1 /* |
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2 * Copyright 2008 Sun Microsystems, Inc. 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. Sun designates this |
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8 * particular file as subject to the "Classpath" exception as provided |
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9 * by Sun 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, |
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22 * CA 95054 USA or visit www.sun.com if you need additional information or |
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23 * have any questions. |
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24 */ |
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25 |
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26 package javax.management; |
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27 |
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28 import javax.management.openmbean.CompositeData; |
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29 |
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30 /** |
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31 * <p>A customizable exception that has an optional error code string and |
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32 * payload. By using this exception in an MBean, you can avoid requiring |
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33 * clients of the MBean to have custom exception classes.</p> |
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34 * |
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35 * <p>An instance of this class has an optional {@linkplain #getErrorCode() |
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36 * error code}, and an optional {@linkplain #getUserData() payload} known as |
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37 * {@code userData}. This allows you to distinguish between different |
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38 * sorts of exception while still using this class for all of them.</p> |
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39 * |
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40 * <p>To produce a suitable {@code userData}, it is often simplest to use |
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41 * the MXBean framework. For example, suppose you want to convey a severity |
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42 * and a subsystem with your exception, which are respectively an int and a |
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43 * String. You could define a class like this:</p> |
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44 * |
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45 * <pre> |
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46 * public class ExceptionDetails { |
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47 * private final int severity; |
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48 * private final String subsystem; |
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49 * |
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50 * {@link java.beans.ConstructorProperties @ConstructorProperties}(<!-- |
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51 * -->{"severity", "subsystem"}) |
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52 * public ExceptionDetails(int severity, String subsystem) { |
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53 * this.severity = severity; |
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54 * this.subsystem = subsystem; |
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55 * } |
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56 * |
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57 * public int getSeverity() { |
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58 * return severity; |
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59 * } |
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60 * |
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61 * public String getSubsystem() { |
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62 * return subsystem; |
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63 * } |
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64 * } |
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65 * </pre> |
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66 * |
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67 * <p>Then you can get the MXBean framework to transform {@code ExceptionDetails} |
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68 * into {@link CompositeData} like this:</p> |
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69 * |
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70 * <pre> |
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71 * static final <!-- |
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72 * -->{@link javax.management.openmbean.MXBeanMapping MXBeanMapping} <!-- |
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73 * -->exceptionDetailsMapping = <!-- |
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74 * -->{@link javax.management.openmbean.MXBeanMappingFactory#DEFAULT |
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75 * MXBeanMappingFactory.DEFAULT}.mappingForType( |
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76 * ExceptionDetails.class, MXBeanMappingFactory.DEFAULT); |
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77 * |
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78 * public static GenericMBeanException newGenericMBeanException( |
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79 * String message, String errorCode, int severity, String subsystem) { |
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80 * ExceptionDetails details = new ExceptionDetails(severity, subsystem); |
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81 * CompositeData userData = (CompositeData) |
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82 * exceptionDetailsMapping.toOpenValue(details); |
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83 * return new GenericMBeanException( |
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84 * message, errorCode, userData, (Throwable) null); |
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85 * } |
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86 * |
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87 * ... |
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88 * throw newGenericMBeanException(message, errorCode, 25, "foosystem"); |
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89 * </pre> |
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90 * |
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91 * <p>A client that knows the {@code ExceptionDetails} class can convert |
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92 * back from the {@code userData} of a {@code GenericMBeanException} |
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93 * that was generated as above:</p> |
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94 * |
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95 * <pre> |
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96 * ... |
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97 * try { |
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98 * mbeanProxy.foo(); |
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99 * } catch (GenericMBeanException e) { |
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100 * CompositeData userData = e.getUserData(); |
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101 * ExceptionDetails details = (ExceptionDetails) |
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102 * exceptionDetailsMapping.fromOpenValue(userData); |
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103 * System.out.println("Exception Severity: " + details.getSeverity()); |
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104 * } |
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105 * ... |
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106 * </pre> |
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107 * |
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108 * <p>The Descriptor field <a href="Descriptor.html#exceptionErrorCodes"><!-- |
