Take samples from generators

core/src/main/java/org/quicktheories/core/Gen.java

@@ -1,5 +1,7 @@
 package org.quicktheories.core;
 
+import java.util.ArrayList;
+import java.util.List;
 import java.util.Optional;
 import java.util.function.BiFunction;
 import java.util.function.Function;
@@ -9,7 +11,10 @@
 import org.quicktheories.api.Function3;
 import org.quicktheories.api.Function4;
 import org.quicktheories.api.Function5;
+import org.quicktheories.impl.BoundarySkewedDistribution;
 import org.quicktheories.impl.Constraint;
+import org.quicktheories.impl.Distribution;
+import org.quicktheories.impl.SimpleRandomnessSource;
 
 /**
  * (Psuedo)randomly generates instances of T
@@ -26,6 +31,74 @@ public interface Gen<T> extends AsString<T>{
    */
   T generate(RandomnessSource in);
 
+  /**
+   * Prints a single example generated by this generator to standard out
+   */
+  default void printExample() {
+    System.out.println(asString(example()));
+  }
+
+  /**
+   * Prints count examples generated by this generator to standard out
+   * @param count the number of examples to print
+   */
+  default void printExamples(int count) {
+    printExamples(count, System.nanoTime());
+  }
+
+  /**
+   * Prints count examples generated by this generator to standard out, using the given seed
+   * @param count the number of examples to print
+   * @param seed seed for the PRNG
+   */
+  default void printExamples(int count, long seed) {
+    examples(count, seed).stream().map(this::asString).forEach(System.out::println);
+  }
+
+  /**
+   * Generates a single example using this generator
+   * @return an example
+   */
+  default T example() {
+    return generate(new SimpleRandomnessSource(Configuration.defaultPRNG(System.nanoTime()), 100));
+  }
+
+  /**
+   * Generates a list of examples using this generator. If count is > 3 then the boundaries of the generator will be
+   * generated first, followed by randomly generated data.
+   * @param count the number of examples to generate
+   * @return a list of generated examples
+   */
+  default List<T> examples(int count) {
+    return examples(count, System.nanoTime());
+  }
+
+  /**
+   * Generates a list of examples using this generator and the given seed. If count is > 3 then the boundaries of the
+   * generator will be generated first, followed by randomly generated data.
+   * @param count the number of examples to generate
+   * @param seed seed for the PRNG
+   * @return a list of generated examples
+   */
+  default List<T> examples(int count, long seed) {
+    List<T> r = new ArrayList<>(count);
+    if (count <= 3) {
+      for (int i = 0; i < count; i++) {
+        r.add(example());
+      }
+    } else {
+      Distribution<T> randomDistribution = new BoundarySkewedDistribution<>(
+              Configuration.systemStrategy().withFixedSeed(seed),
+              this);
+
+      for (int i = 0; i < count; i++) {
+        r.add(randomDistribution.generate().value());
+      }
+    }
+
+    return r;
+  }
+
   /**
    * Maps generated values with supplied function consuming one value
    * @param <R> Type to map to

core/src/main/java/org/quicktheories/impl/BoundarySkewedDistribution.java

@@ -11,15 +11,15 @@
  *
  * @param <T>
  */
-class BoundarySkewedDistribution<T> implements Distribution<T> {
+public class BoundarySkewedDistribution<T> implements Distribution<T> {
 
   private ArrayDeque<long[]> toVisit;
 
   private final Gen<T> gen;
   private final Strategy config;
 
 
-  BoundarySkewedDistribution(Strategy config, Gen<T> gen) {
+  public BoundarySkewedDistribution(Strategy config, Gen<T> gen) {
     this.gen = gen;
     this.config = config;
     toVisit = findBoundaries(config, gen);   

core/src/main/java/org/quicktheories/impl/PrecursorDataPair.java

@@ -1,6 +1,6 @@
 package org.quicktheories.impl;
 
-class PrecursorDataPair<T> {
+public class PrecursorDataPair<T> {
   private final Precursor precursor;
   private final T value;
   private final int failedAssumptions;
@@ -15,7 +15,7 @@ Precursor precursor() {
     return precursor;
   }
 
-  T value() {
+  public T value() {
     return value;
   }