Minor improvements

Author: cowtowncoder

run.sh

@@ -1,3 +1,3 @@
 #!/bin/sh
 
-java -classpath build/classes $*
+java -classpath target/classes $*

src/main/java/com/fasterxml/uuid/Jug.java

@@ -49,7 +49,7 @@ protected static void printUsage()
         String clsName = Jug.class.getName();
         System.err.println("Usage: java "+clsName+" [options] type");
         System.err.println("Where options are:");
-        System.err.println("  --count / -c <number>: will generate <number> UUIDs (default: 1");
+        System.err.println("  --count / -c <number>: will generate <number> UUIDs (default: 1)");
         System.err.println("  --ethernet-address / -e <ether-address>: defines the ethernet address");
         System.err.println("    (in xx:xx:xx:xx:xx:xx notation, usually obtained using 'ifconfig' etc)");
         System.err.println("    to use with time-based UUID generation");

src/main/java/com/fasterxml/uuid/impl/RandomBasedGenerator.java

@@ -33,6 +33,13 @@ public class RandomBasedGenerator extends NoArgGenerator
      * Random number generator that this generator uses.
      */
     protected final Random _random;
+
+    /**
+     * Looks like {@link SecureRandom} implementation is more efficient
+     * using single call access (compared to basic {@link java.util.Random}),
+     * so let's use that knowledge to our benefit.
+     */
+    protected final boolean _secureRandom;
 
     /**
      * @param rnd Random number generator to use for generating UUIDs; if null,
@@ -51,6 +58,9 @@ public RandomBasedGenerator(Random rnd)
             if (_sharedRandom == null) {
                 _sharedRandom = rnd = new SecureRandom();
             }
+            _secureRandom = true;
+        } else {
+            _secureRandom = (rnd instanceof SecureRandom);
         }
         _random = rnd;
     }
@@ -71,9 +81,44 @@ public RandomBasedGenerator(Random rnd)
      */
 
     @Override
-    public UUID generate() {
-        long r1 = _random.nextLong();
-        long r2 = _random.nextLong();
+    public UUID generate()
+    {
+        /* 14-Oct-2010, tatu: Surprisingly, variant for reading byte array is
+         *   tad faster for SecureRandom... so let's use that then
+         */
+        long r1, r2;
+
+        if (_secureRandom) {
+            final byte[] buffer = new byte[16];
+            _random.nextBytes(buffer);
+            r1 = _toLong(buffer, 0);
+            r2 = _toLong(buffer, 1);
+        } else {
+            r1 = _random.nextLong();
+            r2 = _random.nextLong();
+        }
         return UUIDUtil.constructUUID(UUIDType.RANDOM_BASED, r1, r2);
     }
+
+    /*
+    /**********************************************************************
+    /* Internal methods
+    /**********************************************************************
+     */
+
+    private final static long _toLong(byte[] buffer, int offset)
+    {
+        long l1 = _toInt(buffer, offset);
+        long l2 = _toInt(buffer, offset+4);
+        long l = (l1 << 32) + ((l2 << 32) >>> 32);
+        return l;
+    }
+
+    private final static long _toInt(byte[] buffer, int offset)
+    {
+        return (buffer[offset] << 24)
+            + ((buffer[++offset] & 0xFF) << 16)
+            + ((buffer[++offset] & 0xFF) << 8)
+            + (buffer[++offset] & 0xFF);
+    }
 }

src/main/java/test/MeasurePerformance.java src/main/java/perf/MeasurePerformance.java

@@ -1,4 +1,4 @@
-package test;
+package perf;
 
 import java.util.UUID;