8180805: move RandomFactory to the top level testlibrary

Reviewed-by: bpb, rriggs

test/lib/jdk/test/lib/RandomFactory.java

@@ -0,0 +1,103 @@
+/*
+ * Copyright (c) 2015, 2017, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+package jdk.test.lib;
+
+import java.util.Random;
+import java.util.SplittableRandom;
+
+/**
+ * Factory class which generates and prints to STDOUT a long-valued seed
+ * for use in initializing a PRNG.  An instance of {@code Random} or
+ * {@code SplittableRandom} may likewise be obtained.
+ */
+public class RandomFactory {
+    /**
+     * Attempt to obtain the seed from the value of the "seed" property.
+     * @return The seed or {@code null} if the "seed" property was not set or
+     *         could not be parsed.
+     */
+    private static Long getSystemSeed() {
+        Long seed = null;
+        try {
+            // note that Long.valueOf(null) also throws a
+            // NumberFormatException so if the property is undefined this
+            // will still work correctly
+            seed = Long.valueOf(System.getProperty("seed"));
+        } catch (NumberFormatException e) {
+            // do nothing: seed is still null
+        }
+
+        return seed;
+    }
+
+    /**
+     * Obtain a seed from an independent PRNG.
+     *
+     * @return A random seed.
+     */
+    private static long getRandomSeed() {
+        return new Random().nextLong();
+    }
+
+    /**
+     * Obtain and print to STDOUT a seed appropriate for initializing a PRNG.
+     * If the system property "seed" is set and has value which may be correctly
+     * parsed it is used, otherwise a seed is generated using an independent
+     * PRNG.
+     *
+     * @return The seed.
+     */
+    public static long getSeed() {
+        Long seed = getSystemSeed();
+        if (seed == null) {
+            seed = getRandomSeed();
+        }
+        System.out.println("Seed from RandomFactory = "+seed+"L");
+        return seed;
+    }
+
+    /**
+     * Obtain and print to STDOUT a seed and use it to initialize a new
+     * {@code Random} instance which is returned. If the system
+     * property "seed" is set and has value which may be correctly parsed it
+     * is used, otherwise a seed is generated using an independent PRNG.
+     *
+     * @return The {@code Random} instance.
+     */
+    public static Random getRandom() {
+        return new Random(getSeed());
+    }
+
+    /**
+     * Obtain and print to STDOUT a seed and use it to initialize a new
+     * {@code SplittableRandom} instance which is returned. If the system
+     * property "seed" is set and has value which may be correctly parsed it
+     * is used, otherwise a seed is generated using an independent PRNG.
+     *
+     * @return The {@code SplittableRandom} instance.
+     */
+    public static SplittableRandom getSplittableRandom() {
+        return new SplittableRandom(getSeed());
+    }
+}