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/*
 * Copyright © 2013-2024, The SeedStack authors 
 *
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/.
 */
package org.seedstack.business.assembler;

import org.seedstack.business.assembler.dsl.FluentAssembler;

/**
 * An assembler implementation contains the logic responsible for assembling an aggregate (or a
 * tuple of multiple aggregates) into into a DTO and back. Assemblers can be used by the {@link
 * FluentAssembler} DSL to execute complex mapping tasks.
 *
 * @param  the type of the aggregate root or of the {@link org.javatuples.Tuple} of aggregate
 *            roots.
 * @param  the type of the DTO.
 * @see FluentAssembler
 */
public interface Assembler {

    /**
     * Creates a new DTO and merge the given aggregate into it. Method {@link #createDto()} is called
     * to create the DTO instance, then {@link #mergeAggregateIntoDto(Object, Object)} is called to do
     * the merge.
     *
     * @param sourceAggregate the source aggregate.
     * @return the resulting dto.
     */
    default D createDtoFromAggregate(A sourceAggregate) {
        D dto = createDto();
        mergeAggregateIntoDto(sourceAggregate, dto);
        return dto;
    }

    /**
     * Merge a source aggregate into an existing target DTO.
     *
     * @param sourceAggregate the source aggregate.
     * @param targetDto       the target dto.
     */
    void mergeAggregateIntoDto(A sourceAggregate, D targetDto);

    /**
     * Merges a source DTO into an existing target aggregate root.
     *
     * @param sourceDto       the source dto.
     * @param targetAggregate the target aggregate.
     */
    void mergeDtoIntoAggregate(D sourceDto, A targetAggregate);

    /**
     * This method is responsible for creating a new DTO instance during the assembling task.
     *
     * @return a newly-created DTO instance.
     * @see #createDtoFromAggregate(Object)
     */
    D createDto();

    /**
     * The DTO class the assemblers works on.
     *
     * @return the DTO class.
     */
    Class getDtoClass();
}