com.squareup.moshi.MapJsonAdapter Maven / Gradle / Ivy

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/*
 * Copyright (C) 2015 Square, 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.squareup.moshi;

import com.jn.langx.annotation.Nullable;

import java.io.IOException;
import java.lang.annotation.Annotation;
import java.lang.reflect.Type;
import java.util.Map;
import java.util.Set;

/**
 * Converts maps with string keys to JSON objects.
 * 
 */
final class MapJsonAdapter extends JsonAdapter> {
    public static final Factory FACTORY = new Factory() {
        @Override
        public @Nullable
        JsonAdapter create(
                Type type, Set annotations, Moshi moshi) {
            if (!annotations.isEmpty()) {
                return null;
            }
            Class rawType = Types.getRawType(type);
            if (rawType != Map.class) {
                return null;
            }
            Type[] keyAndValue = Types.mapKeyAndValueTypes(type, rawType);
            return new MapJsonAdapter(moshi, keyAndValue[0], keyAndValue[1]).nullSafe();
        }
    };

    private final JsonAdapter keyAdapter;
    private final JsonAdapter valueAdapter;

    MapJsonAdapter(Moshi moshi, Type keyType, Type valueType) {
        this.keyAdapter = moshi.adapter(keyType);
        this.valueAdapter = moshi.adapter(valueType);
    }

    @Override
    public void toJson(JsonWriter writer, Map map) throws IOException {
        writer.beginObject();
        for (Map.Entry entry : map.entrySet()) {
            if (entry.getKey() == null) {
                throw new JsonDataException("Map key is null at " + writer.getPath());
            }
            writer.promoteValueToName();
            keyAdapter.toJson(writer, entry.getKey());
            valueAdapter.toJson(writer, entry.getValue());
        }
        writer.endObject();
    }

    @Override
    public Map fromJson(JsonReader reader) throws IOException {
        LinkedHashTreeMap result = new LinkedHashTreeMap();
        reader.beginObject();
        while (reader.hasNext()) {
            reader.promoteNameToValue();
            K name = keyAdapter.fromJson(reader);
            V value = valueAdapter.fromJson(reader);
            V replaced = result.put(name, value);
            if (replaced != null) {
                throw new JsonDataException("Map key '" + name + "' has multiple values at path "
                        + reader.getPath() + ": " + replaced + " and " + value);
            }
        }
        reader.endObject();
        return result;
    }

    @Override
    public String toString() {
        return "JsonAdapter(" + keyAdapter + "=" + valueAdapter + ")";
    }
}