PlotSquared/Core/src/main/java/com/plotsquared/core/configuration/file/YamlConstructor.java

/*
 * PlotSquared, a land and world management plugin for Minecraft.
 * Copyright (C) IntellectualSites <https://intellectualsites.com>
 * Copyright (C) IntellectualSites team and contributors
 *
 * 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 <https://www.gnu.org/licenses/>.
 */
package com.plotsquared.core.configuration.file;

import com.plotsquared.core.configuration.serialization.ConfigurationSerialization;
import org.yaml.snakeyaml.LoaderOptions;
import org.yaml.snakeyaml.constructor.SafeConstructor;
import org.yaml.snakeyaml.error.YAMLException;
import org.yaml.snakeyaml.nodes.Node;
import org.yaml.snakeyaml.nodes.Tag;

import java.util.LinkedHashMap;
import java.util.Map;

public class YamlConstructor extends SafeConstructor {

    YamlConstructor() {
        super(new LoaderOptions());
        yamlConstructors.put(Tag.MAP, new ConstructCustomObject());
    }

    private class ConstructCustomObject extends ConstructYamlMap {

        @Override
        public Object construct(final Node node) {
            if (node.isTwoStepsConstruction()) {
                throw new YAMLException("Unexpected referential mapping structure. Node: " + node);
            }

            final Map<?, ?> raw = (Map<?, ?>) super.construct(node);

            if (raw.containsKey(ConfigurationSerialization.SERIALIZED_TYPE_KEY)) {
                final Map<String, Object> typed = new LinkedHashMap<>(raw.size());
                for (final Map.Entry<?, ?> entry : raw.entrySet()) {
                    typed.put(entry.getKey().toString(), entry.getValue());
                }

                try {
                    return ConfigurationSerialization.deserializeObject(typed);
                } catch (final IllegalArgumentException ex) {
                    throw new YAMLException("Could not deserialize object", ex);
                }
            }

            return raw;
        }

        @Override
        public void construct2ndStep(final Node node, final Object object) {
            throw new YAMLException("Unexpected referential mapping structure. Node: " + node);
        }

    }

}