praktikum-holons/src/holeg/serialize/ModelDeserializer.java

package holeg.serialize;

import com.google.gson.*;
import com.google.gson.reflect.TypeToken;
import holeg.model.*;
import holeg.ui.model.IdCounter;

import java.lang.reflect.Type;
import java.util.HashSet;
import java.util.function.Function;
import java.util.logging.Logger;
import java.util.stream.Collectors;

public class ModelDeserializer implements JsonDeserializer<Model>{
    public static final Gson gson = initGson();
    private static final Logger log = Logger.getLogger(ModelDeserializer.class.getName());
    private final static Type edgeSetType = TypeToken.getParameterized(HashSet.class, Edge.class).getType();
    private final EdgeDeserializer edgeDeserializer = new EdgeDeserializer();
    private final Gson edgeGson = new GsonBuilder().registerTypeAdapter(Edge.class, edgeDeserializer).create();
    private static Gson initGson() {
        GsonBuilder builder = new GsonBuilder();
        builder.registerTypeAdapter(Edge.class, new EdgeSerializer());
        builder.registerTypeAdapter(Model.class, new ModelDeserializer());
        builder.registerTypeAdapterFactory(new PostDeserializeEnabler());

        builder.serializeNulls();
        builder.setPrettyPrinting();
        return builder.create();
    }

    @Override
    public Model deserialize(JsonElement json, Type typeOfT, JsonDeserializationContext context) throws JsonParseException {
        JsonObject jsonObj = json.getAsJsonObject();

        Model model = new Model();
        GroupNode canvas = context.deserialize(jsonObj.getAsJsonObject("canvas"), GroupNode.class);
        model.setCanvas(canvas);
        edgeDeserializer.idMap = canvas.getAllObjectsRecursive()
                .collect(Collectors.toMap(AbstractCanvasObject::getId, Function.identity()));
        model.setEdgesOnCanvas(edgeGson.fromJson(jsonObj.getAsJsonArray("edgesOnCanvas"), edgeSetType));

        updateIdCounter(model.getCanvas());
        return model;
    }

    private void updateIdCounter(GroupNode canvas){
        canvas.getAllObjectsRecursive().mapToInt(AbstractCanvasObject::getId).max()
                .ifPresent(maxId -> IdCounter.set(maxId + 1));
    }
}