1 files changed, 37 insertions, 0 deletions
diff --git a/core/src/main/scala/com/rockymadden/stringmetric/MetricDecorator.scala b/core/src/main/scala/com/rockymadden/stringmetric/MetricDecorator.scala
new file mode 100644
index 0000000..e14db86
--- /dev/null
+++ b/core/src/main/scala/com/rockymadden/stringmetric/MetricDecorator.scala
@@ -0,0 +1,37 @@
+package com.rockymadden.stringmetric
+
+import scala.collection.immutable.Map
+
+sealed trait MetricDecorator[A, B] {
+	val withMemoization: Metric[A, B]
+
+	val withTransform: (Transform[A] => Metric[A, B])
+}
+
+final case class StringMetricDecorator[A](sm: StringMetric[A]) extends MetricDecorator[Array[Char], A] {
+	override val withMemoization: StringMetric[A] = new StringMetric[A] {
+		private val base: StringMetric[A] = sm
+		private var memo: Map[(String, String), Option[A]] = Map()
+
+		override def compare(a: Array[Char], b: Array[Char]): Option[A] = compare(a.toString, b.toString)
+
+		override def compare(a: String, b: String): Option[A] = {
+			val t = (a, b)
+
+			if (memo.contains(t)) memo(t)
+			else {
+				memo = memo + (t -> base.compare(a, b))
+				memo(t)
+			}
+		}
+	}
+
+	override val withTransform: (StringTransform => StringMetric[A]) = (st) => new StringMetric[A] {
+		private val base: StringMetric[A] = sm
+		private val transform: StringTransform = st
+
+		override def compare(a: Array[Char], b: Array[Char]): Option[A] = base.compare(transform(a), transform(b))
+
+		override def compare(a: String, b: String): Option[A] = compare(a.toCharArray, b.toCharArray)
+	}
+}