1 //
2 // ========================================================================
3 // Copyright (c) 1995-2014 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 java.util.Map;
22 import java.util.concurrent.ConcurrentHashMap;
23
24 import javax.management.MBeanServerConnection;
25 import javax.management.MalformedObjectNameException;
26 import javax.management.ObjectName;
27 import javax.management.openmbean.CompositeData;
28
29 import org.eclipse.jetty.monitor.JMXMonitor;
30 import org.eclipse.jetty.monitor.jmx.EventState;
31 import org.eclipse.jetty.monitor.jmx.EventTrigger;
32 import org.eclipse.jetty.util.log.Log;
33 import org.eclipse.jetty.util.log.Logger;
34
35
36 /* ------------------------------------------------------------ */
37 /**
38 * AttrEventTrigger
39 *
40 * Event trigger that polls a value of an MXBean attribute
41 * and matches every invocation of this trigger. It can be
42 * used to send notifications of the value of an attribute
43 * of the MXBean being polled at a certain interval, or as
44 * a base class for the event triggers that match the
45 * value of an attribute of the MXBean being polled against
46 * some specified criteria.
47 */
48 public class AttrEventTrigger<TYPE extends Comparable<TYPE>>
49 extends EventTrigger
50 {
51 private static final Logger LOG = Log.getLogger(AttrEventTrigger.class);
52
53 private final ObjectName _nameObject;
54
55 protected final String _objectName;
56 protected final String _attributeName;
57 protected Map<Long, EventState<TYPE>> _states;
58
59 /* ------------------------------------------------------------ */
60 /**
61 * Construct event trigger and specify the MXBean attribute
62 * that will be polled by this event trigger.
63 *
64 * @param objectName object name of an MBean to be polled
65 * @param attributeName name of an MBean attribute to be polled
66 *
67 * @throws MalformedObjectNameException
68 * @throws IllegalArgumentException
69 */
70 public AttrEventTrigger(String objectName, String attributeName)
71 throws MalformedObjectNameException, IllegalArgumentException
72 {
73 if (objectName == null)
74 throw new IllegalArgumentException("Object name cannot be null");
75 if (attributeName == null)
76 throw new IllegalArgumentException("Attribute name cannot be null");
77
78 _states = new ConcurrentHashMap<Long,EventState<TYPE>>();
79
80 _objectName = objectName;
81 _attributeName = attributeName;
82
83 _nameObject = new ObjectName(_objectName);
84 }
85
86 /* ------------------------------------------------------------ */
87 /**
88 * Construct event trigger and specify the MXBean attribute
89 * that will be polled by this event trigger.
90 *
91 * @param nameObject object name of an MBean to be polled
92 * @param attributeName name of an MBean attribute to be polled
93 *
94 * @throws IllegalArgumentException
95 */
96 public AttrEventTrigger(ObjectName nameObject, String attributeName)
97 throws IllegalArgumentException
98 {
99 if (nameObject == null)
100 throw new IllegalArgumentException("Object name cannot be null");
101 if (attributeName == null)
102 throw new IllegalArgumentException("Attribute name cannot be null");
103
104 _states = new ConcurrentHashMap<Long,EventState<TYPE>>();
105
106 _objectName = nameObject.toString();
107 _attributeName = attributeName;
108
109 _nameObject = nameObject;
110 }
111
112 /* ------------------------------------------------------------ */
113 /**
114 * Verify if the event trigger conditions are in the
115 * appropriate state for an event to be triggered.
116 * This event trigger uses the match(Comparable<TYPE>)
117 * method to compare the value of the MXBean attribute
118 * to the conditions specified by the subclasses.
119 *
120 * @see org.eclipse.jetty.monitor.jmx.EventTrigger#match(long)
121 */
122 @SuppressWarnings("unchecked")
123 public final boolean match(long timestamp)
124 throws Exception
125 {
126 MBeanServerConnection serverConnection = JMXMonitor.getServiceConnection();
127
128 TYPE value = null;
129 try
130 {
131 int pos = _attributeName.indexOf('.');
132 if (pos < 0)
133 value = (TYPE)serverConnection.getAttribute(_nameObject,_attributeName);
134 else
135 value = getValue((CompositeData)serverConnection.getAttribute(_nameObject, _attributeName.substring(0, pos)),
136 _attributeName.substring(pos+1));
137 }
138 catch (Exception ex)
139 {
140 LOG.debug(ex);
141 }
142
143 boolean result = false;
144 if (value != null)
145 {
146 result = match(value);
147
148 if (result || getSaveAll())
149 {
150 _states.put(timestamp,
151 new EventState<TYPE>(this.getID(), this.getNameString(), value));
152 }
153 }
154
155 return result;
156 }
157
158
159 /* ------------------------------------------------------------ */
160 /**
161 * Verify if the event trigger conditions are in the
162 * appropriate state for an event to be triggered.
163 * Allows subclasses to override the default behavior
164 * that matches every invocation of this trigger
165 */
166 public boolean match(Comparable<TYPE> value)
167 {
168 return true;
169 }
170
171 /* ------------------------------------------------------------ */
172 /**
173 * Retrieve the event state associated with specified invocation
174 * of the event trigger match method.
175 *
176 * @param timestamp time stamp associated with invocation
177 * @return event state or null if not found
178 *
179 * @see org.eclipse.jetty.monitor.jmx.EventTrigger#getState(long)
180 */
181 @Override
182 public final EventState<TYPE> getState(long timestamp)
183 {
184 return _states.get(timestamp);
185 }
186
187 /* ------------------------------------------------------------ */
188 /**
189 * Returns the string representation of this event trigger
190 * in the format "[object_name:attribute_name]".
191 *
192 * @return string representation of the event trigger
193 *
194 * @see java.lang.Object#toString()
195 */
196 public String toString()
197 {
198 return getNameString();
199 }
200
201 /* ------------------------------------------------------------ */
202 /**
203 * Returns the string representation of this event trigger
204 * in the format "[object_name:attribute_name]". Allows
205 * subclasses to override the name string used to identify
206 * this event trigger in the event state object as well as
207 * string representation of the subclasses.
208 *
209 * @return string representation of the event trigger
210 */
211 protected String getNameString()
212 {
213 StringBuilder result = new StringBuilder();
214
215 result.append('[');
216 result.append(_objectName);
217 result.append(":");
218 result.append(_attributeName);
219 result.append("]");
220
221 return result.toString();
222 }
223
224 protected boolean getSaveAll()
225 {
226 return true;
227 }
228
229 protected TYPE getValue(CompositeData compValue, String fieldName)
230 {
231 int pos = fieldName.indexOf('.');
232 if (pos < 0)
233 return (TYPE)compValue.get(fieldName);
234 else
235 return getValue((CompositeData)compValue.get(fieldName.substring(0, pos)),
236 fieldName.substring(pos+1));
237
238 }
239 }