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1 /* |
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2 * Copyright (c) 2015, 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 * This file is available under and governed by the GNU General Public |
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28 * License version 2 only, as published by the Free Software Foundation. |
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29 * However, the following notice accompanied the original version of this |
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30 * file, and Oracle licenses the original version of this file under the BSD |
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31 * license: |
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32 */ |
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33 /* |
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34 Copyright 2009-2015 Attila Szegedi |
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35 |
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36 Licensed under both the Apache License, Version 2.0 (the "Apache License") |
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37 and the BSD License (the "BSD License"), with licensee being free to |
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38 choose either of the two at their discretion. |
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39 |
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40 You may not use this file except in compliance with either the Apache |
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41 License or the BSD License. |
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42 |
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43 If you choose to use this file in compliance with the Apache License, the |
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44 following notice applies to you: |
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45 |
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46 You may obtain a copy of the Apache License at |
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47 |
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48 http://www.apache.org/licenses/LICENSE-2.0 |
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49 |
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50 Unless required by applicable law or agreed to in writing, software |
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51 distributed under the License is distributed on an "AS IS" BASIS, |
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52 WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or |
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53 implied. See the License for the specific language governing |
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54 permissions and limitations under the License. |
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55 |
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56 If you choose to use this file in compliance with the BSD License, the |
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57 following notice applies to you: |
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58 |
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59 Redistribution and use in source and binary forms, with or without |
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60 modification, are permitted provided that the following conditions are |
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61 met: |
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62 * Redistributions of source code must retain the above copyright |
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63 notice, this list of conditions and the following disclaimer. |
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64 * Redistributions in binary form must reproduce the above copyright |
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65 notice, this list of conditions and the following disclaimer in the |
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66 documentation and/or other materials provided with the distribution. |
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67 * Neither the name of the copyright holder nor the names of |
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68 contributors may be used to endorse or promote products derived from |
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69 this software without specific prior written permission. |
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70 |
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71 THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS |
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72 IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED |
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73 TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A |
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74 PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL COPYRIGHT HOLDER |
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75 BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR |
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76 CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF |
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77 SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR |
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78 BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, |
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79 WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR |
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80 OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF |
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81 ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
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82 */ |
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83 |
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84 package jdk.dynalink.linker.support; |
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85 |
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86 import java.lang.invoke.MethodHandle; |
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87 import java.lang.invoke.MethodHandles; |
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88 import java.lang.invoke.MethodType; |
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89 import jdk.dynalink.DynamicLinkerFactory; |
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90 import jdk.dynalink.linker.MethodHandleTransformer; |
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91 |
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92 /** |
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93 * Default implementation for a |
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94 * {@link DynamicLinkerFactory#setInternalObjectsFilter(MethodHandleTransformer)} |
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95 * that delegates to a pair of filtering method handles. It takes a method |
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96 * handle of {@code Object(Object)} type for filtering parameter values and |
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97 * another one of the same type for filtering return values. It applies them as |
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98 * parameter and return value filters on method handles passed to its |
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99 * {@link #transform(MethodHandle)} method, on those parameters and return values |
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100 * that are declared to have type {@link Object}. Also handles |
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101 * {@link MethodHandle#isVarargsCollector() method handles that support variable |
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102 * arity calls} with a last {@code Object[]} parameter. You can broadly think of |
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103 * the parameter filter as being a wrapping method for exposing internal runtime |
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104 * objects wrapped into an adapter with some public interface, and the return |
