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1 /* |
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2 * Copyright (c) 2009, 2010, Oracle and/or its affiliates. All rights reserved. |
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3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
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4 * |
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5 * This code is free software; you can redistribute it and/or modify it |
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6 * under the terms of the GNU General Public License version 2 only, as |
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7 * published by the Free Software Foundation. Oracle designates this |
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8 * particular file as subject to the "Classpath" exception as provided |
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9 * by Oracle in the LICENSE file that accompanied this code. |
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10 * |
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11 * This code is distributed in the hope that it will be useful, but WITHOUT |
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12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
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13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
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14 * version 2 for more details (a copy is included in the LICENSE file that |
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15 * accompanied this code). |
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16 * |
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17 * You should have received a copy of the GNU General Public License version |
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18 * 2 along with this work; if not, write to the Free Software Foundation, |
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19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
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20 * |
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21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
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22 * or visit www.oracle.com if you need additional information or have any |
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23 * questions. |
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24 */ |
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25 |
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26 |
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27 package com.sun.org.glassfish.external.amx; |
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28 |
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29 import java.util.Set; |
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30 import javax.management.MBeanServer; |
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31 import javax.management.MBeanServerConnection; |
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32 import javax.management.MBeanServerNotification; |
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33 import javax.management.Notification; |
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34 import javax.management.NotificationListener; |
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35 import javax.management.ObjectName; |
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36 import java.util.concurrent.CountDownLatch; |
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37 |
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38 import static com.sun.org.glassfish.external.amx.AMX.*; |
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39 |
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40 /** |
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41 * Listens for registration of MBeans of various types. |
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42 * Intended usage is for subsystems to lazy-load only when the Parent |
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43 * MBean is registered. |
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44 */ |
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45 @com.sun.org.glassfish.external.arc.Taxonomy(stability = com.sun.org.glassfish.external.arc.Stability.UNCOMMITTED) |
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46 public class MBeanListener<T extends MBeanListener.Callback> implements NotificationListener |
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47 { |
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48 private static void debug(final Object o) { System.out.println( "" + o ); } |
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49 |
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50 /** listen for MBeans in a given domain of a given type[name] |
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51 OR an ObjectName (below) */ |
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52 private final String mJMXDomain; |
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53 private final String mType; |
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54 private final String mName; |
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55 |
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56 /** mType and mName should be null if mObjectName is non-null, and vice versa */ |
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57 private final ObjectName mObjectName; |
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58 |
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59 private final MBeanServerConnection mMBeanServer; |
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60 |
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61 private final T mCallback; |
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62 |
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63 public String toString() |
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64 { |
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65 return "MBeanListener: ObjectName=" + mObjectName + ", type=" + mType + ", name=" + mName; |
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66 } |
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67 |
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68 public String getType() |
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69 { |
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70 return mType; |
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71 } |
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72 |
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73 public String getName() |
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74 { |
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75 return mName; |
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76 } |
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77 |
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78 public MBeanServerConnection getMBeanServer() |
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79 { |
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80 return mMBeanServer; |
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81 } |
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82 |
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83 /** Callback interface. */ |
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84 public interface Callback |
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85 { |
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86 public void mbeanRegistered(final ObjectName objectName, final MBeanListener listener); |
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87 public void mbeanUnregistered(final ObjectName objectName, final MBeanListener listener); |
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88 } |
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89 |
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90 /** |
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91 Default callback implementation, can be subclassed if needed |
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92 Remembers only the last MBean that was seen. |
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93 */ |
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94 public static class CallbackImpl implements MBeanListener.Callback |
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95 { |
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96 private volatile ObjectName mRegistered = null; |
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97 private volatile ObjectName mUnregistered = null; |
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98 private final boolean mStopAtFirst; |
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99 |
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100 public CallbackImpl() { |
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101 this(true); |
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102 } |
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103 |
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104 public CallbackImpl(final boolean stopAtFirst) |
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105 { |
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106 mStopAtFirst = stopAtFirst; |
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107 } |
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108 |
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109 public ObjectName getRegistered() { return mRegistered; } |
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110 public ObjectName getUnregistered() { return mUnregistered; } |
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111 |
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112 protected final CountDownLatch mLatch = new CountDownLatch(1); |
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113 |
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114 /** Optional: wait for the CountDownLatch to fire |
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115 If used, the subclass should countDown() the latch when the |
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116 appropriate event happens |
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117 */ |
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118 public void await() |
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119 { |
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120 try |
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121 { |
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122 mLatch.await(); // wait until BootAMXMBean is ready |
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123 } |
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124 catch (InterruptedException e) |
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125 { |
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126 throw new RuntimeException(e); |
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127 } |
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128 } |
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129 |
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130 public void mbeanRegistered(final ObjectName objectName, final MBeanListener listener) |
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131 { |
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132 mRegistered = objectName; |
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133 if ( mStopAtFirst ) |
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134 { |
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135 listener.stopListening(); |
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136 } |
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137 } |
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138 public void mbeanUnregistered(final ObjectName objectName, final MBeanListener listener) |
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139 { |
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140 mUnregistered = objectName; |
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141 if ( mStopAtFirst ) |
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142 { |
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143 listener.stopListening(); |
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144 } |
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145 } |
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146 } |
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147 |
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148 public T getCallback() |
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149 { |
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150 return mCallback; |
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151 } |
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152 |
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153 /** |
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154 * Listener for a specific MBean. |
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155 * Caller must call {@link #start} to start listening. |
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156 * @param server |
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157 * @param objectName |
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158 * @param callback |
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159 */ |
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160 public MBeanListener( |