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109 * -->exceptionErrorCodes</a> can be used to specify in the |
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110 * {@link MBeanOperationInfo} for an operation what the possible |
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111 * {@linkplain #getErrorCode() error codes} are when that operation throws |
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112 * {@code GenericMBeanException}. It can also be used in an {@link |
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113 * MBeanConstructorInfo} or {@link MBeanAttributeInfo} to specify what the |
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114 * possible error codes are for {@code GenericMBeanException} when invoking |
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115 * that constructor or getting that attribute, respectively. The field |
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116 * <a href="Descriptor.html#setExceptionErrorCodes"><!-- |
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117 * -->setExceptionErrorCodes</a> can be used to specify what the possible |
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118 * error codes are when setting an attribute.</p> |
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119 * |
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120 * <p>You may want to use the {@link DescriptorKey @DescriptorKey} facility |
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121 * to define annotations that allow you to specify the error codes. If you |
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122 * define...</p> |
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123 * |
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124 * <pre> |
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125 * {@link java.lang.annotation.Documented @Documented} |
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126 * {@link java.lang.annotation.Target @Target}(ElementType.METHOD) |
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127 * {@link java.lang.annotation.Retention @Retention}(RetentionPolicy.RUNTIME) |
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128 * public @interface ErrorCodes { |
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129 * @DescriptorKey("exceptionErrorCodes") |
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130 * String[] value(); |
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131 * } |
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132 * </pre> |
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133 * |
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134 * <p>...then you can write MBean interfaces like this...</p> |
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135 * |
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136 * <pre> |
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137 * public interface FooMBean { // or FooMXBean |
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138 * @ErrorCodes({"com.example.bad", "com.example.worse"}) |
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139 * public void foo() throws GenericMBeanException; |
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140 * } |
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141 * </pre> |
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142 * |
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143 * <p>The Descriptor field <a href="Descriptor.html#exceptionUserDataTypes"><!-- |
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144 * -->exceptionUserDataTypes</a> can be used to specify in the |
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145 * {@link MBeanOperationInfo} for an operation what the possible types of |
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146 * {@linkplain #getUserData() userData} are when that operation throws |
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147 * {@code GenericMBeanException}. It is an array of |
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148 * {@link javax.management.openmbean.CompositeType CompositeType} values |
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149 * describing the possible {@link CompositeData} formats. This field can also be used |
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150 * in an {@link MBeanConstructorInfo} or {@link MBeanAttributeInfo} to specify |
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151 * the possible types of user data for {@code GenericMBeanException} when |
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152 * invoking that constructor or getting that attribute, respectively. The |
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153 * field |
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154 * <a href="Descriptor.html#setExceptionUserDataTypes">setExceptionUserDataTypes</a> |
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155 * can be used to specify the possible types of user data for exceptions when |
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156 * setting an attribute. If a Descriptor has both {@code exceptionErrorCodes} |
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157 * and {@code exceptionUserDataTypes} then the two arrays should be the |
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158 * same size; each pair of corresponding elements describes one kind |
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159 * of exception. Similarly for {@code setExceptionErrorCodes} and {@code |
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160 * setExceptionUserDataTypes}. |
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161 * |
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162 * |
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163 * <h4>Serialization</h4> |
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164 * |
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165 * <p>For compatibility reasons, instances of this class are serialized as |
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166 * instances of {@link MBeanException}. Special logic in that class converts |
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167 * them back to instances of this class at deserialization time. If the |
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168 * serialized object is deserialized in an earlier version of the JMX API |
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169 * that does not include this class, then it will appear as just an {@code |
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170 * MBeanException} and the error code or userData will not be available.</p> |
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171 * |
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172 * @since 1.7 |
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173 */ |
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174 public class GenericMBeanException extends MBeanException { |
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175 private static final long serialVersionUID = -1560202003985932823L; |
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176 |
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177 /** |
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178 * <p>Constructs a new {@code GenericMBeanException} with the given |
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179 * detail message. This constructor is |
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180 * equivalent to {@link #GenericMBeanException(String, String, |
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181 * CompositeData, Throwable) GenericMBeanException(message, "", |
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182 * null, null)}.</p> |
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183 * |
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184 * @param message the exception detail message. |
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185 */ |
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186 public GenericMBeanException(String message) { |
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187 this(message, "", null, null); |
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188 } |
