WIP: use L128X1024Mix for random generator

fixes #363

Author: Vladimir Sitnikov

CONTRIBUTING.md

@@ -37,4 +37,4 @@ Use _jqwik_ itself for all tests and properties.
 
 Use _AssertJ_ for non trivial assertions.
 
-Use `@ForAll Random random` parameter if you need a random value. 
+Use `@ForAll JqwikRandom random` parameter if you need a random value. 

api/build.gradle

@@ -53,4 +53,6 @@ signing {
 dependencies {
 	api("org.opentest4j:opentest4j:${opentest4jVersion}")
 	api("org.junit.platform:junit-platform-commons:${junitPlatformVersion}")
+	api(platform("org.apache.commons:commons-rng-bom:1.5"))
+	api("org.apache.commons:commons-rng-client-api")
 }

api/src/main/java/net/jqwik/api/Arbitraries.java

@@ -111,7 +111,7 @@ public static <T> Arbitrary<T> fromGenerator(RandomGenerator<T> generator) {
 	 * @param <T>       The type of values to generate
 	 * @return a new arbitrary instance
 	 */
-	public static <T> Arbitrary<T> randomValue(Function<Random, T> generator) {
+	public static <T> Arbitrary<T> randomValue(Function<JqwikRandom, T> generator) {
 		return fromGenerator(random -> Shrinkable.unshrinkable(generator.apply(random)));
 	}
 
@@ -120,8 +120,8 @@ public static <T> Arbitrary<T> randomValue(Function<Random, T> generator) {
 	 *
 	 * @return a new arbitrary instance
 	 */
-	public static Arbitrary<Random> randoms() {
-		return randomValue(random -> new Random(random.nextLong()));
+	public static Arbitrary<JqwikRandom> randoms() {
+		return randomValue(JqwikRandom::split);
 	}
 
 	/**

api/src/main/java/net/jqwik/api/JqwikRandom.java

@@ -0,0 +1,37 @@
+package net.jqwik.api;
+
+import net.jqwik.api.random.*;
+
+import org.apache.commons.rng.*;
+
+import java.util.*;
+
+public interface JqwikRandom extends UniformRandomProvider {
+	JqwikRandom jump();
+	
+	default JqwikRandom split() {
+		return split(this);
+	}
+	
+	JqwikRandom split(UniformRandomProvider source);
+	
+	JqwikRandomState saveState();
+	
+	void restoreState(JqwikRandomState state);
+	
+	default Random asJdkRandom() {
+		return new Random() {
+			@Override
+			protected int next(int bits) {
+				int next = JqwikRandom.this.nextInt();
+				next &= ((1L << bits) - 1);
+				return next;
+			}
+
+			@Override
+			public long nextLong() {
+				return JqwikRandom.this.nextLong();
+			}
+		};
+	}
+}

api/src/main/java/net/jqwik/api/RandomDistribution.java

@@ -1,7 +1,6 @@
 package net.jqwik.api;
 
 import java.math.*;
-import java.util.*;
 
 import org.apiguardian.api.*;
 
@@ -61,7 +60,7 @@ interface RandomNumericGenerator {
 		 *
 		 * @return an instance of BigInteger. Never {@code null}.
 		 */
-		BigInteger next(Random random);
+		BigInteger next(JqwikRandom random);
 	}
 
 	/**

api/src/main/java/net/jqwik/api/RandomGenerator.java

@@ -4,6 +4,8 @@
 import java.util.function.*;
 import java.util.stream.*;
 
+import net.jqwik.api.random.*;
+
 import org.apiguardian.api.*;
 
 import static org.apiguardian.api.API.Status.*;
@@ -19,13 +21,13 @@ abstract class RandomGeneratorFacade {
 			implementation = FacadeLoader.load(RandomGeneratorFacade.class);
 		}
 
-		public abstract <T, U> Shrinkable<U> flatMap(Shrinkable<T> self, Function<T, RandomGenerator<U>> mapper, long nextLong);
+		public abstract <T, U> Shrinkable<U> flatMap(Shrinkable<T> self, Function<T, RandomGenerator<U>> mapper, JqwikRandomState nextLong);
 
 		public abstract <T, U> Shrinkable<U> flatMap(
 				Shrinkable<T> wrappedShrinkable,
 				Function<T, Arbitrary<U>> mapper,
 				int genSize,
-				long nextLong,
+				JqwikRandomState nextLong,
 				boolean withEmbeddedEdgeCases
 		);
 
@@ -44,7 +46,7 @@ public abstract <T, U> Shrinkable<U> flatMap(
 	 * @param random the source of randomness. Injected by jqwik itself.
 	 * @return the next generated value wrapped within the Shrinkable interface. The method must ALWAYS return a next value.
 	 */
-	Shrinkable<T> next(Random random);
+	Shrinkable<T> next(JqwikRandom random);
 
