| 1 | /* |
| 2 | * Copyright (C) 2009 Google Inc. |
| 3 | * |
| 4 | * Licensed under the Apache License, Version 2.0 (the "License"); |
| 5 | * you may not use this file except in compliance with the License. |
| 6 | * You may obtain a copy of the License at |
| 7 | * |
| 8 | * http://www.apache.org/licenses/LICENSE-2.0 |
| 9 | * |
| 10 | * Unless required by applicable law or agreed to in writing, software |
| 11 | * distributed under the License is distributed on an "AS IS" BASIS, |
| 12 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 13 | * See the License for the specific language governing permissions and |
| 14 | * limitations under the License. |
| 15 | */ |
| 16 | |
| 17 | package com.google.gson; |
| 18 | |
| 19 | import com.google.gson.internal.$Gson$Preconditions; |
| 20 | import java.lang.annotation.Annotation; |
| 21 | import java.lang.reflect.Field; |
| 22 | import java.lang.reflect.Type; |
| 23 | import java.util.Arrays; |
| 24 | import java.util.Collection; |
| 25 | |
| 26 | /** |
| 27 | * A data object that stores attributes of a field. |
| 28 | * |
| 29 | * <p>This class is immutable; therefore, it can be safely shared across threads. |
| 30 | * |
| 31 | * @author Inderjeet Singh |
| 32 | * @author Joel Leitch |
| 33 | * |
| 34 | * @since 1.4 |
| 35 | */ |
| 36 | public final class FieldAttributes { |
| 37 | private final Field field; |
| 38 | |
| 39 | /** |
| 40 | * Constructs a Field Attributes object from the {@code f}. |
| 41 | * |
| 42 | * @param f the field to pull attributes from |
| 43 | */ |
| 44 | public FieldAttributes(Field f) { |
| 45 | $Gson$Preconditions.checkNotNull(f); |
| 46 | this.field = f; |
| 47 | } |
| 48 | |
| 49 | /** |
| 50 | * @return the declaring class that contains this field |
| 51 | */ |
| 52 | public Class<?> getDeclaringClass() { |
| 53 | return field.getDeclaringClass(); |
| 54 | } |
| 55 | |
| 56 | /** |
| 57 | * @return the name of the field |
| 58 | */ |
| 59 | public String getName() { |
| 60 | return field.getName(); |
| 61 | } |
| 62 | |
| 63 | /** |
| 64 | * <p>For example, assume the following class definition: |
| 65 | * <pre class="code"> |
| 66 | * public class Foo { |
| 67 | * private String bar; |
| 68 | * private List<String> red; |
| 69 | * } |
| 70 | * |
| 71 | * Type listParmeterizedType = new TypeToken<List<String>>() {}.getType(); |
| 72 | * </pre> |
| 73 | * |
| 74 | * <p>This method would return {@code String.class} for the {@code bar} field and |
| 75 | * {@code listParameterizedType} for the {@code red} field. |
| 76 | * |
| 77 | * @return the specific type declared for this field |
| 78 | */ |
| 79 | public Type getDeclaredType() { |
| 80 | return field.getGenericType(); |
| 81 | } |
| 82 | |
| 83 | /** |
| 84 | * Returns the {@code Class} object that was declared for this field. |
| 85 | * |
| 86 | * <p>For example, assume the following class definition: |
| 87 | * <pre class="code"> |
| 88 | * public class Foo { |
| 89 | * private String bar; |
| 90 | * private List<String> red; |
| 91 | * } |
| 92 | * </pre> |
| 93 | * |
| 94 | * <p>This method would return {@code String.class} for the {@code bar} field and |
| 95 | * {@code List.class} for the {@code red} field. |
| 96 | * |
| 97 | * @return the specific class object that was declared for the field |
| 98 | */ |
| 99 | public Class<?> getDeclaredClass() { |
| 100 | return field.getType(); |
| 101 | } |
| 102 | |
| 103 | /** |
| 104 | * Return the {@code T} annotation object from this field if it exist; otherwise returns |
| 105 | * {@code null}. |
| 106 | * |
| 107 | * @param annotation the class of the annotation that will be retrieved |
| 108 | * @return the annotation instance if it is bound to the field; otherwise {@code null} |
| 109 | */ |
| 110 | public <T extends Annotation> T getAnnotation(Class<T> annotation) { |
| 111 | return field.getAnnotation(annotation); |
| 112 | } |
| 113 | |
| 114 | /** |
| 115 | * Return the annotations that are present on this field. |
| 116 | * |
| 117 | * @return an array of all the annotations set on the field |
| 118 | * @since 1.4 |
| 119 | */ |
| 120 | public Collection<Annotation> getAnnotations() { |
| 121 | return Arrays.asList(field.getAnnotations()); |
| 122 | } |
| 123 | |
| 124 | /** |
| 125 | * Returns {@code true} if the field is defined with the {@code modifier}. |
| 126 | * |
| 127 | * <p>This method is meant to be called as: |
| 128 | * <pre class="code"> |
| 129 | * boolean hasPublicModifier = fieldAttribute.hasModifier(java.lang.reflect.Modifier.PUBLIC); |
| 130 | * </pre> |
| 131 | * |
| 132 | * @see java.lang.reflect.Modifier |
| 133 | */ |
| 134 | public boolean hasModifier(int modifier) { |
| 135 | return (field.getModifiers() & modifier) != 0; |
| 136 | } |
| 137 | |
| 138 | /** |
| 139 | * This is exposed internally only for the removing synthetic fields from the JSON output. |
| 140 | * |
| 141 | * @return true if the field is synthetic; otherwise false |
| 142 | * @throws IllegalAccessException |
| 143 | * @throws IllegalArgumentException |
| 144 | */ |
| 145 | Object get(Object instance) throws IllegalAccessException { |
| 146 | return field.get(instance); |
| 147 | } |
| 148 | |
| 149 | /** |
| 150 | * This is exposed internally only for the removing synthetic fields from the JSON output. |
| 151 | * |
| 152 | * @return true if the field is synthetic; otherwise false |
| 153 | */ |
| 154 | boolean isSynthetic() { |
| 155 | return field.isSynthetic(); |
| 156 | } |
| 157 | } |