Merge branch 'topicusoverheid-feature/random-collection-element'

src/main/java/com/github/javafaker/service/RandomService.java

@@ -1,5 +1,6 @@
 package com.github.javafaker.service;
 
+import java.util.List;
 import java.util.Random;
 
 public class RandomService {
@@ -50,4 +51,37 @@ public class RandomService {
     public Boolean nextBoolean() {
         return random.nextBoolean();
     }
+
+    /**
+     * Returns a random element from an array.
+     *
+     * @param array The array to take a random element fom.
+     * @param <E>   The type of the elements in the array.
+     * @return A randomly selected element from the array.
+     */
+    public <E> E nextElement(E[] array) {
+        return array[this.nextInt(array.length)];
+    }
+
+    /**
+     * Returns a random element from a list.
+     *
+     * @param list The list to take a random element fom.
+     * @param <E>  The type of the elements in the list.
+     * @return A randomly selected element from the list.
+     */
+    public <E> E nextElement(List<E> list) {
+        return list.get(this.nextInt(list.size()));
+    }
+
+    /**
+     * Returns a random enumeration value
+     *
+     * @param enumeration The enumeration to take a random value from
+     * @param <E>         The type of the enumeration
+     * @return A randomly selected enumeration value
+     */
+    public <E extends Enum<E>> E nextEnumValue(Class<E> enumeration) {
+        return nextElement(enumeration.getEnumConstants());
+    }
 }

src/test/java/com/github/javafaker/service/RandomServiceTest.java

@@ -1,16 +1,17 @@
 package com.github.javafaker.service;
 
 import com.github.javafaker.AbstractFakerTest;
+import java.util.Arrays;
+import java.util.Collection;
+import java.util.List;
+import java.util.Random;
 import org.junit.Test;
 import org.junit.runner.RunWith;
 import org.junit.runners.Parameterized;
 
-import java.util.Arrays;
-import java.util.Collection;
-import java.util.Random;
-
 import static org.hamcrest.CoreMatchers.is;
 import static org.hamcrest.Matchers.greaterThan;
+import static org.hamcrest.Matchers.isIn;
 import static org.hamcrest.Matchers.lessThan;
 import static org.junit.Assert.assertThat;
 
@@ -55,4 +56,35 @@ public class RandomServiceTest extends AbstractFakerTest {
         assertThat(randomService.nextLong(Long.MAX_VALUE), greaterThan(0L));
         assertThat(randomService.nextLong(Long.MAX_VALUE), lessThan(Long.MAX_VALUE));
     }
+
+    @Test
+    public void testNextArrayElement() {
+        Integer[] array = new Integer[] { 1, 2, 3, 5, 8, 13, 21 };
+
+        for (int i = 1; i < 10; i++) {
+            assertThat(randomService.nextElement(array), isIn(array));
+        }
+    }
+
+    @Test
+    public void testNextListElement() {
+        List<Integer> list = Arrays.asList(new Integer[] { 1, 2, 3, 5, 8, 13, 21 });
+
+        for (int i = 1; i < 10; i++) {
+            assertThat(randomService.nextElement(list), isIn(list));
+        }
+    }
+
+    @Test
+    public void testNextEnumValue() {
+        for (int i = 1; i < 10; i++) {
+            assertThat(randomService.nextEnumValue(TestEnum.class), isIn(TestEnum.values()));
+        }
+    }
+
+    private enum TestEnum {
+        ONE,
+        TWO,
+        THREE
+    }
 }