| 1 | /* |
| 2 | * Copyright (C) 2011 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.internal.bind; |
| 18 | |
| 19 | import com.google.gson.FieldNamingStrategy; |
| 20 | import com.google.gson.Gson; |
| 21 | import com.google.gson.JsonSyntaxException; |
| 22 | import com.google.gson.TypeAdapter; |
| 23 | import com.google.gson.TypeAdapterFactory; |
| 24 | import com.google.gson.annotations.SerializedName; |
| 25 | import com.google.gson.internal.$Gson$Types; |
| 26 | import com.google.gson.internal.ConstructorConstructor; |
| 27 | import com.google.gson.internal.Excluder; |
| 28 | import com.google.gson.internal.ObjectConstructor; |
| 29 | import com.google.gson.internal.Primitives; |
| 30 | import com.google.gson.reflect.TypeToken; |
| 31 | import com.google.gson.stream.JsonReader; |
| 32 | import com.google.gson.stream.JsonToken; |
| 33 | import com.google.gson.stream.JsonWriter; |
| 34 | import java.io.IOException; |
| 35 | import java.lang.reflect.Field; |
| 36 | import java.lang.reflect.Type; |
| 37 | import java.util.LinkedHashMap; |
| 38 | import java.util.Map; |
| 39 | |
| 40 | /** |
| 41 | * Type adapter that reflects over the fields and methods of a class. |
| 42 | */ |
| 43 | public final class ReflectiveTypeAdapterFactory implements TypeAdapterFactory { |
| 44 | private final ConstructorConstructor constructorConstructor; |
| 45 | private final FieldNamingStrategy fieldNamingPolicy; |
| 46 | private final Excluder excluder; |
| 47 | |
| 48 | public ReflectiveTypeAdapterFactory(ConstructorConstructor constructorConstructor, |
| 49 | FieldNamingStrategy fieldNamingPolicy, Excluder excluder) { |
| 50 | this.constructorConstructor = constructorConstructor; |
| 51 | this.fieldNamingPolicy = fieldNamingPolicy; |
| 52 | this.excluder = excluder; |
| 53 | } |
| 54 | |
| 55 | public boolean excludeField(Field f, boolean serialize) { |
| 56 | return !excluder.excludeClass(f.getType(), serialize) && !excluder.excludeField(f, serialize); |
| 57 | } |
| 58 | |
| 59 | private String getFieldName(Field f) { |
| 60 | SerializedName serializedName = f.getAnnotation(SerializedName.class); |
| 61 | return serializedName == null ? fieldNamingPolicy.translateName(f) : serializedName.value(); |
| 62 | } |
| 63 | |
| 64 | public <T> TypeAdapter<T> create(Gson gson, final TypeToken<T> type) { |
| 65 | Class<? super T> raw = type.getRawType(); |
| 66 | |
| 67 | if (!Object.class.isAssignableFrom(raw)) { |
| 68 | return null; // it's a primitive! |
| 69 | } |
| 70 | |
| 71 | ObjectConstructor<T> constructor = constructorConstructor.get(type); |
| 72 | return new Adapter<T>(constructor, getBoundFields(gson, type, raw)); |
| 73 | } |
| 74 | |
| 75 | private ReflectiveTypeAdapterFactory.BoundField createBoundField( |
| 76 | final Gson context, final Field field, final String name, |
| 77 | final TypeToken<?> fieldType, boolean serialize, boolean deserialize) { |
| 78 | final boolean isPrimitive = Primitives.isPrimitive(fieldType.getRawType()); |
| 79 | |
| 80 | // special casing primitives here saves ~5% on Android... |
| 81 | return new ReflectiveTypeAdapterFactory.BoundField(name, serialize, deserialize) { |
| 82 | final TypeAdapter<?> typeAdapter = context.getAdapter(fieldType); |
| 83 | @SuppressWarnings({"unchecked", "rawtypes"}) // the type adapter and field type always agree |
| 84 | @Override void write(JsonWriter writer, Object value) |
| 85 | throws IOException, IllegalAccessException { |
| 86 | Object fieldValue = field.get(value); |
| 87 | TypeAdapter t = |
| 88 | new TypeAdapterRuntimeTypeWrapper(context, this.typeAdapter, fieldType.getType()); |
| 89 | t.write(writer, fieldValue); |
| 90 | } |
| 91 | @Override void read(JsonReader reader, Object value) |
| 92 | throws IOException, IllegalAccessException { |
| 93 | Object fieldValue = typeAdapter.read(reader); |
| 94 | if (fieldValue != null || !isPrimitive) { |