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105 * value filter as being its inverse unwrapping method. |
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106 */ |
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107 public class DefaultInternalObjectFilter implements MethodHandleTransformer { |
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108 private static final MethodHandle FILTER_VARARGS = new Lookup(MethodHandles.lookup()).findStatic( |
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109 DefaultInternalObjectFilter.class, "filterVarArgs", MethodType.methodType(Object[].class, MethodHandle.class, Object[].class)); |
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110 |
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111 private final MethodHandle parameterFilter; |
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112 private final MethodHandle returnFilter; |
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113 private final MethodHandle varArgFilter; |
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114 |
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115 /** |
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116 * Creates a new filter. |
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117 * @param parameterFilter the filter for method parameters. Must be of type |
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118 * {@code Object(Object)}, or {@code null}. |
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119 * @param returnFilter the filter for return values. Must be of type |
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120 * {@code Object(Object)}, or {@code null}. |
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121 * @throws IllegalArgumentException if one or both filters are not of the |
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122 * expected type. |
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123 */ |
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124 public DefaultInternalObjectFilter(final MethodHandle parameterFilter, final MethodHandle returnFilter) { |
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125 this.parameterFilter = checkHandle(parameterFilter, "parameterFilter"); |
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126 this.returnFilter = checkHandle(returnFilter, "returnFilter"); |
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127 this.varArgFilter = parameterFilter == null ? null : FILTER_VARARGS.bindTo(parameterFilter); |
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128 } |
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129 |
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130 @Override |
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131 public MethodHandle transform(final MethodHandle target) { |
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132 assert target != null; |
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133 MethodHandle[] filters = null; |
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134 final MethodType type = target.type(); |
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135 final boolean isVarArg = target.isVarargsCollector(); |
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136 final int paramCount = type.parameterCount(); |
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137 final MethodHandle paramsFiltered; |
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138 // Filter parameters |
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139 if (parameterFilter != null) { |
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140 int firstFilter = -1; |
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141 // Ignore receiver, start from argument 1 |
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142 for(int i = 1; i < paramCount; ++i) { |
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143 final Class<?> paramType = type.parameterType(i); |
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144 final boolean filterVarArg = isVarArg && i == paramCount - 1 && paramType == Object[].class; |
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145 if (filterVarArg || paramType == Object.class) { |
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146 if (filters == null) { |
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147 firstFilter = i; |
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148 filters = new MethodHandle[paramCount - firstFilter]; |
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149 } |
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150 filters[i - firstFilter] = filterVarArg ? varArgFilter : parameterFilter; |
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151 } |
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152 } |
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153 paramsFiltered = filters != null ? MethodHandles.filterArguments(target, firstFilter, filters) : target; |
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154 } else { |
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155 paramsFiltered = target; |
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156 } |
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157 // Filter return value if needed |
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158 final MethodHandle returnFiltered = returnFilter != null && type.returnType() == Object.class ? MethodHandles.filterReturnValue(paramsFiltered, returnFilter) : paramsFiltered; |
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159 // Preserve varargs collector state |
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160 return isVarArg && !returnFiltered.isVarargsCollector() ? returnFiltered.asVarargsCollector(type.parameterType(paramCount - 1)) : returnFiltered; |
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161 |
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162 } |
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163 |
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164 private static MethodHandle checkHandle(final MethodHandle handle, final String handleKind) { |
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165 if (handle != null) { |
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166 final MethodType objectObjectType = MethodType.methodType(Object.class, Object.class); |
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167 if (!handle.type().equals(objectObjectType)) { |
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168 throw new IllegalArgumentException("Method type for " + handleKind + " must be " + objectObjectType); |
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169 } |
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170 } |
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171 return handle; |
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172 } |
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173 |
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174 @SuppressWarnings("unused") |
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175 private static Object[] filterVarArgs(final MethodHandle parameterFilter, final Object[] args) throws Throwable { |
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176 Object[] newArgs = null; |
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177 for(int i = 0; i < args.length; ++i) { |
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178 final Object arg = args[i]; |
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179 final Object newArg = parameterFilter.invokeExact(arg); |
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180 if (arg != newArg) { |
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181 if (newArgs == null) { |
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182 newArgs = args.clone(); |
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183 } |
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184 newArgs[i] = newArg; |
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185 } |
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186 } |
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187 return newArgs == null ? args : newArgs; |
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188 } |
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189 } |