1 | // Protocol Buffers - Google's data interchange format |
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2 | // Copyright 2008 Google Inc. All rights reserved. |
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3 | // http://code.google.com/p/protobuf/ |
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4 | // |
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5 | // Redistribution and use in source and binary forms, with or without |
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6 | // modification, are permitted provided that the following conditions are |
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7 | // met: |
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8 | // |
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9 | // * Redistributions of source code must retain the above copyright |
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10 | // notice, this list of conditions and the following disclaimer. |
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11 | // * Redistributions in binary form must reproduce the above |
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12 | // copyright notice, this list of conditions and the following disclaimer |
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13 | // in the documentation and/or other materials provided with the |
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14 | // distribution. |
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15 | // * Neither the name of Google Inc. nor the names of its |
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16 | // contributors may be used to endorse or promote products derived from |
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17 | // this software without specific prior written permission. |
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18 | // |
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19 | // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
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20 | // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
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21 | // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR |
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22 | // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT |
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23 | // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, |
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24 | // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT |
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25 | // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
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26 | // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
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27 | // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
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28 | // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE |
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29 | // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
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30 | |
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31 | package com.google.protobuf; |
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32 | |
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33 | import java.util.Collections; |
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34 | import java.util.HashMap; |
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35 | import java.util.Map; |
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36 | |
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37 | /** |
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38 | * Equivalent to {@link ExtensionRegistry} but supports only "lite" types. |
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39 | * <p> |
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40 | * If all of your types are lite types, then you only need to use |
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41 | * {@code ExtensionRegistryLite}. Similarly, if all your types are regular |
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42 | * types, then you only need {@link ExtensionRegistry}. Typically it does not |
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43 | * make sense to mix the two, since if you have any regular types in your |
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44 | * program, you then require the full runtime and lose all the benefits of |
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45 | * the lite runtime, so you might as well make all your types be regular types. |
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46 | * However, in some cases (e.g. when depending on multiple third-patry libraries |
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47 | * where one uses lite types and one uses regular), you may find yourself |
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48 | * wanting to mix the two. In this case things get more complicated. |
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49 | * <p> |
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50 | * There are three factors to consider: Whether the type being extended is |
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51 | * lite, whether the embedded type (in the case of a message-typed extension) |
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52 | * is lite, and whether the extension itself is lite. Since all three are |
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53 | * declared in different files, they could all be different. Here are all |
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54 | * the combinations and which type of registry to use: |
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55 | * <pre> |
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56 | * Extended type Inner type Extension Use registry |
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57 | * ======================================================================= |
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58 | * lite lite lite ExtensionRegistryLite |
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59 | * lite regular lite ExtensionRegistry |
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60 | * regular regular regular ExtensionRegistry |
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61 | * all other combinations not supported |
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62 | * </pre> |
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63 | * <p> |
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64 | * Note that just as regular types are not allowed to contain lite-type fields, |
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65 | * they are also not allowed to contain lite-type extensions. This is because |
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66 | * regular types must be fully accessible via reflection, which in turn means |
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67 | * that all the inner messages must also support reflection. On the other hand, |
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68 | * since regular types implement the entire lite interface, there is no problem |
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69 | * with embedding regular types inside lite types. |
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70 | * |
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71 | * @author kenton@google.com Kenton Varda |
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72 | */ |
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73 | public class ExtensionRegistryLite { |
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74 | /** Construct a new, empty instance. */ |
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75 | public static ExtensionRegistryLite newInstance() { |
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76 | return new ExtensionRegistryLite(); |
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77 | } |
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78 | |
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79 | /** Get the unmodifiable singleton empty instance. */ |
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80 | public static ExtensionRegistryLite getEmptyRegistry() { |
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81 | return EMPTY; |
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82 | } |
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83 | |
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84 | /** Returns an unmodifiable view of the registry. */ |
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85 | public ExtensionRegistryLite getUnmodifiable() { |
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86 | return new ExtensionRegistryLite(this); |
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87 | } |
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88 | |
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89 | /** |
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90 | * Find an extension by containing type and field number. |
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91 | * |
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92 | * @return Information about the extension if found, or {@code null} |
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93 | * otherwise. |
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94 | */ |
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95 | @SuppressWarnings("unchecked") |
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96 | public <ContainingType extends MessageLite> |
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97 | GeneratedMessageLite.GeneratedExtension<ContainingType, ?> |
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98 | findLiteExtensionByNumber( |
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99 | final ContainingType containingTypeDefaultInstance, |
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100 | final int fieldNumber) { |
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101 | return (GeneratedMessageLite.GeneratedExtension<ContainingType, ?>) |
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102 | extensionsByNumber.get( |
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103 | new ObjectIntPair(containingTypeDefaultInstance, fieldNumber)); |
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104 | } |
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105 | |
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106 | /** Add an extension from a lite generated file to the registry. */ |
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107 | public final void add( |
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108 | final GeneratedMessageLite.GeneratedExtension<?, ?> extension) { |
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109 | extensionsByNumber.put( |
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110 | new ObjectIntPair(extension.getContainingTypeDefaultInstance(), |
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111 | extension.getNumber()), |
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112 | extension); |
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113 | } |
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114 | |
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115 | // ================================================================= |
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116 | // Private stuff. |
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117 | |
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118 | // Constructors are package-private so that ExtensionRegistry can subclass |
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119 | // this. |
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120 | |
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121 | ExtensionRegistryLite() { |
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122 | this.extensionsByNumber = |
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123 | new HashMap<ObjectIntPair, |
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124 | GeneratedMessageLite.GeneratedExtension<?, ?>>(); |
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125 | } |
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126 | |
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127 | ExtensionRegistryLite(ExtensionRegistryLite other) { |
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128 | if (other == EMPTY) { |
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129 | this.extensionsByNumber = Collections.emptyMap(); |
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130 | } else { |
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131 | this.extensionsByNumber = |
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132 | Collections.unmodifiableMap(other.extensionsByNumber); |
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133 | } |
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134 | } |
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135 | |
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136 | private final Map<ObjectIntPair, |
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137 | GeneratedMessageLite.GeneratedExtension<?, ?>> |
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138 | extensionsByNumber; |
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139 | |
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140 | private ExtensionRegistryLite(boolean empty) { |
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141 | this.extensionsByNumber = Collections.emptyMap(); |
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142 | } |
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143 | private static final ExtensionRegistryLite EMPTY = |
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144 | new ExtensionRegistryLite(true); |
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145 | |
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146 | /** A (Object, int) pair, used as a map key. */ |
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147 | private static final class ObjectIntPair { |
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148 | private final Object object; |
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149 | private final int number; |
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150 | |
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151 | ObjectIntPair(final Object object, final int number) { |
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152 | this.object = object; |
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153 | this.number = number; |
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154 | } |
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155 | |
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156 | @Override |
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157 | public int hashCode() { |
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158 | return System.identityHashCode(object) * ((1 << 16) - 1) + number; |
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159 | } |
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160 | @Override |
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161 | public boolean equals(final Object obj) { |
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162 | if (!(obj instanceof ObjectIntPair)) { |
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163 | return false; |
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164 | } |
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165 | final ObjectIntPair other = (ObjectIntPair)obj; |
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166 | return object == other.object && number == other.number; |
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167 | } |
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168 | } |
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169 | } |
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