| 95 | field.set(value, fieldValue); |
| 96 | } |
| 97 | } |
| 98 | }; |
| 99 | } |
| 100 | |
| 101 | private Map<String, BoundField> getBoundFields(Gson context, TypeToken<?> type, Class<?> raw) { |
| 102 | Map<String, BoundField> result = new LinkedHashMap<String, BoundField>(); |
| 103 | if (raw.isInterface()) { |
| 104 | return result; |
| 105 | } |
| 106 | |
| 107 | Type declaredType = type.getType(); |
| 108 | while (raw != Object.class) { |
| 109 | Field[] fields = raw.getDeclaredFields(); |
| 110 | for (Field field : fields) { |
| 111 | boolean serialize = excludeField(field, true); |
| 112 | boolean deserialize = excludeField(field, false); |
| 113 | if (!serialize && !deserialize) { |
| 114 | continue; |
| 115 | } |
| 116 | field.setAccessible(true); |
| 117 | Type fieldType = $Gson$Types.resolve(type.getType(), raw, field.getGenericType()); |
| 118 | BoundField boundField = createBoundField(context, field, getFieldName(field), |
| 119 | TypeToken.get(fieldType), serialize, deserialize); |
| 120 | BoundField previous = result.put(boundField.name, boundField); |
| 121 | if (previous != null) { |
| 122 | throw new IllegalArgumentException(declaredType |
| 123 | + " declares multiple JSON fields named " + previous.name); |
| 124 | } |
| 125 | } |
| 126 | type = TypeToken.get($Gson$Types.resolve(type.getType(), raw, raw.getGenericSuperclass())); |
| 127 | raw = type.getRawType(); |
| 128 | } |
| 129 | return result; |
| 130 | } |
| 131 | |
| 132 | static abstract class BoundField { |
| 133 | final String name; |
| 134 | final boolean serialized; |
| 135 | final boolean deserialized; |
| 136 | |
| 137 | protected BoundField(String name, boolean serialized, boolean deserialized) { |
| 138 | this.name = name; |
| 139 | this.serialized = serialized; |
| 140 | this.deserialized = deserialized; |
| 141 | } |
| 142 | |
| 143 | abstract void write(JsonWriter writer, Object value) throws IOException, IllegalAccessException; |
| 144 | abstract void read(JsonReader reader, Object value) throws IOException, IllegalAccessException; |
| 145 | } |
| 146 | |
| 147 | public static final class Adapter<T> extends TypeAdapter<T> { |
| 148 | private final ObjectConstructor<T> constructor; |
| 149 | private final Map<String, BoundField> boundFields; |
| 150 | |
| 151 | private Adapter(ObjectConstructor<T> constructor, Map<String, BoundField> boundFields) { |
| 152 | this.constructor = constructor; |
| 153 | this.boundFields = boundFields; |
| 154 | } |
| 155 | |
| 156 | @Override public T read(JsonReader in) throws IOException { |
| 157 | if (in.peek() == JsonToken.NULL) { |
| 158 | in.nextNull(); |
| 159 | return null; |
| 160 | } |
| 161 | |
| 162 | T instance = constructor.construct(); |
| 163 | |
| 164 | try { |
| 165 | in.beginObject(); |
| 166 | while (in.hasNext()) { |
| 167 | String name = in.nextName(); |
| 168 | BoundField field = boundFields.get(name); |
| 169 | if (field == null || !field.deserialized) { |
| 170 | in.skipValue(); |
| 171 | } else { |
| 172 | field.read(in, instance); |
| 173 | } |
| 174 | } |
| 175 | } catch (IllegalStateException e) { |
| 176 | throw new JsonSyntaxException(e); |
| 177 | } catch (IllegalAccessException e) { |
| 178 | throw new AssertionError(e); |
| 179 | } |
| 180 | in.endObject(); |
| 181 | return instance; |
| 182 | } |
| 183 | |
| 184 | @Override public void write(JsonWriter out, T value) throws IOException { |
| 185 | if (value == null) { |
| 186 | out.nullValue(); |
| 187 | return; |
| 188 | } |
| 189 | |
| 190 | out.beginObject(); |
| 191 | try { |
| 192 | for (BoundField boundField : boundFields.values()) { |
| 193 | if (boundField.serialized) { |
| 194 | out.name(boundField.name); |
| 195 | boundField.write(out, value); |
| 196 | } |
| 197 | } |
| 198 | } catch (IllegalAccessException e) { |
| 199 | throw new AssertionError(); |
| 200 | } |
| 201 | out.endObject(); |
| 202 | } |
| 203 | } |
| 204 | } |