1 //
2 // ========================================================================
3 // Copyright (c) 1995-2015 Mort Bay Consulting Pty. Ltd.
4 // ------------------------------------------------------------------------
5 // All rights reserved. This program and the accompanying materials
6 // are made available under the terms of the Eclipse Public License v1.0
7 // and Apache License v2.0 which accompanies this distribution.
8 //
9 // The Eclipse Public License is available at
10 // http://www.eclipse.org/legal/epl-v10.html
11 //
12 // The Apache License v2.0 is available at
13 // http://www.opensource.org/licenses/apache2.0.php
14 //
15 // You may elect to redistribute this code under either of these licenses.
16 // ========================================================================
17 //
18
19 package org.eclipse.jetty.monitor.triggers;
20
21 import javax.management.MalformedObjectNameException;
22
23 /**
24 * GreaterThanAttrEventTrigger
25 * <p>
26 * Event trigger that polls a value of an MXBean attribute and
27 * checks if it is greater than specified min value.
28 * @param <TYPE> event trigger type
29 */
30 public class GreaterThanAttrEventTrigger<TYPE extends Comparable<TYPE>> extends AttrEventTrigger<TYPE>
31 {
32 protected final TYPE _min;
33
34 /* ------------------------------------------------------------ */
35 /**
36 * Construct event trigger and specify the MXBean attribute
37 * that will be polled by this event trigger as well as min
38 * value of the attribute.
39 *
40 * @param objectName object name of an MBean to be polled
41 * @param attributeName name of an MBean attribute to be polled
42 * @param min minimum value of the attribute
43 *
44 * @throws MalformedObjectNameException on bad object name
45 * @throws IllegalArgumentException on bad parameters
46 */
47 public GreaterThanAttrEventTrigger(String objectName, String attributeName, TYPE min)
48 throws MalformedObjectNameException, IllegalArgumentException
49 {
50 super(objectName,attributeName);
51
52 if (min == null)
53 throw new IllegalArgumentException("Value cannot be null");
54
55 _min = min;
56 }
57
58 /* ------------------------------------------------------------ */
59 /**
60 * Compare the value of the MXBean attribute being polling
61 * to check if it is greater than the min value.
62 *
63 * @see org.eclipse.jetty.monitor.triggers.AttrEventTrigger#match(java.lang.Comparable)
64 */
65 @Override
66 public boolean match(Comparable<TYPE> value)
67 {
68 return (value.compareTo(_min) > 0);
69 }
70
71 /* ------------------------------------------------------------ */
72 /**
73 * Returns the string representation of this event trigger
74 * in the format "min<name".
75 *
76 * @return string representation of the event trigger
77 *
78 * @see java.lang.Object#toString()
79 */
80 public String toString()
81 {
82 StringBuilder result = new StringBuilder();
83
84 result.append(_min);
85 result.append("<");
86 result.append(getNameString());
87
88 return result.toString();
89 }
90 }