implement issue #28 : add support to use java 8 Suppliers as Randomizers

random-beans/src/main/java/io/github/benas/randombeans/EnhancedRandomBuilder.java

@@ -31,7 +31,9 @@
 import io.github.benas.randombeans.randomizers.registry.CustomRandomizerRegistry;
 
 import java.util.*;
+import java.util.function.Supplier;
 
+import static io.github.benas.randombeans.RandomizerProxy.asRandomizer;
 import static io.github.benas.randombeans.util.Constants.DEFAULT_SEED;
 
 /**
@@ -77,6 +79,18 @@ public <T, F, R> EnhancedRandomBuilder randomize(FieldDefinition<T, F> fieldDefi
  return this;
  }
 
+ /**
+ * Register a supplier as randomizer for a given field.
+ *
+ * @param fieldDefinition definition of the field to randomize
+ * @param supplier the custom {@link Supplier} to use
+ * @return a pre configured {@link EnhancedRandomBuilder} instance
+ */
+ public <T, F, R> EnhancedRandomBuilder randomize(FieldDefinition<T, F> fieldDefinition, Supplier<R> supplier) {
+ customRandomizerRegistry.registerRandomizer(fieldDefinition.getName(), fieldDefinition.getType(), fieldDefinition.getClazz(), asRandomizer(supplier));
+ return this;
+ }
+
  /**
  * Register a custom randomizer for a given type.
  *
@@ -89,6 +103,18 @@ public <T, R> EnhancedRandomBuilder randomize(Class<T> type, Randomizer<R> rando
  return this;
  }
 
+ /**
+ * Register a supplier as randomizer for a given type.
+ *
+ * @param type class of the type to randomize
+ * @param supplier the custom {@link Supplier} to use
+ * @return a pre configured {@link EnhancedRandomBuilder} instance
+ */
+ public <T, R> EnhancedRandomBuilder randomize(Class<T> type, Supplier<R> supplier) {
+ customRandomizerRegistry.registerRandomizer(type, asRandomizer(supplier));
+ return this;
+ }
+
  /**
  * Exclude a field from being populated.
  *

random-beans/src/main/java/io/github/benas/randombeans/RandomizerProxy.java

@@ -0,0 +1,42 @@
+package io.github.benas.randombeans;
+
+import io.github.benas.randombeans.api.Randomizer;
+
+import java.lang.reflect.InvocationHandler;
+import java.lang.reflect.Method;
+import java.lang.reflect.Proxy;
+import java.util.function.Supplier;
+
+/**
+ * Dynamic proxy that adapts a {@link java.util.function.Supplier} to a {@link Randomizer}.
+ *
+ * @author Mahmoud Ben Hassine (mahmoud.benhassine@icloud.com)
+ */
+class RandomizerProxy implements InvocationHandler {
+
+ private Supplier<?> target;
+
+ RandomizerProxy(final Supplier<?> target) {
+ this.target = target;
+ }
+
+ /**
+ * Create a dynamic proxy that adapts the given {@link Supplier} to a {@link Randomizer}.
+ * @param supplier to adapt
+ * @return the proxy randomizer
+ */
+ static Randomizer<?> asRandomizer(final Supplier<?> supplier) {
+ return (Randomizer<?>) Proxy.newProxyInstance(
+ Randomizer.class.getClassLoader(),
+ new Class[]{Randomizer.class},
+ new RandomizerProxy(supplier));
+ }
+
+ @Override
+ public Object invoke(final Object proxy, final Method method, final Object[] args) throws Throwable {
+ if ("getRandomValue".equals(method.getName())) {
+ return target.getClass().getMethod("get").invoke(target, args);
+ }
+ return null;
+ }
+}

random-beans/src/test/java/io/github/benas/randombeans/EnhancedRandomImplTest.java

@@ -30,6 +30,7 @@
 import io.github.benas.randombeans.beans.*;
 import io.github.benas.randombeans.randomizers.misc.ConstantRandomizer;
 
+import org.assertj.core.api.Assertions;
 import org.junit.Before;
 import org.junit.Test;
 import org.junit.runner.RunWith;
@@ -38,6 +39,7 @@
 
 import java.util.Date;
 import java.util.List;
+import java.util.function.Supplier;
 
 import static io.github.benas.randombeans.EnhancedRandomBuilder.aNewEnhancedRandomBuilder;
 import static io.github.benas.randombeans.FieldDefinitionBuilder.field;
@@ -49,18 +51,22 @@
 @RunWith(MockitoJUnitRunner.class)
 public class EnhancedRandomImplTest {
 
- private static final String NAME = "foo";
+ private static final String FOO = "foo";
  private static final long SEED = 123L;
 
  @Mock
  private Randomizer<String> randomizer;
 
+ @Mock
+ private Supplier<String> supplier;
+
  private EnhancedRandom enhancedRandom;
 
  @Before
  public void setUp() {
  enhancedRandom = aNewEnhancedRandomBuilder().build();
- when(randomizer.getRandomValue()).thenReturn(NAME);
+ when(randomizer.getRandomValue()).thenReturn(FOO);
+ when(supplier.get()).thenReturn(FOO);
  }
 
  @Test
@@ -131,7 +137,7 @@ public void generatedBeansWithCustomRandomizersShouldBeCorrectlyPopulated() {
  Person person = enhancedRandom.nextObject(Person.class);
 
  assertThat(person).isNotNull();
- assertThat(person.getName()).isEqualTo(NAME);
+ assertThat(person.getName()).isEqualTo(FOO);
  }
 
  @Test
@@ -255,6 +261,23 @@ public void generatedObjectShouldBeAlwaysTheSameForTheSameSeed() {
  assertThat(actualInts).isEqualTo(expectedInts);
  }
 
+ @Test
+ public void supplierShouldBehaveLikeRandomizer() throws Exception {
+ // Given
+ enhancedRandom = aNewEnhancedRandomBuilder().randomize(String.class, supplier).build(); // All string fields should be equal to FOO
+
+ // When
+ Person actual = enhancedRandom.nextObject(Person.class);
+
+ // Then
+ assertThat(actual).isNotNull();
+ assertThat(actual.getPhoneNumber()).isEqualTo(FOO);
+ assertThat(actual.getName()).isEqualTo(FOO);
+ assertThat(actual.getEmail()).isEqualTo(FOO);
+ assertThat(actual.getEmail()).isEqualTo(FOO);
+ assertThat(actual.getExcluded()).isNull();
+ }
+
 
  private Person buildExpectedPerson() {
  Person expectedPerson = new Person();

random-beans/src/test/java/io/github/benas/randombeans/RandomizerProxyTest.java

@@ -0,0 +1,34 @@
+package io.github.benas.randombeans;
+
+import io.github.benas.randombeans.api.Randomizer;
+import org.junit.Test;
+
+import java.util.function.Supplier;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+public class RandomizerProxyTest {
+
+ public static final String FOO = "foo";
+
+ @Test
+ public void theRandomizerProxyShouldBehaveLikeTheSupplier() throws Exception {
+ // Given
+ MySupplier supplier = new MySupplier();
+
+ // When
+ Randomizer<?> randomizer = RandomizerProxy.asRandomizer(supplier);
+
+ // Then
+ assertThat(randomizer.getRandomValue()).isInstanceOf(String.class).isEqualTo(FOO);
+ }
+
+ class MySupplier implements Supplier<String> {
+
+ @Override
+ public String get() {
+ return FOO;
+ }
+
+ }
+}