 	@API(status = INTERNAL)
 	default <U> RandomGenerator<U> map(Function<T, U> mapper) {
@@ -63,7 +65,7 @@ default <U> RandomGenerator<U> mapShrinkable(Function<Shrinkable<T>, Shrinkable<
 	default <U> RandomGenerator<U> flatMap(Function<T, RandomGenerator<U>> mapper) {
 		return random -> {
 			Shrinkable<T> wrappedShrinkable = RandomGenerator.this.next(random);
-			return RandomGeneratorFacade.implementation.flatMap(wrappedShrinkable, mapper, random.nextLong());
+			return RandomGeneratorFacade.implementation.flatMap(wrappedShrinkable, mapper, random.split().saveState());
 		};
 	}
 
@@ -72,7 +74,7 @@ default <U> RandomGenerator<U> flatMap(Function<T, Arbitrary<U>> mapper, int gen
 		return random -> {
 			Shrinkable<T> wrappedShrinkable = RandomGenerator.this.next(random);
 			return RandomGeneratorFacade.implementation
-						   .flatMap(wrappedShrinkable, mapper, genSize, random.nextLong(), withEmbeddedEdgeCases);
+						   .flatMap(wrappedShrinkable, mapper, genSize, random.split().saveState(), withEmbeddedEdgeCases);
 		};
 	}
 
@@ -87,7 +89,7 @@ default RandomGenerator<T> withEdgeCases(int genSize, EdgeCases<T> edgeCases) {
 	}
 
 	@API(status = INTERNAL)
-	default Stream<Shrinkable<T>> stream(Random random) {
+	default Stream<Shrinkable<T>> stream(JqwikRandom random) {
 		return Stream.generate(() -> this.next(random));
 	}
 

api/src/main/java/net/jqwik/api/Shrinkable.java

@@ -5,6 +5,8 @@
 import java.util.function.*;
 import java.util.stream.*;
 
+import net.jqwik.api.random.*;
+
 import org.apiguardian.api.*;
 
 import static org.apiguardian.api.API.Status.*;
@@ -26,7 +28,7 @@ abstract class ShrinkableFacade {
 
 		public abstract <T> Shrinkable<T> filter(Shrinkable<T> self, Predicate<T> filter);
 
-		public abstract <T, U> Shrinkable<U> flatMap(Shrinkable<T> self, Function<T, Arbitrary<U>> flatMapper, int tries, long randomSeed);
+		public abstract <T, U> Shrinkable<U> flatMap(Shrinkable<T> self, Function<T, Arbitrary<U>> flatMapper, int tries, JqwikRandomState randomSeed);
 	}
 
 	static <T> Shrinkable<T> unshrinkable(@Nullable T value) {
@@ -106,7 +108,7 @@ default Shrinkable<T> filter(Predicate<T> filter) {
 		return ShrinkableFacade.implementation.filter(this, filter);
 	}
 
-	default <U> Shrinkable<U> flatMap(Function<T, Arbitrary<U>> flatMapper, int tries, long randomSeed) {
+	default <U> Shrinkable<U> flatMap(Function<T, Arbitrary<U>> flatMapper, int tries, JqwikRandomState randomSeed) {
 		return ShrinkableFacade.implementation.flatMap(this, flatMapper, tries, randomSeed);
 	}
 

api/src/main/java/net/jqwik/api/facades/ShrinkingSupportFacade.java

@@ -1,7 +1,5 @@
 package net.jqwik.api.facades;
 
-import java.util.*;
-
 import org.apiguardian.api.*;
 
 import net.jqwik.api.*;
@@ -17,9 +15,9 @@ public abstract class ShrinkingSupportFacade {
 		implementation = FacadeLoader.load(ShrinkingSupportFacade.class);
 	}
 
-	public abstract <T> T falsifyThenShrink(Arbitrary<? extends T> arbitrary, Random random, Falsifier<T> falsifier);
+	public abstract <T> T falsifyThenShrink(Arbitrary<? extends T> arbitrary, JqwikRandom random, Falsifier<T> falsifier);
 
-	public abstract <T> T falsifyThenShrink(RandomGenerator<? extends T> arbitrary, Random random, Falsifier<T> falsifier);
+	public abstract <T> T falsifyThenShrink(RandomGenerator<? extends T> arbitrary, JqwikRandom random, Falsifier<T> falsifier);
 
 	public abstract <T> T shrink(
 			Shrinkable<T> falsifiedShrinkable,

api/src/main/java/net/jqwik/api/facades/TestingSupportFacade.java

@@ -13,7 +13,7 @@ public abstract class TestingSupportFacade {
 		implementation = FacadeLoader.load(TestingSupportFacade.class);
 	}
 
-	public abstract <T> Shrinkable<T> generateUntil(RandomGenerator<T> generator, Random random, Function<T, Boolean> condition);
+	public abstract <T> Shrinkable<T> generateUntil(RandomGenerator<T> generator, JqwikRandom random, Function<T, Boolean> condition);
 
 	public abstract String singleLineReport(Object any);
 

api/src/main/java/net/jqwik/api/random/JqwikRandomSeed.java

@@ -0,0 +1,4 @@
+package net.jqwik.api.random;
+
+public interface JqwikRandomSeed {
+}