1 /* |
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2 * Copyright (c) 2010, 2013, 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 2009-2013 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.internal.dynalink.linker; |
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85 |
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86 import java.lang.invoke.MethodHandle; |
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87 import java.lang.invoke.MethodType; |
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88 import java.util.List; |
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89 import jdk.internal.dynalink.DynamicLinkerFactory; |
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90 |
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91 /** |
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92 * The base interface for language-specific dynamic linkers. Such linkers |
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93 * always have to produce method handles with guards, as the validity of the |
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94 * method handle for calls at a call site inevitably depends on some condition |
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95 * (at the very least, it depends on the receiver belonging to the language |
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96 * runtime of the linker). Language runtime implementors will normally implement |
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97 * the linking logic for their own language as one or more |
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98 * {@link GuardingDynamicLinker} classes. They will typically set them as |
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99 * {@link DynamicLinkerFactory#setPrioritizedLinkers(List) prioritized linkers} |
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100 * in the {@code DynamicLinkerFactory} they configure for themselves, and maybe also |
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101 * set some as {@link DynamicLinkerFactory#setFallbackLinkers(List) fallback |
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102 * linkers} to handle language-specific "property not found" etc. conditions. |
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103 * <p> |
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104 * Consider implementing {@link TypeBasedGuardingDynamicLinker} interface |
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105 * instead of this interface for those linkers that are based on the Java class |
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106 * of the objects. If you need to implement language-specific type conversions, |
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107 * have your {@code GuardingDynamicLinker} also implement the |
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108 * {@link GuardingTypeConverterFactory} interface. |
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109 * <p> |
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110 * Languages can export linkers to other language runtimes for |
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111 * {@link DynamicLinkerFactory#setClassLoader(ClassLoader) automatic discovery} |
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112 * using a {@link GuardingDynamicLinkerExporter}. |
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113 */ |
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114 public interface GuardingDynamicLinker { |
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115 /** |
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116 * Creates a guarded invocation appropriate for a particular invocation with |
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117 * the specified arguments at a call site. |
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118 * |
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119 * @param linkRequest the object describing the request for linking a |
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120 * particular invocation |
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121 * @param linkerServices linker services |
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122 * @return a guarded invocation with a method handle suitable for the |
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123 * arguments, as well as a guard condition that if fails should trigger |
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124 * relinking. Must return null if it can't resolve the invocation. If the |
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125 * returned invocation is unconditional (which is actually quite rare), the |
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126 * guard in the return value can be null. The invocation can also have any |
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127 * number of switch points for asynchronous invalidation of the linkage, as |
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128 * well as a {@link Throwable} subclass that describes an expected exception |
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129 * condition that also triggers relinking (often it is faster to rely on an |
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130 * infrequent but expected {@link ClassCastException} than on an always |
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131 * evaluated {@code instanceof} guard). While the linker must produce an |
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132 * invocation with parameter types matching those in the call site |
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133 * descriptor of the link request, it should not try to match the return |
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134 * type expected at the call site except when it can do it with only the |
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135 * conversions that lose neither precision nor magnitude, see |
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136 * {@link LinkerServices#asTypeLosslessReturn(MethodHandle, MethodType)} for |
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137 * further explanation. |
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138 * @throws Exception if the operation fails for whatever reason |
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139 */ |
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140 public GuardedInvocation getGuardedInvocation(LinkRequest linkRequest, LinkerServices linkerServices) |
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141 throws Exception; |
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142 } |
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