Merge pull request #102 from alexengrig/optional-of-nullable

Optional of nullable value
Fix #99

Author: alexengrig

CHANGES.md

@@ -3,6 +3,7 @@
 ## 0.4.0
 
 *   [[#101](../../issues/101)] Create left, right, center, compose and pipe of FunctionX
+*   [[#88](../../issues/88)] Create OptionalX#of for nullable object
 
 ## 0.3.0
 

src/main/java/io/github/alexengrig/lambdax/OptionalX.java

@@ -25,7 +25,7 @@
  * This utility class contains useful lambdas for {@link java.util.Optional}.
  *
  * @author Grig Alex
- * @version 0.1.1
+ * @version 0.4.0
  * @see java.util.Optional
  * @see java.util.function.Consumer
  * @see java.util.function.Supplier
@@ -36,6 +36,19 @@ public final class OptionalX {
     private OptionalX() {
     }
 
+    /**
+     * Returns an {@link java.util.Optional} describing the value.
+     *
+     * @param value a value is passed as the argument to {@link java.util.Optional#ofNullable(Object)}
+     * @param <T>   a type of {@link java.util.Optional} value
+     * @return an {@link java.util.Optional} with the value
+     * @see java.util.Optional#ofNullable(Object)
+     * @since 0.4.0
+     */
+    public static <T> Optional<T> of(T value) {
+        return Optional.ofNullable(value);
+    }
+
     /**
      * <p>Returns an {@link java.util.Optional} describing the given value
      * from {@link java.util.function.Supplier}.</p>
@@ -56,8 +69,8 @@ public static <T> Optional<T> of(Supplier<? extends T> generator) {
     }
 
     /**
-     * <p>Returns an {@link java.util.function.UnaryOperator}
-     * that execute the action ({@link java.util.function.Consumer}) for a value and return it.</p>
+     * Returns an {@link java.util.function.UnaryOperator}
+     * that execute the action ({@link java.util.function.Consumer}) for a value and return it.
      *
      * @param action a {@link java.util.function.Consumer} that execute an action on a value
      * @param <T>    a type of the operand and result of the operator

src/test/java/io/github/alexengrig/lambdax/OptionalXTest.java

@@ -20,11 +20,37 @@
 import org.junit.Test;
 
 import java.util.ArrayDeque;
+import java.util.ArrayList;
 import java.util.Deque;
+import java.util.function.Supplier;
 
-import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.*;
 
 public class OptionalXTest {
+    @Test
+    public void checkOfValue() {
+        Object o = new Object();
+        assertTrue(OptionalX.of(o).isPresent());
+        o = null;
+        //noinspection ConstantConditions
+        assertFalse(OptionalX.of(o).isPresent());
+    }
+
+    @Test
+    public void checkOfSupplier() {
+        final Supplier<Object> o = Object::new;
+        assertTrue(OptionalX.of(o).isPresent());
+    }
+
+    @Test
+    public void checkPeek() {
+        final Object expect = new Object();
+        final ArrayList<Object> list = new ArrayList<>();
+        final Object actual = OptionalX.peek(list::add).apply(expect);
+        assertEquals(expect, actual);
+        assertTrue(list.contains(expect));
+    }
+
     @Test
     public void checkOfAndPeek() {
         int value = 1;
@@ -34,5 +60,4 @@ public void checkOfAndPeek() {
                 .orElseThrow(IllegalStateException::new);
         assertEquals(value, actual);
     }
-
 }