add missing map method

2 files changed, 21 insertions, 5 deletions

diff --git a/src/main/java/org/pacien/lemonad/attempt/Attempt.java b/src/main/java/org/pacien/lemonad/attempt/Attempt.java
index e36ac4b..9f5befa 100644
--- a/src/main/java/org/pacien/lemonad/attempt/Attempt.java
+++ b/src/main/java/org/pacien/lemonad/attempt/Attempt.java
@@ -90,6 +90,17 @@ public interface Attempt<R, E> {
   }
 
   /**
+   * @param resultMapper a function producing an {@link Attempt}, called with the current result if this {@link Attempt} is a success.
+   * @param errorMapper  a function producing an {@link Attempt}, called with the current error if this {@link Attempt} is a failure.
+   * @return the transformed {@link Attempt}.
+   */
+  default <RR, EE> Attempt<RR, EE> map(@NonNull Function<? super R, ? extends Attempt<? extends RR, ? extends EE>> resultMapper,
+                                       @NonNull Function<? super E, ? extends Attempt<? extends RR, ? extends EE>> errorMapper) {
+    //noinspection unchecked
+    return (Attempt<RR, EE>) (isSuccess() ? resultMapper.apply(getResult()) : errorMapper.apply(getError()));
+  }
+
+  /**
    * @param mapper a function transforming an {@link Attempt}.
    * @return the transformed {@link Attempt}
    */
diff --git a/src/test/java/org/pacien/lemonad/attempt/AttemptTest.java b/src/test/java/org/pacien/lemonad/attempt/AttemptTest.java
index 6d87335..bb367dc 100644
--- a/src/test/java/org/pacien/lemonad/attempt/AttemptTest.java
+++ b/src/test/java/org/pacien/lemonad/attempt/AttemptTest.java
@@ -81,10 +81,12 @@ class AttemptTest {
   @Test void testTransformationFlow() {
     var result0 = 0;
     var result1 = "res";
-    var result2 = 0L;
-    var fault0 = 0;
-    var fault1 = 1;
-    var fault2 = 2;
+    var result2 = true;
+    var result3 = 0L;
+    var fault0 = 0L;
+    var fault1 = 0;
+    var fault2 = "fail";
+    var fault3 = false;
 
     Attempt.success(result0)
            .mapError(__ -> fail())
@@ -109,6 +111,9 @@ class AttemptTest {
              return Attempt.failure(fault2);
            })
            .ifSuccess(__ -> fail())
-           .ifFailure(f -> assertEquals(fault2, f));
+           .ifFailure(f -> assertEquals(fault2, f))
+           .map(__ -> Attempt.failure(fault3), __ -> Attempt.success(result3))
+           .ifSuccess(result -> assertEquals(result3, result))
+           .ifFailure(__ -> fail());
   }
 }