From 09d78604ac4269e71609e5b39aa8cc7baf3b1b06 Mon Sep 17 00:00:00 2001
From: Pontus Melke <pontus.melke@neotechnology.com>
Date: Mon, 18 Jan 2016 22:34:20 +0100
Subject: [PATCH] Support for ternary operator

---
 .../bytecode/ByteCodeExpressionVisitor.java   | 10 ++-
 .../org/neo4j/codegen/CodeGenerationTest.java | 61 ++++++++++++++++++-
 2 files changed, 67 insertions(+), 4 deletions(-)

diff --git a/community/codegen/src/main/java/org/neo4j/codegen/bytecode/ByteCodeExpressionVisitor.java b/community/codegen/src/main/java/org/neo4j/codegen/bytecode/ByteCodeExpressionVisitor.java
index e2897063e2d32..5adff1d94d955 100644
--- a/community/codegen/src/main/java/org/neo4j/codegen/bytecode/ByteCodeExpressionVisitor.java
+++ b/community/codegen/src/main/java/org/neo4j/codegen/bytecode/ByteCodeExpressionVisitor.java
@@ -162,7 +162,15 @@ public void not( Expression expression )
     @Override
     public void ternary( Expression test, Expression onTrue, Expression onFalse )
     {
-
+        test.accept( this );
+        Label l0 = new Label();
+        methodVisitor.visitJumpInsn( IFEQ, l0 );
+        onTrue.accept( this );
+        Label l1 = new Label();
+        methodVisitor.visitJumpInsn( GOTO, l1 );
+        methodVisitor.visitLabel( l0 );
+        onFalse.accept( this );
+        methodVisitor.visitLabel( l1 );
     }
 
     @Override
diff --git a/community/codegen/src/test/java/org/neo4j/codegen/CodeGenerationTest.java b/community/codegen/src/test/java/org/neo4j/codegen/CodeGenerationTest.java
index 613123941648b..fb8960619e605 100644
--- a/community/codegen/src/test/java/org/neo4j/codegen/CodeGenerationTest.java
+++ b/community/codegen/src/test/java/org/neo4j/codegen/CodeGenerationTest.java
@@ -60,6 +60,7 @@
 import static org.neo4j.codegen.Expression.newInstance;
 import static org.neo4j.codegen.Expression.not;
 import static org.neo4j.codegen.Expression.or;
+import static org.neo4j.codegen.Expression.ternary;
 import static org.neo4j.codegen.ExpressionTemplate.cast;
 import static org.neo4j.codegen.ExpressionTemplate.load;
 import static org.neo4j.codegen.ExpressionTemplate.self;
@@ -644,7 +645,6 @@ public void shouldGenerateMethodUsingOr() throws Throwable
             handle = simple.handle();
         }
 
-
         // when
         MethodHandle conditional =
                 instanceMethod( handle.newInstance(), "conditional", boolean.class, boolean.class);
@@ -657,7 +657,7 @@ public void shouldGenerateMethodUsingOr() throws Throwable
     }
 
     @Test
-    public void shouldGenerateMethodUsingNot() throws Throwable
+    public void shouldHandleNot() throws Throwable
     {
         // given
         ClassHandle handle;
@@ -672,7 +672,6 @@ public void shouldGenerateMethodUsingNot() throws Throwable
             handle = simple.handle();
         }
 
-
         // when
         MethodHandle conditional =
                 instanceMethod( handle.newInstance(), "conditional", boolean.class);
@@ -682,6 +681,62 @@ public void shouldGenerateMethodUsingNot() throws Throwable
         assertThat(conditional.invoke( false), equalTo(true));
     }
 
+    @Test
+    public void shouldHandleTernaryOperator() throws Throwable
+    {
+        // given
+        ClassHandle handle;
+        try ( ClassGenerator simple = generateClass( "SimpleClass" ) )
+        {
+            try ( CodeBlock conditional = simple.generateMethod( String.class, "ternary",
+                    param( boolean.class, "test"), param( TernaryChecker.class, "check" )) )
+            {
+                conditional.returns(
+                        ternary( conditional.load( "test" ),
+                            invoke( conditional.load("check"), methodReference( TernaryChecker.class, String.class, "onTrue" ) ),
+                            invoke( conditional.load("check"), methodReference( TernaryChecker.class, String.class, "onFalse" ) )));
+            }
+
+            handle = simple.handle();
+        }
+
+        // when
+        MethodHandle ternary =
+                instanceMethod( handle.newInstance(), "ternary", boolean.class, TernaryChecker.class);
+
+        // then
+        TernaryChecker checker1 = new TernaryChecker();
+        assertThat(ternary.invoke( true, checker1), equalTo("on true"));
+        assertTrue(checker1.ranOnTrue);
+        assertFalse(checker1.ranOnFalse);
+
+
+        TernaryChecker checker2 = new TernaryChecker();
+        assertThat(ternary.invoke( false, checker2), equalTo("on false"));
+        assertFalse(checker2.ranOnTrue);
+        assertTrue(checker2.ranOnFalse);
+    }
+
+    public static class TernaryChecker
+    {
+        private boolean ranOnTrue = false;
+        private boolean ranOnFalse = false;
+
+        public String onTrue()
+        {
+            ranOnTrue = true;
+            return "on true";
+        }
+
+        public String onFalse()
+        {
+            ranOnFalse = true;
+            return "on false";
+        }
+
+
+    }
+
 
     public static class ResourceFactory
     {