that this sensor has been triggered.
79 *
80 * @return the total number of times that this sensor has been triggered.
81 */
82 public long getCount() {
83 synchronized (lock) {
84 return count;
85 }
86 }
87
88 /**
89 * Tests if this sensor is currently on.
90 *
91 * @return <tt>true</tt> if the sensor is currently on;
92 * <tt>false</tt> otherwise.
93 *
94 */
95 public boolean isOn() {
96 synchronized (lock) {
97 return on;
98 }
99 }
100
101 /**
102 * Triggers this sensor. This method first sets this sensor on
103 * and increments its sensor count.
104 */
105 public void trigger() {
106 synchronized (lock) {
107 on = true;
108 count++;
109 }
110 triggerAction();
111 }
112
113 /**
114 * Triggers this sensor. This method sets this sensor on
115 * and increments the count with the input <tt>increment</tt>.
116 */
117 public void trigger(int increment) {
118 synchronized (lock) {
119 on = true;
120 count += increment;
121 // Do something here...
122 }
123 triggerAction();
124 }
125
126 /**
127 * Triggers this sensor piggybacking a memory usage object.
128 * This method sets this sensor on
129 * and increments the count with the input <tt>increment</tt>.
130 */
131 public void trigger(int increment, MemoryUsage usage) {
132 synchronized (lock) {
133 on = true;
134 count += increment;
135 // Do something here...
136 }
137 triggerAction(usage);
138 }
139
140 /**
141 * Clears this sensor.
142 */
143 public void clear() {
144 synchronized (lock) {
145 on = false;
146 }
147 clearAction();
148 }
149
150
151 /**
152 * Clears this sensor
153 * and increments the count with the input <tt>increment</tt>.
154 */
155 public void clear(int increment) {
156 synchronized (lock) {
157 on = false;
158 count += increment;
159 }
160 clearAction();
161 }
162
163 public String toString() {
164 return "Sensor - " + getName() +
165 (isOn() ? " on " : " off ") +
166 " count = " + getCount();
167 }
168
169 abstract void triggerAction();
170 abstract void triggerAction(MemoryUsage u);
171 abstract void clearAction();
172 }