org.http4k.lens.lens.kt Maven / Gradle / Ivy

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package org.http4k.lens

/**
 * A Lens provides the uni-directional extraction of an entity from a target.
 */
open class Lens(
    val meta: Meta,
    private val lensGet: (IN) -> FINAL
) : LensExtractor, Iterable {
    override fun iterator(): Iterator = listOf(meta).iterator()

    override fun toString(): String = "${if (meta.required) "Required" else "Optional"} ${meta.location} '${meta.name}'"

    override operator fun invoke(target: IN): FINAL = try {
        lensGet(target)
    } catch (e: LensFailure) {
        throw e
    } catch (e: Exception) {
        throw LensFailure(Invalid(meta), cause = e, target = target)
    }
}

/**
 * A BiDiLens provides the bi-directional extraction of an entity from a target, or the insertion of an entity
 * into a target.
 */
class BiDiLens(
    meta: Meta,
    get: (IN) -> FINAL,
    private val lensSet: (FINAL, IN) -> IN
) : LensInjector, Lens(meta, get) {

    @Suppress("UNCHECKED_CAST")
    override operator fun  invoke(value: FINAL, target: R): R = lensSet(value, target) as R
}