SI-9059 Random.alphanumeric is inefficient

Generate alphanumeric values by taking random element of string
containing all alphanumerics.

Instead of generating nextPrintableChar then filtering for
alphanumerics, we can just take from a string containing all
alphanumerics.  This provides a significant performance improvement.

1 files changed, 15 insertions, 0 deletions

diff --git a/test/junit/scala/util/RandomTest.scala b/test/junit/scala/util/RandomTest.scala
new file mode 100644
index 0000000000..32959675ee
--- /dev/null
+++ b/test/junit/scala/util/RandomTest.scala
@@ -0,0 +1,15 @@
+package scala.util
+
+import org.junit.{ Assert, Test }
+
+class RandomTest {
+  // Test for SI-9059
+  @Test def testAlphanumeric: Unit = {
+    def isAlphaNum(c: Char) = (c >= 'A' && c <= 'Z') || (c >= 'a' && c <= 'z') || (c >= '0' && c <= '9')
+
+    val items = Random.alphanumeric.take(100000)
+    for (c <- items) {
+      Assert.assertTrue(s"$c should be alphanumeric", isAlphaNum(c))
+    }
+  }
+}