From 4c85e56c803612faed22b63e2617be799d6e879c Mon Sep 17 00:00:00 2001
From: Paul Campbell <pcampbell@kemitix.net>
Date: Sat, 7 Oct 2017 18:56:38 +0100
Subject: [PATCH] TypeAlias.map(): added

---
 src/main/java/net/kemitix/mon/TypeAlias.java     | 16 +++++++++++++++-
 src/test/java/net/kemitix/mon/TypeAliasTest.java | 15 +++++++++++++++
 2 files changed, 30 insertions(+), 1 deletion(-)

diff --git a/src/main/java/net/kemitix/mon/TypeAlias.java b/src/main/java/net/kemitix/mon/TypeAlias.java
index 2dd5e6e..2f18f13 100644
--- a/src/main/java/net/kemitix/mon/TypeAlias.java
+++ b/src/main/java/net/kemitix/mon/TypeAlias.java
@@ -21,6 +21,8 @@
 
 package net.kemitix.mon;
 
+import java.util.function.Function;
+
 /**
  * Type Alias for other types.
  *
@@ -45,6 +47,19 @@ public abstract class TypeAlias<T> {
         this.value = value;
     }
 
+
+    /**
+     * Map the TypeAlias into another value.
+     *
+     * @param f   the function to create the new value
+     * @param <R> the type of the new value
+     *
+     * @return a TypeAlias
+     */
+    public <R> R map(final Function<T, R> f) {
+        return f.apply(value);
+    }
+
     @Override
     public final int hashCode() {
         return value.hashCode();
@@ -71,5 +86,4 @@ public abstract class TypeAlias<T> {
     public final T getValue() {
         return value;
     }
-
 }
diff --git a/src/test/java/net/kemitix/mon/TypeAliasTest.java b/src/test/java/net/kemitix/mon/TypeAliasTest.java
index 069c6ab..b6fb753 100644
--- a/src/test/java/net/kemitix/mon/TypeAliasTest.java
+++ b/src/test/java/net/kemitix/mon/TypeAliasTest.java
@@ -2,6 +2,8 @@ package net.kemitix.mon;
 
 import org.junit.Test;
 
+import java.util.function.Function;
+
 import static org.assertj.core.api.Assertions.assertThat;
 
 public class TypeAliasTest {
@@ -59,10 +61,23 @@ public class TypeAliasTest {
     public void shouldHaveSameToStringAsAliasedType() throws Exception {
         //given
         final String value = "value";
+        //when
         final AnAlias anAlias = AnAlias.of(value);
+        //then
         assertThat(anAlias.toString()).isEqualTo(value);
     }
 
+    @Test
+    public void shouldMapTypeAlias() {
+        //given
+        final AnAlias anAlias = AnAlias.of("text");
+        final Function<String, String> function = v -> v;
+        //when
+        final String value = anAlias.map(function);
+        //then
+        assertThat(value).isEqualTo("text");
+    }
+
     private static class AnAlias extends TypeAlias<String> {
 
         /**