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/*
* Copyright 2019 Scanamo
*
* 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 org.scanamo
import cats.Parallel
import cats.kernel.Monoid
import software.amazon.awssdk.services.dynamodb.model.AttributeValue
import java.util.{ HashMap, Map => JMap }
import cats.syntax.apply._
import cats.syntax.semigroup._
import scala.annotation.tailrec
/** A `DynamoObject` is a map of strings to values that can be embedded into an `AttributeValue`.
*/
sealed abstract class DynamoObject extends Product with Serializable { self =>
import DynamoObject._
protected def internalToMap: Map[String, DynamoValue]
/** Gets the value mapped to `key` if it exists
*/
final def apply(key: String): Option[DynamoValue] =
self match {
case Empty => None
case Strict(xs) => val x = xs.get(key); if (x eq null) None else Some(DynamoValue.fromAttributeValue(x))
case Pure(xs) => xs.get(key)
case Concat(xs, ys) => xs(key) orElse ys(key)
}
final def get[A: DynamoFormat](key: String): Either[DynamoReadError, A] =
apply(key).getOrElse(DynamoValue.nil).as[A]
/** Gets the size of the map
*/
final def size: Int =
self match {
case Empty => 0
case Strict(xs) => xs.size
case Pure(xs) => xs.size
case Concat(xs, ys) => xs.size + ys.size
}
/** Checks if the map is empty
*/
final def isEmpty: Boolean =
self match {
case Empty => true
case _ => false
}
/** Chekcs if the map is not empty
*/
final def nonEmpty: Boolean = !isEmpty
/** Checks if the map contains a certain `key`
*/
final def contains(key: String): Boolean =
self match {
case Empty => false
case Strict(xs) => xs.containsKey(key)
case Pure(xs) => xs.contains(key)
case Concat(xs, ys) => xs.contains(key) || ys.contains(key)
}
/** Gets the list of keys in the map
*/
final def keys: Iterable[String] =
self match {
case Empty => Iterable.empty[String]
case Strict(xs) =>
new Iterable[String] {
final val iterator = new Iterator[String] {
private[this] val underlying = xs.keySet.iterator
final def hasNext = underlying.hasNext
final def next() = underlying.next
}
}
case Pure(xs) => xs.keys
case Concat(xs, ys) => xs.keys ++ ys.keys
}
/** Gets the list of values in the map
*/
final def values: Iterable[DynamoValue] =
self match {
case Empty => Iterable.empty[DynamoValue]
case Strict(xs) =>
new Iterable[DynamoValue] {
final val iterator = new Iterator[DynamoValue] {
private[this] val underlying = xs.values.iterator
final def hasNext = underlying.hasNext
final def next() = DynamoValue.fromAttributeValue(underlying.next)
}
}
case Pure(xs) => xs.values
case Concat(xs, ys) => xs.values ++ ys.values
}
/** Transforms the map by assigning values to new keys
*/
final def mapKeys(f: String => String): DynamoObject =
self match {
case Empty => Empty
case Strict(xs) => Pure(unsafeToScalaMap(xs).map { case (k, v) => f(k) -> DynamoValue.fromAttributeValue(v) })
case Pure(xs) => Pure(xs.map { case (k, v) => f(k) -> v })
case Concat(xs, ys) => Concat(xs.mapKeys(f), ys.mapKeys(f))
}
// TODO: find a better name
// TODO: mark as private?
