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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 2009-2013 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 /** |
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85 * <p> |
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86 * Dynalink is a library for dynamic linking high-level operations on objects |
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87 * such as "read a property", "write a property", "invoke a function" and so on, |
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88 * expressed as {@link java.lang.invoke.CallSite call sites}. As such, it is |
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89 * closely related to, and relies on, the {@link java.lang.invoke} package. |
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90 * </p><p> |
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91 * While {@link java.lang.invoke} provides a JVM-level foundation for |
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92 * application-specific dynamic linking of methods, it does not provide a way to |
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93 * express higher level operations on objects, nor methods that implement them. |
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94 * These operations are the usual regimen of operations in object-oriented |
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95 * environments: property access, access of elements of collections, invocation |
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96 * of constructors, invocation of named methods (potentially with multiple |
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97 * dispatch, e.g. link- and run-time equivalents of Java overloaded method |
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98 * resolution). These are all functions that are normally desired in a language |
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99 * on the JVM. When a JVM language is statically typed and its type system |
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100 * matches that of the JVM, it can accomplish this with use of the usual |
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101 * invocation bytecodes ({@code INVOKEVIRTUAL} etc.) as well as field access |
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102 * bytecodes ({@code GETFIELD}, {@code PUTFIELD}). However, if the language is |
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103 * dynamic (hence, types of some expressions are not known at the time the |
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104 * program is compiled to bytecode), or its type system doesn't match closely |
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105 * that of the JVM, then it should use {@code invokedynamic} call sites and let |
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106 * Dynalink link those. |
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107 * </p><p> |
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108 * Dynalink lets programs have their operations on objects of unknown static |
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109 * types linked dynamically at run time. It also lets a language expose a linker |
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110 * for its own object model. Finally, it provides a default linker for ordinary |
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111 * Java objects. Two languages both exporting their linkers in the same JVM will |
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112 * even be able to cross-link their operations with each other if an object |
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113 * belonging to one language is passed to code from the other language. |
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114 * </p> |
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115 * <p> |
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116 * Languages that use Dynalink will create and configure a |
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117 * {@link jdk.internal.dynalink.DynamicLinkerFactory} and use it to create a |
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118 * {@link jdk.internal.dynalink.DynamicLinker}. |
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119 * The thus created dynamic linker will have to be used to link any |
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120 * {@link jdk.internal.dynalink.RelinkableCallSite}s they create, most often from a |
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121 * {@link java.lang.invoke} bootstrap method. |
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122 * </p> |
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123 * <p> |
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124 * Languages that wish to define and use their own linkers will also need to |
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125 * use the {@link jdk.internal.dynalink.linker} package. |
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126 * </p> |
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127 * @since 1.9 |
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128 */ |
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129 @jdk.Exported |
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130 package jdk.internal.dynalink; |