From 29232d4e714ef49206f32dae44fd13d32d2e540b Mon Sep 17 00:00:00 2001
From: Paul Campbell <pcampbell@kemitix.net>
Date: Fri, 21 Apr 2017 14:28:54 +0100
Subject: [PATCH] Condition: overload otherwise to allow if-then-else-if
 behaviour

---
 README.adoc                                   | 19 +++++++++++++
 .../net/kemitix/conditional/Condition.java    | 11 ++++++++
 .../kemitix/conditional/ConditionalTest.java  | 27 +++++++++++++++++++
 3 files changed, 57 insertions(+)

diff --git a/README.adoc b/README.adoc
index 45a63d9..e26b30f 100644
--- a/README.adoc
+++ b/README.adoc
@@ -131,6 +131,25 @@ Condition.where(isFalse())
          .otherwise(() -> doSomethingElse());
 ----
 
+### if-then-else-if
+
+[[source,java]]
+----
+if (isFalse()) {
+    doSomething();
+} else if (isTrue()) {
+    doSomethingElse();
+}
+----
+
+[[source,java]]
+----
+Condition.where(isFalse())
+         .then(() -> doSomething())
+         .otherwise(isTrue)
+         .then(() -> doSomethingElse());
+----
+
 ### if-then-if-then
 
 [[source,java]]
diff --git a/src/main/java/net/kemitix/conditional/Condition.java b/src/main/java/net/kemitix/conditional/Condition.java
index 6213b62..4df41e0 100644
--- a/src/main/java/net/kemitix/conditional/Condition.java
+++ b/src/main/java/net/kemitix/conditional/Condition.java
@@ -109,6 +109,17 @@ public interface Condition {
      */
     void otherwise(Runnable response);
 
+    /**
+     * Create a new {@code Condition} for the clause as a continuation to an existing {@code Condition}.
+     *
+     * @param clause the condition to test
+     *
+     * @return the Condition
+     */
+    default Condition otherwise(boolean clause) {
+        return where(clause);
+    }
+
     /**
      * A {@code Condition} that has evaluated to {@code true}.
      */
diff --git a/src/test/java/net/kemitix/conditional/ConditionalTest.java b/src/test/java/net/kemitix/conditional/ConditionalTest.java
index 87209cc..67c52a1 100644
--- a/src/test/java/net/kemitix/conditional/ConditionalTest.java
+++ b/src/test/java/net/kemitix/conditional/ConditionalTest.java
@@ -144,6 +144,28 @@ public class ConditionalTest {
         thenTheThenResponseRuns();
     }
 
+    @Test
+    public void whereFalseElseTrueThenOtherwiseRuns() {
+        //when
+        Condition.where(false)
+                 .then(thenResponse)
+                 .otherwise(true)
+                 .then(otherwiseResponse);
+        //then
+        thenTheOtherwiseResponseRuns();
+    }
+
+    @Test
+    public void whereFalseElseFalseThenNothingRuns() {
+        //when
+        Condition.where(false)
+                 .then(thenResponse)
+                 .otherwise(false)
+                 .then(otherwiseResponse);
+        //then
+        thenNoResponseRuns();
+    }
+
     private void whenOr(final boolean firstClause, final boolean secondClause) {
         Condition.where(firstClause)
                  .or(secondClause)
@@ -172,6 +194,11 @@ public class ConditionalTest {
         assertThat(otherwiseFlag).isTrue();
     }
 
+    private void thenNoResponseRuns() {
+        assertThat(thenFlag).isFalse();
+        assertThat(otherwiseFlag).isFalse();
+    }
+
     private void when(final boolean firstClause, final boolean secondClause) {
         Condition.where(firstClause)
                  .and(secondClause)