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161 final MBeanServerConnection server, |
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162 final ObjectName objectName, |
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163 final T callback) |
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164 { |
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165 mMBeanServer = server; |
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166 mObjectName = objectName; |
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167 mJMXDomain = null; |
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168 mType = null; |
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169 mName = null; |
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170 mCallback = callback; |
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171 } |
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172 |
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173 /** |
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174 * Listener for all MBeans of specified type, with or without a name. |
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175 * Caller must call {@link #start} to start listening. |
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176 * @param server |
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177 * @param type type of the MBean (as found in the ObjectName) |
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178 * @param callback |
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179 */ |
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180 public MBeanListener( |
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181 final MBeanServerConnection server, |
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182 final String domain, |
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183 final String type, |
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184 final T callback) |
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185 { |
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186 this(server, domain, type, null, callback); |
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187 } |
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188 |
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189 /** |
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190 * Listener for MBeans of specified type, with specified name (or any name |
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191 * if null is passed for the name). |
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192 * Caller must call {@link #start} to start listening. |
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193 * @param server |
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194 * @param type type of the MBean (as found in the ObjectName) |
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195 * @param name name of the MBean, or null if none |
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196 * @param callback |
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197 */ |
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198 public MBeanListener( |
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199 final MBeanServerConnection server, |
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200 final String domain, |
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201 final String type, |
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202 final String name, |
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203 final T callback) |
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204 { |
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205 mMBeanServer = server; |
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206 mJMXDomain = domain; |
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207 mType = type; |
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208 mName = name; |
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209 mObjectName = null; |
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210 mCallback = callback; |
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211 } |
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212 |
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213 |
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214 private boolean isRegistered( final MBeanServerConnection conn, final ObjectName objectName ) |
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215 { |
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216 try |
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217 { |
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218 return conn.isRegistered(objectName); |
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219 } |
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220 catch (final Exception e) |
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221 { |
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222 throw new RuntimeException(e); |
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223 } |
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224 } |
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225 |
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226 /** |
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227 Start listening. If the required MBean(s) are already present, the callback |
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228 will be synchronously made before returning. It is also possible that the |
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229 callback could happen twice for the same MBean. |
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230 */ |
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231 public void startListening() |
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232 { |
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233 // race condition: must listen *before* looking for existing MBeans |
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234 try |
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235 { |
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236 mMBeanServer.addNotificationListener( AMXUtil.getMBeanServerDelegateObjectName(), this, null, this); |
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237 } |
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238 catch (final Exception e) |
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239 { |
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240 throw new RuntimeException("Can't add NotificationListener", e); |
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241 } |
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242 |
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243 if ( mObjectName != null ) |
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244 { |
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245 if ( isRegistered(mMBeanServer, mObjectName) ) |
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246 { |
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247 mCallback.mbeanRegistered(mObjectName, this); |
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248 } |
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249 } |
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250 else |
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251 { |
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252 // query for AMX MBeans of the requisite type |
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253 String props = TYPE_KEY + "=" + mType; |
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254 if (mName != null) |
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255 { |
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256 props = props + "," + NAME_KEY + mName; |
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257 } |
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258 |
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259 final ObjectName pattern = AMXUtil.newObjectName(mJMXDomain + ":" +props); |
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260 try |
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261 { |
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262 final Set<ObjectName> matched = mMBeanServer.queryNames(pattern, null); |
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263 for (final ObjectName objectName : matched) |
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264 { |
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265 mCallback.mbeanRegistered(objectName, this); |
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266 } |
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267 } |
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268 catch( final Exception e ) |
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269 { |
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270 throw new RuntimeException(e); |
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271 } |
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272 } |
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273 } |
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274 |
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275 |
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276 /** unregister the listener */ |
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277 public void stopListening() |
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278 { |
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279 try |
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280 { |
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281 mMBeanServer.removeNotificationListener( AMXUtil.getMBeanServerDelegateObjectName(), this); |
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282 } |
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283 catch (final Exception e) |
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284 { |
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285 throw new RuntimeException("Can't remove NotificationListener " + this, e); |
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286 } |
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287 } |
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288 |
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289 public void handleNotification( |
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290 final Notification notifIn, |
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291 final Object handback) |
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292 { |
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293 if (notifIn instanceof MBeanServerNotification) |
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294 { |
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295 final MBeanServerNotification notif = (MBeanServerNotification) notifIn; |
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296 final ObjectName objectName = notif.getMBeanName(); |
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297 |
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298 boolean match = false; |
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299 if ( mObjectName != null && mObjectName.equals(objectName) ) |
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300 { |
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301 match = true; |
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302 } |
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303 else if ( objectName.getDomain().equals( mJMXDomain ) ) |
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304 { |
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305 if ( mType != null && mType.equals(objectName.getKeyProperty(TYPE_KEY)) ) |
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306 { |
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307 final String mbeanName = objectName.getKeyProperty(NAME_KEY); |
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308 if (mName != null && mName.equals(mbeanName)) |
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309 { |
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310 match = true; |
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311 } |
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312 } |
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313 } |
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314 |
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315 if ( match ) |
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316 { |
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317 final String notifType = notif.getType(); |
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318 if (MBeanServerNotification.REGISTRATION_NOTIFICATION.equals(notifType)) |
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319 { |
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320 mCallback.mbeanRegistered(objectName, this); |
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321 } |
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322 else if (MBeanServerNotification.UNREGISTRATION_NOTIFICATION.equals(notifType)) |
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323 { |
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324 mCallback.mbeanUnregistered(objectName, this); |
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325 } |
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326 } |
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327 } |
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328 } |
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329 |
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330 } |