org.babyfish.jimmer.sql.DraftInterceptor.kt Maven / Gradle / Ivy

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A revolutionary ORM framework for both java and kotlin

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package org.babyfish.jimmer.sql

import org.babyfish.jimmer.Draft
import org.babyfish.jimmer.meta.TypedProp

/**
 * Before saving draft, give user a chance to modify it
 *
 * This interface is very similar to another interface
 * [DraftPreProcessor],
 * the differences between the two are as follows:
 * 

 * [DraftPreProcessor] is more conducive to SQL optimization, but has weaker functions
 * This interface has stronger features but is not carp SQL optimized
 * 
 * 
 *
 * It also queries the original entity with
 * `id`, `key` and other properties returned by [.dependencies] to help user to decide how to modify draft
 *
 * The default behavior of `save` with `UPDATE_ONLY` or `update` is not querying original entity.
 * However, if [.dependencies] returns some properties which is neither `id` nor `key`,
 * the default behavior will be broken, original entity will be queried even if the save mode is `UPDATE_ONLY`
 *
 * @param  The entity type
 * @param  The draft type
 *
 * @see DraftPreProcessor
 */
interface DraftInterceptor {

    /**
     * Adjust draft before save
     * @param draft The draft can be modified, `id` and `key` properties cannot be changed, otherwise, exception will be raised.
     * @param original The original object
     *
     *  * null for insert
     *  * non-null for update, with `id`, `key` and other properties
     * returned by [.dependencies]
     */
    fun beforeSave(draft: D, original: E?)

    /**
     * Specify which properties of original entity must be loaded
     *
     * Note
     * 
     *  The return value must be stable, It will only be called once, so an unstable return is meaningless
     *  All elements must be properties which is mapped by database field directly
     * 
     *
     * @return The properties must be loaded, can return null.
     */
    fun dependencies(): Collection>? {
        return emptyList()
    }
}