| /* |
| * 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.ToNumberPolicy; |
| import com.google.gson.ToNumberStrategy; |
| import com.google.gson.TypeAdapter; |
| import com.google.gson.TypeAdapterFactory; |
| import com.google.gson.internal.LinkedTreeMap; |
| 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.util.ArrayDeque; |
| import java.util.ArrayList; |
| import java.util.Deque; |
| import java.util.List; |
| import java.util.Map; |
| |
| /** |
| * Adapts types whose static type is only 'Object'. Uses getClass() on |
| * serialization and a primitive/Map/List on deserialization. |
| */ |
| public final class ObjectTypeAdapter extends TypeAdapter<Object> { |
| /** |
| * Gson default factory using {@link ToNumberPolicy#DOUBLE}. |
| */ |
| private static final TypeAdapterFactory DOUBLE_FACTORY = newFactory(ToNumberPolicy.DOUBLE); |
| |
| private final Gson gson; |
| private final ToNumberStrategy toNumberStrategy; |
| |
| private ObjectTypeAdapter(Gson gson, ToNumberStrategy toNumberStrategy) { |
| this.gson = gson; |
| this.toNumberStrategy = toNumberStrategy; |
| } |
| |
| private static TypeAdapterFactory newFactory(final ToNumberStrategy toNumberStrategy) { |
| return new TypeAdapterFactory() { |
| @SuppressWarnings("unchecked") |
| @Override public <T> TypeAdapter<T> create(Gson gson, TypeToken<T> type) { |
| if (type.getRawType() == Object.class) { |
| return (TypeAdapter<T>) new ObjectTypeAdapter(gson, toNumberStrategy); |
| } |
| return null; |
| } |
| }; |
| } |
| |
| public static TypeAdapterFactory getFactory(ToNumberStrategy toNumberStrategy) { |
| if (toNumberStrategy == ToNumberPolicy.DOUBLE) { |
| return DOUBLE_FACTORY; |
| } else { |
| return newFactory(toNumberStrategy); |
| } |
| } |
| |
| /** |
| * Tries to begin reading a JSON array or JSON object, returning {@code null} if |
| * the next element is neither of those. |
| */ |
| private Object tryBeginNesting(JsonReader in, JsonToken peeked) throws IOException { |
| switch (peeked) { |
| case BEGIN_ARRAY: |
| in.beginArray(); |
| return new ArrayList<>(); |
| case BEGIN_OBJECT: |
| in.beginObject(); |
| return new LinkedTreeMap<>(); |
| default: |
| return null; |
| } |
| } |
| |
| /** Reads an {@code Object} which cannot have any nested elements */ |
| private Object readTerminal(JsonReader in, JsonToken peeked) throws IOException { |
| switch (peeked) { |
| case STRING: |
| return in.nextString(); |
| case NUMBER: |
| return toNumberStrategy.readNumber(in); |
| case BOOLEAN: |
| return in.nextBoolean(); |
| case NULL: |
| in.nextNull(); |
| return null; |
| default: |
| // When read(JsonReader) is called with JsonReader in invalid state |
| throw new IllegalStateException("Unexpected token: " + peeked); |
| } |
| } |
| |
| @Override public Object read(JsonReader in) throws IOException { |
| // Either List or Map |
| Object current; |
| JsonToken peeked = in.peek(); |
| |
| current = tryBeginNesting(in, peeked); |
| if (current == null) { |
| return readTerminal(in, peeked); |
| } |
| |
| Deque<Object> stack = new ArrayDeque<>(); |
| |
| while (true) { |
| while (in.hasNext()) { |
| String name = null; |
| // Name is only used for JSON object members |
| if (current instanceof Map) { |
| name = in.nextName(); |
| } |
| |
| peeked = in.peek(); |
| Object value = tryBeginNesting(in, peeked); |
| boolean isNesting = value != null; |
| |
| if (value == null) { |
| value = readTerminal(in, peeked); |
| } |
| |
| if (current instanceof List) { |
| @SuppressWarnings("unchecked") |
| List<Object> list = (List<Object>) current; |
| list.add(value); |
| } else { |
| @SuppressWarnings("unchecked") |
| Map<String, Object> map = (Map<String, Object>) current; |
| map.put(name, value); |
| } |
| |
| if (isNesting) { |
| stack.addLast(current); |
| current = value; |
| } |
| } |
| |
| // End current element |
| if (current instanceof List) { |
| in.endArray(); |
| } else { |
| in.endObject(); |
| } |
| |
| if (stack.isEmpty()) { |
| return current; |
| } else { |
| // Continue with enclosing element |
| current = stack.removeLast(); |
| } |
| } |
| } |
| |
| @SuppressWarnings("unchecked") |
| @Override public void write(JsonWriter out, Object value) throws IOException { |
| if (value == null) { |
| out.nullValue(); |
| return; |
| } |
| |
| TypeAdapter<Object> typeAdapter = (TypeAdapter<Object>) gson.getAdapter(value.getClass()); |
| if (typeAdapter instanceof ObjectTypeAdapter) { |
| out.beginObject(); |
| out.endObject(); |
| return; |
| } |
| |
| typeAdapter.write(out, value); |
| } |
| } |