final def toJavaMap: JMap[String, AttributeValue] =
self match {
case Empty => unsafeToJavaMap(Map.empty)
case Strict(xs) => xs
case Pure(xs) => unsafeToJavaMap(xs.mapValues(_.toAttributeValue).toMap)
case Concat(xs, ys) => unsafeMerge(xs.toJavaMap, ys.toJavaMap)
}
/** Make a value out of this map
*/
final def toDynamoValue: DynamoValue = DynamoValue.fromDynamoObject(self)
/** Make an AWS SDK value out of this map
*/
final def toAttributeValue: AttributeValue = AttributeValue.builder.m(toJavaMap).build
/** Builds a [[scala.collection.Map]] if this map is made entirely of values of type `V`
*/
final def toMap[V](implicit D: DynamoFormat[V]): Either[DynamoReadError, Map[String, V]] =
self match {
case Empty => Right(Map.empty)
case Strict(xs) =>
xs.entrySet.stream.reduce[Either[DynamoReadError, Map[String, V]]](
Right(Map.empty),
(xs0, e) => (xs0, D.read(e.getValue)).mapN((xs, x) => xs + (e.getKey -> x)),
(xs0, ys0) => (xs0, ys0).mapN(_ ++ _)
)
case Pure(xs) =>
xs.foldLeft[Either[DynamoReadError, Map[String, V]]](Right(Map.empty)) {
case (e @ Left(_), _) => e
case (Right(m), (k, x)) => D.read(x).right.map(x => m + (k -> x))
}
case Concat(xs0, ys0) => (xs0.toMap, ys0.toMap).mapN(_ ++ _)
}
/** Builds a map where the keys are transformed to match the convention for expression attribute values in DynamoDB
* operations See
* [[https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/Expressions.ExpressionAttributeValues.html]]
*/
final def toExpressionAttributeValues: Option[JMap[String, AttributeValue]] =
self match {
case Empty => None
case Strict(xs) =>
Some(
unsafeTransform(m =>
xs.entrySet.stream.forEach { x =>
m.put(":" ++ x.getKey, x.getValue); ()
}
)
)
case Pure(xs) => Some(unsafeTransform(m => xs foreach { case (k, x) => m.put(":" ++ k, x.toAttributeValue) }))
case Concat(xs, ys) =>
(xs.toExpressionAttributeValues, ys.toExpressionAttributeValues).mapN(unsafeMerge)
}
/** Add an entry to the map or overwrites the existing value if there
*/
final def add(key: String, value: DynamoValue): DynamoObject =
self match {
case Empty => Pure(Map(key -> value))
case xs: Strict => Concat(singleton(key, value), xs)
case Pure(xs) => Pure(xs + (key -> value))
case o @ Concat(Strict(_), Strict(_)) => Concat(singleton(key, value), o)
case Concat(Strict(xs), ys) => Concat(Strict(xs), ys.add(key, value))
case Concat(xs, Strict(ys)) => Concat(xs.add(key, value), Strict(ys))
case Concat(xs, ys) => Concat(xs.add(key, value), ys)
}
/** Remove an entry from the map if there
*/
final def remove(key: String): DynamoObject =
self match {
case Empty => Empty
case Strict(xs) => Pure((unsafeToScalaMap(xs) - key).mapValues(DynamoValue.fromAttributeValue).toMap)
case Pure(xs) => Pure(xs - key)
case Concat(xs, ys) if xs.contains(key) => Concat(xs.remove(key), ys)
case Concat(xs, ys) => Concat(xs, ys.remove(key))
}
/** Operator alias for `add`
*/
final def +(x: (String, DynamoValue)): DynamoObject = self.add(x._1, x._2)
/** Operator alias for `remove`
*/
final def -(key: String): DynamoObject = self remove key
/** Concatenates two maps
*/
final def concat(that: DynamoObject): DynamoObject =
if (self.isEmpty) that
else if (that.isEmpty) self
else Concat(self, that)
/** Operator alias for `concat`
*/
final def <>(that: DynamoObject): DynamoObject = self concat that
/** Traverse the object in parallel fashion and build up monoidal structure
*/
final def parTraverse[F[_]: Parallel, M: Monoid](f: DynamoValue => F[M]): F[M] =
parTraverseWith(f)(Monoid[M].empty)(_ |+| _)
/** Traverse the object in parallel foshiono and build up a result out of each value
*/
final def parTraverseWith[F[_]: Parallel, M](f: DynamoValue => F[M])(z: M)(c: (M, M) => M): F[M] =
parTraverseWithKey((_, dv) => f(dv))(z)(c)
/** Traverse the object in parallel fashion and build up a result out of each value and its label
*/
final def parTraverseWithKey[F[_], M](
f: (String, DynamoValue) => F[M]
)(z: M)(c: (M, M) => M)(implicit F: Parallel[F]): F[M] = {
@tailrec def parTraverseWithKey_(xs: List[DynamoObject], r: F.F[M]): F.F[M] =
xs match {
case Nil =>
r
case Empty :: xs =>
parTraverseWithKey_(xs, r)
case Strict(ys) :: xs =>
val r2 = ys.entrySet.stream.reduce[F.F[M]](
r,
(fm: F.F[M], kv: JMap.Entry[String, AttributeValue]) =>
