fr.ird.observe.gson.MultimapAdapterSupport Maven / Gradle / Ivy

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package fr.ird.observe.gson;

/*
 * #%L
 * ObServe Toolkit :: Dto
 * %%
 * Copyright (C) 2017 - 2021 Ultreia.io
 * %%
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as
 * published by the Free Software Foundation, either version 3 of the
 * License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public
 * License along with this program.  If not, see
 * .
 * #L%
 */

import com.google.common.collect.Multimap;
import com.google.common.reflect.TypeParameter;
import com.google.common.reflect.TypeToken;
import com.google.gson.JsonArray;
import com.google.gson.JsonDeserializationContext;
import com.google.gson.JsonDeserializer;
import com.google.gson.JsonElement;
import com.google.gson.JsonObject;
import com.google.gson.JsonParseException;
import com.google.gson.JsonSerializationContext;
import com.google.gson.JsonSerializer;

import java.lang.reflect.ParameterizedType;
import java.lang.reflect.Type;
import java.util.Collection;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.List;
import java.util.Map;

/**
 * @author Tony Chemit - [email protected]
 * @since 6.0
 */
public abstract class MultimapAdapterSupport implements JsonDeserializer, JsonSerializer {

    static  TypeToken>> multimapOf(TypeToken keyType, TypeToken valueType) {
        return new TypeToken>>() {
        }
                .where(new TypeParameter<>() {
                }, keyType)
                .where(new TypeParameter<>() {
                }, valueType);
    }

    protected abstract M createMultimap();

    @Override
    public M deserialize(JsonElement json, Type type, JsonDeserializationContext context) throws JsonParseException {

        Type[] actualTypeArguments = ((ParameterizedType) type).getActualTypeArguments();
        Type keyType = actualTypeArguments[0];
        Type valueType = actualTypeArguments[1];

        Type type2 = multimapOf(TypeToken.of(keyType), TypeToken.of(valueType)).getType();

        M result = createMultimap();
        if (!json.isJsonArray()) {

            Map map = context.deserialize(json, type2);

            for (Object key : map.keySet()) {
                List multimapValues = (List) map.get(key);
                result.putAll(key, multimapValues);
            }
        } else {
            JsonArray asJsonArray = json.getAsJsonArray();
            Iterator iterator = asJsonArray.iterator();
            while (iterator.hasNext()) {
                JsonObject entryObject = (JsonObject) iterator.next();
                Object key = context.deserialize(entryObject.get("key"), keyType);
                JsonArray valuesArray = (JsonArray) entryObject.get("value");
                Iterator valuesIterator = valuesArray.iterator();
                List entryValues = new LinkedList();
                while (valuesIterator.hasNext()) {
                    JsonElement value = valuesIterator.next();
                    entryValues.add(context.deserialize(value, valueType));
                }
                result.putAll(key, entryValues);
            }
        }
        return result;
    }

    @Override
    public JsonElement serialize(M src, Type type, JsonSerializationContext context) {
        Type[] actualTypeArguments = ((ParameterizedType) type).getActualTypeArguments();
        Type keyType = actualTypeArguments[0];
        Type valueType = actualTypeArguments[1];

        JsonArray result = new JsonArray();
        for (Object o : src.asMap().entrySet()) {
            Map.Entry entry = (Map.Entry) o;
            Object key = entry.getKey();
            Collection value = (Collection) entry.getValue();
            JsonObject entryObject = new JsonObject();
            entryObject.add("key", context.serialize(key));
            JsonArray valuesObject = new JsonArray();
            for (Object o1 : value) {
                valuesObject.add(context.serialize(o1, valueType));
            }
            entryObject.add("value", valuesObject);
            result.add(entryObject);
        }

        return result;
    }
}