zio.cache.Lookup.scala Maven / Gradle / Ivy
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/*
* Copyright 2020-2023 John A. De Goes and the ZIO Contributors
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package zio.cache
import zio.ZIO
/**
* A `Lookup` represents a lookup function that, given a key of type `Key`, can
* return a `ZIO` effect that will either produce a value of type `Value` or
* fail with an error of type `Error` using an environment of type
* `Environment`.
*
* You can think of a `Lookup` as an effectual function that computes a value
* given a key. Given any effectual function you can convert it to a lookup
* function for a cache by using the `Lookup` constructor.
*/
final case class Lookup[-Key, -Environment, +Error, +Value](lookup: Key => ZIO[Environment, Error, Value])
extends (Key => ZIO[Environment, Error, Value]) {
/**
* Computes a value for the specified key or fails with an error.
*/
def apply(key: Key): ZIO[Environment, Error, Value] =
lookup(key)
}