Add an ObjectGenerator<>, and related machinery (also a mapOf generator)

1 files changed, 29 insertions, 0 deletions

diff --git a/src/main/java/au/id/zancanaro/javacheck/Generators.java b/src/main/java/au/id/zancanaro/javacheck/Generators.java
index f4ac025..63d4ece 100644
--- a/src/main/java/au/id/zancanaro/javacheck/Generators.java
+++ b/src/main/java/au/id/zancanaro/javacheck/Generators.java
@@ -1,8 +1,12 @@
 package au.id.zancanaro.javacheck;
 
+import au.id.zancanaro.javacheck.object.GeneratorProvider;
+import au.id.zancanaro.javacheck.object.ObjectGenerator;
+
 import java.util.*;
 import java.util.function.Consumer;
 import java.util.function.Function;
+import java.util.stream.Collectors;
 import java.util.stream.Stream;
 import java.util.stream.StreamSupport;
 
@@ -75,6 +79,7 @@ public final class Generators {
     private static ShrinkStrategy<Long> longShrinkStrategy(final long bound) {
         return value -> StreamSupport.stream(new Spliterators.AbstractSpliterator<Long>(Long.MAX_VALUE, Spliterator.ORDERED) {
             long curr = value - bound;
+
             @Override
             public boolean tryAdvance(Consumer<? super Long> action) {
                 if (curr == 0) {
@@ -173,6 +178,22 @@ public final class Generators {
         };
     }
 
+    @SuppressWarnings("unchecked")
+    public static <K, V> Generator<Map<K, V>> mapOf(Generator<K> keyGen, Generator<V> valueGen) {
+        return (random, size) -> {
+            Generator<Integer> countGen = sized(s -> integer(0, s));
+            int count = countGen.generate(random, size).getValue();
+            return Generator.list(count, Generator.tuple(keyGen, valueGen))
+                    .generate(random, size)
+                    .map(pairs -> pairs.stream()
+                            .collect(Collectors.toMap(
+                                    pair -> (K) pair.get(0),
+                                    pair -> (V) pair.get(1),
+                                    (first, second) -> second)))
+                    .map(Collections::unmodifiableMap);
+        };
+    }
+
     public static Generator<Character> character() {
         return integer(0, 256).map(i -> (char) i.intValue());
     }
@@ -216,4 +237,12 @@ public final class Generators {
             return String.valueOf(chars);
         });
     }
+
+    public static <T> Generator<T> ofType(Class<T> type) {
+        return new ObjectGenerator<>(type);
+    }
+
+    public static <T> Generator<T> ofType(Class<T> type, GeneratorProvider provider) {
+        return new ObjectGenerator<>(type, provider);
+    }
 }