From b74d68227dc7c05e24705e3064ef961f95b8b729 Mon Sep 17 00:00:00 2001
From: Michael Williamson <mike@zwobble.org>
Date: Sun, 4 Oct 2015 17:52:29 +0100
Subject: Throw exception if assigning value of wrong type

---
 src/main/java/org/zwobble/couscous/util/CousCousMaps.java | 14 ++++++++++++++
 1 file changed, 14 insertions(+)
 create mode 100644 src/main/java/org/zwobble/couscous/util/CousCousMaps.java

(limited to 'src/main/java/org/zwobble/couscous/util/CousCousMaps.java')

diff --git a/src/main/java/org/zwobble/couscous/util/CousCousMaps.java b/src/main/java/org/zwobble/couscous/util/CousCousMaps.java
new file mode 100644
index 0000000..5fb4dca
--- /dev/null
+++ b/src/main/java/org/zwobble/couscous/util/CousCousMaps.java
@@ -0,0 +1,14 @@
+package org.zwobble.couscous.util;
+
+import java.util.Map;
+import java.util.function.Function;
+
+import static java.util.stream.Collectors.toMap;
+
+public class CousCousMaps {
+    public static <K1, K2, V> Map<K2, V> mapKeys(Map<K1, V> map, Function<K1, K2> func) {
+        return map.entrySet()
+            .stream()
+            .collect(toMap(entry -> func.apply(entry.getKey()), entry -> entry.getValue()));
+    }
+}
-- 
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