Add Either.toTry(L => Throwable)

Author: evantill

src/main/java/io/vavr/control/Either.java

@@ -794,6 +794,22 @@ public final Validation<L, R> toValidation() {
         return isRight() ? Validation.valid(get()) : Validation.invalid(getLeft());
     }
 
+    /**
+     * Transforms this {@code Either} into a {@link Try} instance.
+     * <p>
+     * Map this {@code left} value to a {@link Throwable} using the {@code leftMapper}
+     * or return a {@link Try#success(Object) Success} of this {@code right} value.
+     * </p>
+     *
+     * @param leftMapper A function that maps the left value of this {@code Either} to a {@link Throwable} instance
+     * @return A {@link Try} instance that represents the result of the transformation
+     * @throws NullPointerException if {@code leftMapper} is {@code null}
+     */
+    public final Try<R> toTry(Function<? super L, ? extends Throwable> leftMapper) {
+        Objects.requireNonNull(leftMapper, "leftMapper is null");
+        return mapLeft(leftMapper).fold(Try::failure,Try::success);
+    }
+
     // -- Left/Right projections
 
     /**

src/test/java/io/vavr/control/EitherTest.java

@@ -571,6 +571,22 @@ public void shouldConvertToInvalidValidation() {
         assertThat(validation.getError()).isEqualTo("vavr");
     }
 
+    // -- toTry
+
+    @Test
+    public void shouldConvertToSuccessTry() {
+        final Try<Integer> actual = Either.right(42).toTry(left -> new IllegalStateException(Objects.toString(left)));
+        assertThat(actual.isSuccess()).isTrue();
+        assertThat(actual.get()).isEqualTo(42);
+    }
+
+    @Test
+    public void shouldConvertToFailureTry() {
+        final Try<?> actual = Either.left("vavr").toTry(left->new IllegalStateException(left));
+        assertThat(actual.isFailure()).isTrue();
+        assertThat(actual.getCause().getMessage()).isEqualTo("vavr");
+    }
+
     // hashCode
 
     @Test