/*
 * This file is part of Araknemu.
 *
 * Araknemu is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * Araknemu 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 Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with Araknemu.  If not, see <https://www.gnu.org/licenses/>.
 *
 * Copyright (c) 2017-2019 Vincent Quatrevieux
 */

package fr.quatrevieux.araknemu.data.living.constraint;

import org.checkerframework.checker.nullness.qual.EnsuresNonNullIf;
import org.checkerframework.checker.nullness.qual.Nullable;

/**
 * Constraint for an entity
 *
 * EntityConstraint<> constraint = new ...;
 *
 * if (!constraint.value(entity)) {
 *     throw new MyError(constraint.error());
 * }
 *
 * @param <T> The entity type
 * @param <E> The error type
 */
public interface EntityConstraint<T, E> {
    /**
     * Check the entity
     *
     * @param entity entity to value
     *
     * @return true is the entity is valid
     */
    @EnsuresNonNullIf(expression = "error()", result = false)
    public boolean check(T entity);

    /**
     * Get the error information
     */
    public @Nullable E error();
}