From d1f4c61f00d2ab1f22b9aac32f1db77812864bbe Mon Sep 17 00:00:00 2001
From: Paul Campbell <pcampbell@kemitix.net>
Date: Thu, 19 Aug 2021 11:35:05 +0100
Subject: [PATCH] Result.onSuccess should return Result/ResultVoid (#224)

* Version set to 3.2.0

* Result{Void}.onSuccess() now returns a Result<T>/ResultVoid
---
 pom.xml                                       |  2 +-
 src/main/java/net/kemitix/mon/result/Err.java |  4 +-
 .../java/net/kemitix/mon/result/ErrVoid.java  |  4 +-
 .../java/net/kemitix/mon/result/Result.java   |  3 +-
 .../net/kemitix/mon/result/ResultVoid.java    |  3 +-
 .../java/net/kemitix/mon/result/Success.java  |  3 +-
 .../net/kemitix/mon/result/SuccessVoid.java   |  3 +-
 src/test/java/net/kemitix/mon/ResultTest.java | 46 +++++++++++++++++++
 8 files changed, 59 insertions(+), 9 deletions(-)

diff --git a/pom.xml b/pom.xml
index b1b9c28..e5857a4 100644
--- a/pom.xml
+++ b/pom.xml
@@ -11,7 +11,7 @@
     </parent>
 
     <artifactId>mon</artifactId>
-    <version>3.1.0</version>
+    <version>3.2.0</version>
 
     <name>Mon</name>
     <description>Wrapper, TypeAlias, Maybe, Result, Tree, Lazy, Either and Combinators for Java.
diff --git a/src/main/java/net/kemitix/mon/result/Err.java b/src/main/java/net/kemitix/mon/result/Err.java
index 6082cb8..0f9ec45 100644
--- a/src/main/java/net/kemitix/mon/result/Err.java
+++ b/src/main/java/net/kemitix/mon/result/Err.java
@@ -101,8 +101,8 @@ class Err<T> implements Result<T> {
     }
 
     @Override
-    public void onSuccess(final Consumer<T> successConsumer) {
-        // do nothing
+    public Result<T> onSuccess(final Consumer<T> successConsumer) {
+        return this;
     }
 
     @Override
diff --git a/src/main/java/net/kemitix/mon/result/ErrVoid.java b/src/main/java/net/kemitix/mon/result/ErrVoid.java
index edb3f76..fd2da27 100644
--- a/src/main/java/net/kemitix/mon/result/ErrVoid.java
+++ b/src/main/java/net/kemitix/mon/result/ErrVoid.java
@@ -39,8 +39,8 @@ public class ErrVoid implements ResultVoid {
     }
 
     @Override
-    public void onSuccess(final Runnable runnable) {
-        // do nothing
+    public ResultVoid onSuccess(final Runnable runnable) {
+        return this;
     }
 
     @Override
diff --git a/src/main/java/net/kemitix/mon/result/Result.java b/src/main/java/net/kemitix/mon/result/Result.java
index 20563a2..f1111ed 100644
--- a/src/main/java/net/kemitix/mon/result/Result.java
+++ b/src/main/java/net/kemitix/mon/result/Result.java
@@ -707,9 +707,10 @@ public interface Result<T> extends BaseResult, ThrowableFunctor<T, ThrowableFunc
      * success value. When this is an error, then nothing happens.</p>
      *
      * @param successConsumer the consumer to handle the success
+     * @return the original Result
      */
     @API(status = STABLE)
-    void onSuccess(Consumer<T> successConsumer);
+    Result<T> onSuccess(Consumer<T> successConsumer);
 
     /**
      * A handler for error state, when the error matches the errorClass.
diff --git a/src/main/java/net/kemitix/mon/result/ResultVoid.java b/src/main/java/net/kemitix/mon/result/ResultVoid.java
index 74c9e43..0bf9259 100644
--- a/src/main/java/net/kemitix/mon/result/ResultVoid.java
+++ b/src/main/java/net/kemitix/mon/result/ResultVoid.java
@@ -66,9 +66,10 @@ public interface ResultVoid extends BaseResult {
      * success value. When this is an error, then nothing happens.</p>
      *
      * @param runnable the call if the Result is a success
+     * @return the original ResultVoid
      */
     @API(status = STABLE)
-    void onSuccess(Runnable runnable);
+    ResultVoid onSuccess(Runnable runnable);
 
     /**
      * A handler for error state, when the error matches the errorClass.
diff --git a/src/main/java/net/kemitix/mon/result/Success.java b/src/main/java/net/kemitix/mon/result/Success.java
index 89a8c03..03d9096 100644
--- a/src/main/java/net/kemitix/mon/result/Success.java
+++ b/src/main/java/net/kemitix/mon/result/Success.java
@@ -93,8 +93,9 @@ class Success<T> implements Result<T> {
     }
 
     @Override
-    public void onSuccess(final Consumer<T> successConsumer) {
+    public Result<T> onSuccess(final Consumer<T> successConsumer) {
         successConsumer.accept(value);
+        return this;
     }
 
     @Override
diff --git a/src/main/java/net/kemitix/mon/result/SuccessVoid.java b/src/main/java/net/kemitix/mon/result/SuccessVoid.java
index 5b70d64..11b9598 100644
--- a/src/main/java/net/kemitix/mon/result/SuccessVoid.java
+++ b/src/main/java/net/kemitix/mon/result/SuccessVoid.java
@@ -47,8 +47,9 @@ public class SuccessVoid implements ResultVoid {
     }
 
     @Override
-    public void onSuccess(final Runnable runnable) {
+    public ResultVoid onSuccess(final Runnable runnable) {
         runnable.run();
+        return this;
     }
 
     @Override
diff --git a/src/test/java/net/kemitix/mon/ResultTest.java b/src/test/java/net/kemitix/mon/ResultTest.java
index 0b92742..ba4f4c1 100644
--- a/src/test/java/net/kemitix/mon/ResultTest.java
+++ b/src/test/java/net/kemitix/mon/ResultTest.java
@@ -832,6 +832,52 @@ class ResultTest implements WithAssertions {
             //then
             assertThat(capture).hasValue(1);
         }
+
+        @Test
+        void error_whenOnSuccess_returnsSelf() {
+            //given
+            final Result<Integer> error = anError(new RuntimeException());
+
+            //when
+            final Result<Integer> result = error.onSuccess(x -> {});
+
+            //then
+            assertThat(result).isSameAs(error);
+        }
+
+        @Test
+        void success_whenOnSuccess_returnsSelf() {
+            //given
+            final Result<Integer> ok = Result.ok(1);
+
+            //when
+            final Result<Integer> result = ok.onSuccess(x -> {});
+
+            //then
+            assertThat(result).isSameAs(ok);
+        }
+
+        @Test void errorVoid_whenOnSuccess_returnsSelf() {
+            //given
+            final ResultVoid error = Result.error(new RuntimeException());
+
+            //when
+            final ResultVoid result = error.onSuccess(() -> {});
+
+            //then
+            assertThat(result).isSameAs(error);
+        }
+
+        @Test void successVoid_whenOnSuccess_returnsSelf() {
+            //given
+            final ResultVoid ok = Result.ok();
+
+            //when
+            final ResultVoid result = ok.onSuccess(() -> {});
+
+            //then
+            assertThat(result).isSameAs(ok);
+        }
     }
 
     @Nested