X-Git-Url: http://git.ieval.ro/?a=blobdiff_plain;f=src%2Fcom%2Fgoogle%2Fgson%2Finternal%2Fbind%2FMapTypeAdapterFactory.java;fp=src%2Fcom%2Fgoogle%2Fgson%2Finternal%2Fbind%2FMapTypeAdapterFactory.java;h=c3c616c4eb42923c980058e6a1289b9daa7177c1;hb=cfd903b6b5113fa28991db19bf98d0340ae709a4;hp=0000000000000000000000000000000000000000;hpb=819197b2305a94ab4924c5ae37a3fad762078448;p=unical.git

diff --git a/src/com/google/gson/internal/bind/MapTypeAdapterFactory.java b/src/com/google/gson/internal/bind/MapTypeAdapterFactory.java
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+/*
+ * Copyright (C) 2011 Google Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.google.gson.internal.bind;
+
+import com.google.gson.Gson;
+import com.google.gson.JsonElement;
+import com.google.gson.JsonPrimitive;
+import com.google.gson.JsonSyntaxException;
+import com.google.gson.TypeAdapter;
+import com.google.gson.TypeAdapterFactory;
+import com.google.gson.internal.$Gson$Types;
+import com.google.gson.internal.ConstructorConstructor;
+import com.google.gson.internal.JsonReaderInternalAccess;
+import com.google.gson.internal.ObjectConstructor;
+import com.google.gson.internal.Streams;
+import com.google.gson.reflect.TypeToken;
+import com.google.gson.stream.JsonReader;
+import com.google.gson.stream.JsonToken;
+import com.google.gson.stream.JsonWriter;
+import java.io.IOException;
+import java.lang.reflect.Type;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Map;
+
+/**
+ * Adapts maps to either JSON objects or JSON arrays.
+ *
+ * <h3>Maps as JSON objects</h3>
+ * For primitive keys or when complex map key serialization is not enabled, this
+ * converts Java {@link Map Maps} to JSON Objects. This requires that map keys
+ * can be serialized as strings; this is insufficient for some key types. For
+ * example, consider a map whose keys are points on a grid. The default JSON
+ * form encodes reasonably: <pre>   {@code
+ *   Map<Point, String> original = new LinkedHashMap<Point, String>();
+ *   original.put(new Point(5, 6), "a");
+ *   original.put(new Point(8, 8), "b");
+ *   System.out.println(gson.toJson(original, type));
+ * }</pre>
+ * The above code prints this JSON object:<pre>   {@code
+ *   {
+ *     "(5,6)": "a",
+ *     "(8,8)": "b"
+ *   }
+ * }</pre>
+ * But GSON is unable to deserialize this value because the JSON string name is
+ * just the {@link Object#toString() toString()} of the map key. Attempting to
+ * convert the above JSON to an object fails with a parse exception:
+ * <pre>com.google.gson.JsonParseException: Expecting object found: "(5,6)"
+ *   at com.google.gson.JsonObjectDeserializationVisitor.visitFieldUsingCustomHandler
+ *   at com.google.gson.ObjectNavigator.navigateClassFields
+ *   ...</pre>
+ *
+ * <h3>Maps as JSON arrays</h3>
+ * An alternative approach taken by this type adapter when it is required and
+ * complex map key serialization is enabled is to encode maps as arrays of map
+ * entries. Each map entry is a two element array containing a key and a value.
+ * This approach is more flexible because any type can be used as the map's key;
+ * not just strings. But it's also less portable because the receiver of such
+ * JSON must be aware of the map entry convention.
+ *
+ * <p>Register this adapter when you are creating your GSON instance.
+ * <pre>   {@code
+ *   Gson gson = new GsonBuilder()
+ *     .registerTypeAdapter(Map.class, new MapAsArrayTypeAdapter())
+ *     .create();
+ * }</pre>
+ * This will change the structure of the JSON emitted by the code above. Now we
+ * get an array. In this case the arrays elements are map entries:
+ * <pre>   {@code
+ *   [
+ *     [
+ *       {
+ *         "x": 5,
+ *         "y": 6
+ *       },
+ *       "a",
+ *     ],
+ *     [
+ *       {
+ *         "x": 8,
+ *         "y": 8
+ *       },
+ *       "b"
+ *     ]
+ *   ]
+ * }</pre>
+ * This format will serialize and deserialize just fine as long as this adapter
+ * is registered.
+ */
+public final class MapTypeAdapterFactory implements TypeAdapterFactory {
+  private final ConstructorConstructor constructorConstructor;
+  private final boolean complexMapKeySerialization;
+
+  public MapTypeAdapterFactory(ConstructorConstructor constructorConstructor,
+      boolean complexMapKeySerialization) {
+    this.constructorConstructor = constructorConstructor;
+    this.complexMapKeySerialization = complexMapKeySerialization;
+  }
+
+  public <T> TypeAdapter<T> create(Gson gson, TypeToken<T> typeToken) {
+    Type type = typeToken.getType();
+
+    Class<? super T> rawType = typeToken.getRawType();
+    if (!Map.class.isAssignableFrom(rawType)) {
+      return null;
+    }
+
+    Class<?> rawTypeOfSrc = $Gson$Types.getRawType(type);
+    Type[] keyAndValueTypes = $Gson$Types.getMapKeyAndValueTypes(type, rawTypeOfSrc);
+    TypeAdapter<?> keyAdapter = getKeyAdapter(gson, keyAndValueTypes[0]);
+    TypeAdapter<?> valueAdapter = gson.getAdapter(TypeToken.get(keyAndValueTypes[1]));
+    ObjectConstructor<T> constructor = constructorConstructor.get(typeToken);
+
+    @SuppressWarnings({"unchecked", "rawtypes"})
+    // we don't define a type parameter for the key or value types
+    TypeAdapter<T> result = new Adapter(gson, keyAndValueTypes[0], keyAdapter,
+        keyAndValueTypes[1], valueAdapter, constructor);
+    return result;
+  }
+
+  /**
+   * Returns a type adapter that writes the value as a string.
