From dcf1847def64e50207d002c06d63f8a6f48644de Mon Sep 17 00:00:00 2001
From: Paul Campbell <pcampbell@kemitix.net>
Date: Sat, 22 Apr 2017 07:34:44 +0100
Subject: [PATCH] Condition: remove use of 'if' internaly

By using a look-up map for true and false the only branch in the code
is removed.
---
 .../net/kemitix/conditional/Condition.java    | 60 ++++++++-----------
 1 file changed, 24 insertions(+), 36 deletions(-)

diff --git a/src/main/java/net/kemitix/conditional/Condition.java b/src/main/java/net/kemitix/conditional/Condition.java
index 7a5f313..842c98c 100644
--- a/src/main/java/net/kemitix/conditional/Condition.java
+++ b/src/main/java/net/kemitix/conditional/Condition.java
@@ -21,8 +21,11 @@
 
 package net.kemitix.conditional;
 
-import lombok.AccessLevel;
-import lombok.NoArgsConstructor;
+import java.util.AbstractMap.SimpleEntry;
+import java.util.Collections;
+import java.util.Map;
+import java.util.stream.Collectors;
+import java.util.stream.Stream;
 
 /**
  * If-then-else in a functional-style.
@@ -31,6 +34,14 @@ import lombok.NoArgsConstructor;
  */
 public interface Condition {
 
+    Condition TRUE = new TrueCondition();
+
+    Condition FALSE = new FalseCondition();
+
+    Map<Boolean, Condition> CONDITIONS = Collections.unmodifiableMap(
+            Stream.of(new SimpleEntry<>(true, TRUE), new SimpleEntry<>(false, FALSE))
+                  .collect(Collectors.toMap(Map.Entry::getKey, Map.Entry::getValue)));
+
     /**
      * Create a new {@code Condition} for the clause.
      *
@@ -39,10 +50,7 @@ public interface Condition {
      * @return the Condition
      */
     static Condition where(final boolean clause) {
-        if (clause) {
-            return TrueCondition.getInstance();
-        }
-        return FalseCondition.getInstance();
+        return CONDITIONS.get(clause);
     }
 
     /**
@@ -52,7 +60,7 @@ public interface Condition {
      *
      * @return the Condition
      */
-    static Condition whereNot(boolean clause) {
+    static Condition whereNot(final boolean clause) {
         return where(!clause);
     }
 
@@ -72,7 +80,7 @@ public interface Condition {
      *
      * @return the Condition
      */
-    default Condition andNot(boolean clause) {
+    default Condition andNot(final boolean clause) {
         return and(!clause);
     }
 
@@ -92,7 +100,7 @@ public interface Condition {
      *
      * @return the Condition
      */
-    default Condition orNot(boolean clause) {
+    default Condition orNot(final boolean clause) {
         return or(!clause);
     }
 
@@ -119,39 +127,29 @@ public interface Condition {
      *
      * @return the Condition
      */
-    default Condition otherwise(boolean clause) {
+    default Condition otherwise(final boolean clause) {
         return where(clause);
     }
 
     /**
      * A {@code Condition} that has evaluated to {@code true}.
      */
-    @NoArgsConstructor(access = AccessLevel.PRIVATE)
     class TrueCondition implements Condition {
 
-        private static final Condition INSTANCE = new TrueCondition();
-
-        private static Condition getInstance() {
-            return INSTANCE;
-        }
-
         @Override
         public Condition and(final boolean clause) {
-            if (clause) {
-                return this;
-            }
-            return FalseCondition.getInstance();
+            return where(clause);
         }
 
         @Override
         public Condition or(final boolean secondClause) {
-            return this;
+            return TRUE;
         }
 
         @Override
         public Condition then(final Runnable response) {
             response.run();
-            return this;
+            return TRUE;
         }
 
         @Override
@@ -163,31 +161,21 @@ public interface Condition {
     /**
      * A {@code Condition} that has evaluated to {@code false}.
      */
-    @NoArgsConstructor(access = AccessLevel.PRIVATE)
     class FalseCondition implements Condition {
 
-        private static final Condition INSTANCE = new FalseCondition();
-
-        private static Condition getInstance() {
-            return INSTANCE;
-        }
-
         @Override
         public Condition and(final boolean clause) {
-            return this;
+            return FALSE;
         }
 
         @Override
         public Condition or(final boolean secondClause) {
-            if (secondClause) {
-                return TrueCondition.getInstance();
-            }
-            return this;
+            return where(secondClause);
         }
 
         @Override
         public Condition then(final Runnable response) {
-            return this;
+            return FALSE;
         }
 
         @Override