From 232b8b8d37ecf073e582f36e30843844bd087f9b Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Timo=20Westk=C3=A4mper?= <timo.westkamper@gmail.com>
Date: Mon, 2 Feb 2015 18:38:59 +0200
Subject: [PATCH] Use singleton

---
 .../querydsl/core/support/Expressions.java    |  9 ++++---
 .../querydsl/core/types/NullExpression.java   |  2 +-
 .../core/types/NullExpressionTest.java        | 27 -------------------
 3 files changed, 6 insertions(+), 32 deletions(-)
 delete mode 100644 querydsl-core/src/test/java/com/querydsl/core/types/NullExpressionTest.java

diff --git a/querydsl-core/src/main/java/com/querydsl/core/support/Expressions.java b/querydsl-core/src/main/java/com/querydsl/core/support/Expressions.java
index fc77d23d5..eabca4a81 100644
--- a/querydsl-core/src/main/java/com/querydsl/core/support/Expressions.java
+++ b/querydsl-core/src/main/java/com/querydsl/core/support/Expressions.java
@@ -637,8 +637,9 @@ public final class Expressions {
      *
      * @return
      */
-    public static NullExpression<Object> nullExpression() {
-        return NullExpression.DEFAULT;
+    @SuppressWarnings("unchecked")//does not produce non-null instances of T
+    public static <T> NullExpression<T> nullExpression() {
+        return (NullExpression<T>) NullExpression.DEFAULT;
     }
 
     /**
@@ -649,7 +650,7 @@ public final class Expressions {
      * @return
      */
     public static <T> NullExpression<T> nullExpression(Class<T> type) {
-        return new NullExpression<T>(type);
+        return nullExpression();
     }
 
     /**
@@ -660,7 +661,7 @@ public final class Expressions {
      * @return
      */
     public static <T> NullExpression<T> nullExpression(Path<T> path) {
-        return new NullExpression<T>(path.getType());
+        return nullExpression();
     }
 
     private Expressions() {}
diff --git a/querydsl-core/src/main/java/com/querydsl/core/types/NullExpression.java b/querydsl-core/src/main/java/com/querydsl/core/types/NullExpression.java
index 76412207b..3e8ed039d 100644
--- a/querydsl-core/src/main/java/com/querydsl/core/types/NullExpression.java
+++ b/querydsl-core/src/main/java/com/querydsl/core/types/NullExpression.java
@@ -33,7 +33,7 @@ public class NullExpression<T> extends TemplateExpressionImpl<T> {
      */
     public static final NullExpression<Object> DEFAULT = new NullExpression<Object>(Object.class);
 
-    public NullExpression(Class<? extends T> type) {
+    private NullExpression(Class<? extends T> type) {
         super(type, NULL_TEMPLATE, Collections.<Expression<?>>emptyList());
     }
 
diff --git a/querydsl-core/src/test/java/com/querydsl/core/types/NullExpressionTest.java b/querydsl-core/src/test/java/com/querydsl/core/types/NullExpressionTest.java
deleted file mode 100644
index 647b4adc9..000000000
--- a/querydsl-core/src/test/java/com/querydsl/core/types/NullExpressionTest.java
+++ /dev/null
@@ -1,27 +0,0 @@
-/*
- * Copyright 2011, Mysema Ltd
- * 
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- * http://www.apache.org/licenses/LICENSE-2.0
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-package com.querydsl.core.types;
-
-import static org.junit.Assert.*;
-
-import org.junit.Test;
-
-public class NullExpressionTest {
-
-    @Test
-    public void test() {
-        assertNotNull(new NullExpression<Object>(Object.class));
-    }
-    
-}