From e4aecc1b476dcfeeb9f9d5874f0c3595f88e09a3 Mon Sep 17 00:00:00 2001
From: Chris Larsen <clarsen@yahoo-inc.com>
Date: Wed, 2 Aug 2017 23:45:03 -0700
Subject: [PATCH] [core] Add a Fisher-Yates array shuffle to the Utils class.
---
core/src/main/java/com/yahoo/ycsb/Utils.java | 15 +++++++++++++++
1 file changed, 15 insertions(+)
diff --git a/core/src/main/java/com/yahoo/ycsb/Utils.java b/core/src/main/java/com/yahoo/ycsb/Utils.java
index 9a95cbd6..ade6a1ce 100644
--- a/core/src/main/java/com/yahoo/ycsb/Utils.java
+++ b/core/src/main/java/com/yahoo/ycsb/Utils.java
@@ -226,4 +226,19 @@ public final class Utils {
}
return map;
}
+
+ /**
+ * Simple Fisher-Yates array shuffle to randomize discrete sets.
+ * @param array The array to randomly shuffle.
+ * @return The shuffled array.
+ */
+ public static <T> T [] shuffleArray(final T[] array) {
+ for (int i = array.length -1; i > 0; i--) {
+ final int idx = RAND.nextInt(i + 1);
+ final T temp = array[idx];
+ array[idx] = array[i];
+ array[i] = temp;
+ }
+ return array;
+ }
}
--
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