Storable.java

/*
 * Copyright (c) 2015 NOVA, All rights reserved.
 * This library is free software, licensed under GNU Lesser General Public License version 3
 *
 * This file is part of NOVA.
 *
 * NOVA 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.
 *
 * NOVA 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 NOVA.  If not, see <http://www.gnu.org/licenses/>.
 */

package nova.core.retention;

import nova.core.util.ReflectionUtil;

import java.math.BigDecimal;
import java.math.BigInteger;
import java.util.Collection;
import java.util.List;
import java.util.Objects;

/**
 * Classes with this interface declare ability to store and load itself.
 * Therefore, classes using this interface must have an empty constructor for new instantiation from load.
 */
public interface Storable {

	/**
	 * Saves all the data of this object.
	 * See {@link Data} for what data is storable.
	 *
	 * The default implementation saves all fields tagged with {@link Store @Store}.
	 *
	 * @param data The data object to put values in.
	 */
	default void save(Data data) {
		ReflectionUtil.forEachRecursiveAnnotatedField(Store.class, getClass(), (field, annotation) -> {
			try {
				field.setAccessible(true);
				String name = annotation.key();
				if (name.isEmpty()) {
					name = field.getName();
					assert !Data.ILLEGAL_SUFFIX.matcher(name).find();
				}
				data.put(name, field.get(this));
				field.setAccessible(false);
			} catch (Exception e) {
				e.printStackTrace();
			}
		});
	}

	/**
	 * Loads all the data for this object.
	 * See {@link Data} for what data is storable.
	 *
	 * The default implementation loads all fields tagged with {@link Store @Store}.
	 *
	 * @param data The data object to load values from.
	 */
	default void load(Data data) {
		ReflectionUtil.forEachRecursiveAnnotatedField(Store.class, getClass(), (field, annotation) -> {
			String name = annotation.key();
			if (name.isEmpty()) {
				name = field.getName();
				assert !Data.ILLEGAL_SUFFIX.matcher(name).find();
			}
			if (data.containsKey(name)) {
				try {
					field.setAccessible(true);
					Class<?> type = field.getType();
					Object fieldValue = field.get(this);
					Object value = data.get(name);
					if (Storable.class.isAssignableFrom(type) || value instanceof Data) {
						if (fieldValue instanceof Storable && value instanceof Data) {
							//We already have an instance. Don't need to create the object.
							((Storable) fieldValue).load((Data) value);
						} else if (Collection.class.isAssignableFrom(type)) {
							if (List.class.isAssignableFrom(type)) {
								field.set(this, Data.unserialize((Data) value));
							} else {
								Collection<?> collection = (Collection) type.newInstance();
								field.set(this, collection.addAll(Data.unserialize((Data) value)));
							}
						} else {
							field.set(this, Data.unserialize((Data) value));
						}
					} else if (BigInteger.class.isAssignableFrom(type)) {
						if (value instanceof BigInteger)
							field.set(this, value);
						else
							field.set(this, new BigInteger(Objects.toString(value)));
					} else if (BigDecimal.class.isAssignableFrom(type)) {
						if (value instanceof BigDecimal)
							field.set(this, value);
						else
							field.set(this, new BigDecimal(Objects.toString(value)));
					} else if (value instanceof BigInteger) {
						if (int.class.isAssignableFrom(type) || Integer.class.isAssignableFrom(type))
							field.set(this, ((BigInteger) value).intValue());
						else
							field.set(this, ((BigInteger) value).longValue());
					} else if (value instanceof BigDecimal) {
						field.set(this, ((BigDecimal) value).doubleValue());
					} else {
						field.set(this, value);
					}
					field.setAccessible(false);
				} catch (Exception e) {
					e.printStackTrace();
				}
			}
		});
	}
}