+   */
+  private TypeAdapter<?> getKeyAdapter(Gson context, Type keyType) {
+    return (keyType == boolean.class || keyType == Boolean.class)
+        ? TypeAdapters.BOOLEAN_AS_STRING
+        : context.getAdapter(TypeToken.get(keyType));
+  }
+
+  private final class Adapter<K, V> extends TypeAdapter<Map<K, V>> {
+    private final TypeAdapter<K> keyTypeAdapter;
+    private final TypeAdapter<V> valueTypeAdapter;
+    private final ObjectConstructor<? extends Map<K, V>> constructor;
+
+    public Adapter(Gson context, Type keyType, TypeAdapter<K> keyTypeAdapter,
+        Type valueType, TypeAdapter<V> valueTypeAdapter,
+        ObjectConstructor<? extends Map<K, V>> constructor) {
+      this.keyTypeAdapter =
+        new TypeAdapterRuntimeTypeWrapper<K>(context, keyTypeAdapter, keyType);
+      this.valueTypeAdapter =
+        new TypeAdapterRuntimeTypeWrapper<V>(context, valueTypeAdapter, valueType);
+      this.constructor = constructor;
+    }
+
+    public Map<K, V> read(JsonReader in) throws IOException {
+      JsonToken peek = in.peek();
+      if (peek == JsonToken.NULL) {
+        in.nextNull();
+        return null;
+      }
+
+      Map<K, V> map = constructor.construct();
+
+      if (peek == JsonToken.BEGIN_ARRAY) {
+        in.beginArray();
+        while (in.hasNext()) {
+          in.beginArray(); // entry array
+          K key = keyTypeAdapter.read(in);
+          V value = valueTypeAdapter.read(in);
+          V replaced = map.put(key, value);
+          if (replaced != null) {
+            throw new JsonSyntaxException("duplicate key: " + key);
+          }
+          in.endArray();
+        }
+        in.endArray();
+      } else {
+        in.beginObject();
+        while (in.hasNext()) {
+          JsonReaderInternalAccess.INSTANCE.promoteNameToValue(in);
+          K key = keyTypeAdapter.read(in);
+          V value = valueTypeAdapter.read(in);
+          V replaced = map.put(key, value);
+          if (replaced != null) {
+            throw new JsonSyntaxException("duplicate key: " + key);
+          }
+        }
+        in.endObject();
+      }
+      return map;
+    }
+
+    public void write(JsonWriter out, Map<K, V> map) throws IOException {
+      if (map == null) {
+        out.nullValue();
+        return;
+      }
+
+      if (!complexMapKeySerialization) {
+        out.beginObject();
+        for (Map.Entry<K, V> entry : map.entrySet()) {
+          out.name(String.valueOf(entry.getKey()));
+          valueTypeAdapter.write(out, entry.getValue());
+        }
+        out.endObject();
+        return;
+      }
+
+      boolean hasComplexKeys = false;
+      List<JsonElement> keys = new ArrayList<JsonElement>(map.size());
+
+      List<V> values = new ArrayList<V>(map.size());
+      for (Map.Entry<K, V> entry : map.entrySet()) {
+        JsonElement keyElement = keyTypeAdapter.toJsonTree(entry.getKey());
+        keys.add(keyElement);
+        values.add(entry.getValue());
+        hasComplexKeys |= keyElement.isJsonArray() || keyElement.isJsonObject();
+      }
+
+      if (hasComplexKeys) {
+        out.beginArray();
+        for (int i = 0; i < keys.size(); i++) {
+          out.beginArray(); // entry array
+          Streams.write(keys.get(i), out);
+          valueTypeAdapter.write(out, values.get(i));
+          out.endArray();
+        }
+        out.endArray();
+      } else {
+        out.beginObject();
+        for (int i = 0; i < keys.size(); i++) {
+          JsonElement keyElement = keys.get(i);
+          out.name(keyToString(keyElement));
+          valueTypeAdapter.write(out, values.get(i));
+        }
+        out.endObject();
+      }
+    }
+
+    private String keyToString(JsonElement keyElement) {
+      if (keyElement.isJsonPrimitive()) {
+        JsonPrimitive primitive = keyElement.getAsJsonPrimitive();
+        if (primitive.isNumber()) {
+          return String.valueOf(primitive.getAsNumber());
+        } else if (primitive.isBoolean()) {
+          return Boolean.toString(primitive.getAsBoolean());
+        } else if (primitive.isString()) {
+          return primitive.getAsString();
+        } else {
+          throw new AssertionError();
+        }
+      } else if (keyElement.isJsonNull()) {
+        return "null";
+      } else {
+        throw new AssertionError();
+      }
+    }
+  }
+}