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1 /* |
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2 * Copyright 2005-2006 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.lang.model.element; |
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27 |
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28 |
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29 import java.util.List; |
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30 |
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31 import javax.lang.model.type.TypeMirror; |
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32 |
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33 |
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34 /** |
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35 * A visitor of the values of annotation type elements, using a |
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36 * variant of the visitor design pattern. Unlike a standard visitor |
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37 * which dispatches based on the concrete type of a member of a type |
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38 * hierarchy, this visitor dispatches based on the type of data |
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39 * stored; there are no distinct subclasses for storing, for example, |
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40 * {@code boolean} values versus {@code int} values. Classes |
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41 * implementing this interface are used to operate on a value when the |
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42 * type of that value is unknown at compile time. When a visitor is |
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43 * passed to a value's {@link AnnotationValue#accept accept} method, |
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44 * the <tt>visit<i>XYZ</i></tt> method applicable to that value is |
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45 * invoked. |
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46 * |
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47 * <p> Classes implementing this interface may or may not throw a |
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48 * {@code NullPointerException} if the additional parameter {@code p} |
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49 * is {@code null}; see documentation of the implementing class for |
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50 * details. |
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51 * |
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52 * <p> <b>WARNING:</b> It is possible that methods will be added to |
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53 * this interface to accommodate new, currently unknown, language |
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54 * structures added to future versions of the Java™ programming |
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55 * language. Therefore, visitor classes directly implementing this |
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56 * interface may be source incompatible with future versions of the |
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57 * platform. To avoid this source incompatibility, visitor |
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58 * implementations are encouraged to instead extend the appropriate |
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59 * abstract visitor class that implements this interface. However, an |
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60 * API should generally use this visitor interface as the type for |
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61 * parameters, return type, etc. rather than one of the abstract |
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62 * classes. |
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63 * |
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64 * @param <R> the return type of this visitor's methods |
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65 * @param <P> the type of the additional parameter to this visitor's methods. |
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66 * @author Joseph D. Darcy |
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67 * @author Scott Seligman |
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68 * @author Peter von der Ahé |
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69 * @since 1.6 |
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70 */ |
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71 public interface AnnotationValueVisitor<R, P> { |
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72 /** |
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73 * Visits an annotation value. |
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74 * @param av the value to visit |
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75 * @param p a visitor-specified parameter |
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76 * @return a visitor-specified result |
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77 */ |
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78 R visit(AnnotationValue av, P p); |
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79 |
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80 /** |
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81 * A convenience method equivalent to {@code v.visit(av, null)}. |
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82 * @param av the value to visit |
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83 * @return a visitor-specified result |
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84 */ |
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85 R visit(AnnotationValue av); |
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86 |
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87 /** |
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88 * Visits a {@code boolean} value in an annotation. |
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89 * @param b the value being visited |
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90 * @param p a visitor-specified parameter |
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91 * @return the result of the visit |
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92 */ |
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93 R visitBoolean(boolean b, P p); |
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94 |
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95 /** |
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96 * Visits a {@code byte} value in an annotation. |
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97 * @param b the value being visited |
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98 * @param p a visitor-specified parameter |
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99 * @return the result of the visit |
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100 */ |
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101 R visitByte(byte b, P p); |
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102 |
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103 /** |
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104 * Visits a {@code char} value in an annotation. |
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105 * @param c the value being visited |
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106 * @param p a visitor-specified parameter |
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107 * @return the result of the visit |
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108 */ |
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109 R visitChar(char c, P p); |
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110 |
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111 /** |
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112 * Visits a {@code double} value in an annotation. |
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113 * @param d the value being visited |
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114 * @param p a visitor-specified parameter |
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115 * @return the result of the visit |
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116 */ |
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117 R visitDouble(double d, P p); |
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118 |
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119 /** |
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120 * Visits a {@code float} value in an annotation. |
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121 * @param f the value being visited |
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122 * @param p a visitor-specified parameter |
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123 * @return the result of the visit |
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124 */ |
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125 R visitFloat(float f, P p); |
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126 |
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127 /** |
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128 * Visits an {@code int} value in an annotation. |
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129 * @param i the value being visited |
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130 * @param p a visitor-specified parameter |
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131 * @return the result of the visit |
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132 */ |
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133 R visitInt(int i, P p); |
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134 |
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135 /** |
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136 * Visits a {@code long} value in an annotation. |
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137 * @param i the value being visited |
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138 * @param p a visitor-specified parameter |
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139 * @return the result of the visit |
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140 */ |
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141 R visitLong(long i, P p); |
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142 |
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143 /** |
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144 * Visits a {@code short} value in an annotation. |
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145 * @param s the value being visited |
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146 * @param p a visitor-specified parameter |
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147 * @return the result of the visit |
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148 */ |
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149 R visitShort(short s, P p); |
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150 |
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151 /** |
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152 * Visits a string value in an annotation. |
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153 * @param s the value being visited |
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154 * @param p a visitor-specified parameter |
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155 * @return the result of the visit |
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156 */ |
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157 R visitString(String s, P p); |
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158 |
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159 /** |
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160 * Visits a type value in an annotation. |
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161 * @param t the value being visited |
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162 * @param p a visitor-specified parameter |
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163 * @return the result of the visit |
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164 */ |
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165 R visitType(TypeMirror t, P p); |
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166 |
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167 /** |
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168 * Visits an {@code enum} value in an annotation. |
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169 * @param c the value being visited |
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170 * @param p a visitor-specified parameter |
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171 * @return the result of the visit |
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172 */ |
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173 R visitEnumConstant(VariableElement c, P p); |
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174 |
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175 /** |
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176 * Visits an annotation value in an annotation. |
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177 * @param a the value being visited |
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178 * @param p a visitor-specified parameter |
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179 * @return the result of the visit |
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180 */ |
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181 R visitAnnotation(AnnotationMirror a, P p); |
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182 |
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183 /** |
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184 * Visits an array value in an annotation. |
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185 * @param vals the value being visited |
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186 * @param p a visitor-specified parameter |
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187 * @return the result of the visit |
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188 */ |
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189 R visitArray(List<? extends AnnotationValue> vals, P p); |
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190 |
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191 /** |
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192 * Visits an unknown kind of annotation value. |
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193 * This can occur if the language evolves and new kinds |
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194 * of value can be stored in an annotation. |
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195 * @param av the unknown value being visited |
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196 * @param p a visitor-specified parameter |
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197 * @return the result of the visit |
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198 * @throws UnknownAnnotationValueException |
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199 * a visitor implementation may optionally throw this exception |
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200 */ |
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201 R visitUnknown(AnnotationValue av, P p); |
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202 } |