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189 |
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190 /** |
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191 * <p>Constructs a new {@code GenericMBeanException} with the given |
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192 * detail message and cause. This constructor is |
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193 * equivalent to {@link #GenericMBeanException(String, String, |
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194 * CompositeData, Throwable) GenericMBeanException(message, "", |
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195 * null, cause)}.</p> |
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196 * |
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197 * @param message the exception detail message. |
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198 * @param cause the cause of this exception. Can be null. |
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199 */ |
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200 public GenericMBeanException(String message, Throwable cause) { |
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201 this(message, "", null, cause); |
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202 } |
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203 |
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204 /** |
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205 * <p>Constructs a new {@code GenericMBeanException} with the given |
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206 * detail message, error code, and user data. This constructor is |
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207 * equivalent to {@link #GenericMBeanException(String, String, |
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208 * CompositeData, Throwable) GenericMBeanException(message, errorCode, |
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209 * userData, null)}.</p> |
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210 * |
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211 * @param message the exception detail message. |
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212 * @param errorCode the exception error code. Specifying a null value |
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213 * is equivalent to specifying an empty string. It is recommended to use |
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214 * the same reverse domain name convention as package names, for example |
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215 * "com.example.foo.UnexpectedFailure". There is no requirement that the |
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216 * error code be a syntactically valid Java identifier. |
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217 * @param userData extra information about the exception. Can be null. |
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218 */ |
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219 public GenericMBeanException( |
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220 String message, String errorCode, CompositeData userData) { |
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221 this(message, errorCode, userData, null); |
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222 } |
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223 |
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224 /** |
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225 * <p>Constructs a new {@code GenericMBeanException} with the given |
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226 * detail message, error code, user data, and cause.</p> |
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227 * |
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228 * @param message the exception detail message. |
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229 * @param errorCode the exception error code. Specifying a null value |
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230 * is equivalent to specifying an empty string. It is recommended to use |
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231 * the same reverse domain name convention as package names, for example |
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232 * "com.example.foo.UnexpectedFailure". There is no requirement that the |
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233 * error code be a syntactically valid Java identifier. |
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234 * @param userData extra information about the exception. Can be null. |
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235 * @param cause the cause of this exception. Can be null. |
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236 */ |
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237 public GenericMBeanException( |
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238 String message, String errorCode, CompositeData userData, |
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239 Throwable cause) { |
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240 super(message, (errorCode == null) ? "" : errorCode, userData, cause); |
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241 } |
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242 |
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243 /** |
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244 * <p>Returns the error code of this exception.</p> |
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245 * |
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246 * @return the error code. This value is never null. |
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247 */ |
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248 public String getErrorCode() { |
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249 return errorCode; |
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250 } |
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251 |
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252 /** |
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253 * <p>Returns the userData of this exception.</p> |
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254 * |
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255 * @return the userData. Can be null. |
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256 */ |
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257 public CompositeData getUserData() { |
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258 return userData; |
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259 } |
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260 |
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261 /** |
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262 * <p>Instances of this class are serialized as instances of |
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263 * {@link MBeanException}. {@code MBeanException} has private fields that can |
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264 * not be set by its public constructors. They can only be set in objects |
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265 * returned by this method. When an {@code MBeanException} instance is |
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266 * deserialized, if those fields are present then its {@code readResolve} |
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267 * method will substitute a {@code GenericMBeanException} equivalent to |
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268 * this one.</p> |
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269 */ |
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270 Object writeReplace() { |
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271 MBeanException x = new MBeanException( |
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272 getMessage(), errorCode, userData, getCause()); |
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273 x.setStackTrace(this.getStackTrace()); |
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274 return x; |
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275 } |
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276 } |
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