F.apply.map2(fm, F.parallel(f(kv.getKey, DynamoValue.fromAttributeValue(kv.getValue))))(c),
(x: F.F[M], y: F.F[M]) => F.apply.map2(x, y)(c)
)
parTraverseWithKey_(xs, r2)
case Pure(ys) :: xs =>
val r2 = ys.foldLeft(r) { case (fm, (k, dv)) =>
F.apply.map2(fm, F.parallel(f(k, dv)))(c)
}
parTraverseWithKey_(xs, r2)
case Concat(ys1, ys2) :: xs =>
parTraverseWithKey_(ys1 :: ys2 :: xs, r)
}
F.sequential(parTraverseWithKey_(List(self), F.applicative.pure(z)))
}
/** Traverse the object into a monoidal structure
*/
final def traverse[M: Monoid](f: DynamoValue => M): M =
traverseWith(f)(Monoid[M].empty)(_ |+| _)
/** Traverse the object and build up a result out of each value
*/
final def traverseWith[M](f: DynamoValue => M)(z: M)(c: (M, M) => M): M =
traverseWithKey((_, dv) => f(dv))(z)(c)
/** Traverse the object and build up a result out of each value and its label
*/
final def traverseWithKey[M](f: (String, DynamoValue) => M)(z: M)(c: (M, M) => M): M = {
@tailrec def traverseWithKey_(xs: List[DynamoObject], r: M): M =
xs match {
case Nil => r
case Empty :: xs => traverseWithKey_(xs, r)
case Strict(ys) :: xs =>
val r2 = ys.entrySet.stream.reduce[M](
r,
(m, kv) => c(m, f(kv.getKey, DynamoValue.fromAttributeValue(kv.getValue))),
(x, y) => c(x, y)
)
traverseWithKey_(xs, r2)
case Pure(ys) :: xs =>
val r2 = ys.foldLeft(z) { case (m, (k, dv)) => c(m, f(k, dv)) }
traverseWithKey_(xs, r2)
case Concat(ys1, ys2) :: xs =>
traverseWithKey_(ys1 :: ys2 :: xs, r)
}
traverseWithKey_(List(self), z)
}
final override def equals(that: Any): Boolean =
that.isInstanceOf[DynamoObject] && (internalToMap == that.asInstanceOf[DynamoObject].internalToMap)
final override def hashCode(): Int = internalToMap.hashCode
}
object DynamoObject {
private[DynamoObject] case object Empty extends DynamoObject {
final def internalToMap = Map.empty
}
final private[DynamoObject] case class Strict(xs: JMap[String, AttributeValue]) extends DynamoObject {
final def internalToMap = unsafeToScalaMap(xs).mapValues(DynamoValue.fromAttributeValue).toMap
}
final private[DynamoObject] case class Pure(xs: Map[String, DynamoValue]) extends DynamoObject {
final def internalToMap = xs
}
final private[DynamoObject] case class Concat(xs: DynamoObject, ys: DynamoObject) extends DynamoObject {
final def internalToMap = xs.internalToMap ++ ys.internalToMap
}
/** Builds a map from a Java Map of attribute values
*/
def apply(xs: JMap[String, AttributeValue]): DynamoObject = if (xs.isEmpty) Empty else Strict(xs)
/** Builds a map from an arbitrary number of `(String, DynamoValue)` pairs
*/
def apply(xs: (String, DynamoValue)*): DynamoObject = apply(xs.toMap)
/** Builds a map from a [[scala.collection.Map]] of values
*/
def apply(xs: Map[String, DynamoValue]): DynamoObject = if (xs.isEmpty) Empty else Pure(xs)
/** Builds a map from an arbitrary number of `(String, A)` pairs for any `A` that can be turned into a value
*/
def apply[A](xs: (String, A)*)(implicit D: DynamoFormat[A]): DynamoObject =
apply(xs.foldLeft(Map.empty[String, DynamoValue]) { case (m, (k, x)) => m + (k -> D.write(x)) })
/** The empty map
*/
val empty: DynamoObject = Empty
/** Builds a singleton map
*/
def singleton(key: String, x: DynamoValue): DynamoObject = Pure(Map(key -> x))
/** Builds a map from an iterable collection of `(String, DynamoValue)` pairs
*/
def fromIterable(xs: Iterable[(String, DynamoValue)]): DynamoObject = apply(xs.toMap)
private[DynamoObject] def unsafeToJavaMap(m: Map[String, AttributeValue]): JMap[String, AttributeValue] = {
val n = new HashMap[String, AttributeValue](m.size, 1)
m foreach { case (k, x) => n.put(k, x) }
n
}
private[DynamoObject] def unsafeToScalaMap(m: JMap[String, AttributeValue]): Map[String, AttributeValue] = {
val builder = Map.newBuilder[String, AttributeValue]
builder.sizeHint(m.size)
val iterator = m.entrySet.iterator
while (iterator.hasNext) {
val e = iterator.next
builder += e.getKey -> e.getValue
}
builder.result()
}
private[DynamoObject] def unsafeTransform(f: JMap[String, AttributeValue] => Unit): JMap[String, AttributeValue] = {
val m = new java.util.HashMap[String, AttributeValue]
f(m)
m
}
private[DynamoObject] def unsafeMerge[K, V](xs: JMap[K, V], ys: JMap[K, V]): JMap[K, V] = {
val m = new java.util.HashMap[K, V](xs.size + ys.size)
m.putAll(xs)
m.putAll(ys)
m
}
}
