From 3fb07c6be05f39bdacf4a68c5b375471d74122e4 Mon Sep 17 00:00:00 2001
From: Fabio Scotto di Santolo <fabio.scottodisantolo@gmail.com>
Date: Tue, 28 Jan 2020 17:41:40 +0100
Subject: [PATCH] Implementazione di una classe per applicare la tecnica della
 Memoization

---
 .../java/org/gym/fp/fpjava/type/Memoizer.java | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)
 create mode 100644 functional-programming-java/src/main/java/org/gym/fp/fpjava/type/Memoizer.java

diff --git a/functional-programming-java/src/main/java/org/gym/fp/fpjava/type/Memoizer.java b/functional-programming-java/src/main/java/org/gym/fp/fpjava/type/Memoizer.java
new file mode 100644
index 0000000..21378fc
--- /dev/null
+++ b/functional-programming-java/src/main/java/org/gym/fp/fpjava/type/Memoizer.java
@@ -0,0 +1,19 @@
+package org.gym.fp.fpjava.type;
+
+import java.util.Map;
+import java.util.concurrent.ConcurrentHashMap;
+
+public final class Memoizer<T, U> {
+    private final Map<T, U> cache = new ConcurrentHashMap<>();
+
+    private Memoizer() {
+    }
+
+    public static <T, U> Function<T, U> memoize(Function<T, U> function) {
+        return new Memoizer<T, U>().doMemoize(function);
+    }
+
+    private Function<T, U> doMemoize(Function<T, U> function) {
+        return input -> cache.computeIfAbsent(input, function::apply);
+    }
+}