From 23153d5d559214652a6d40de25fd2367d163e301 Mon Sep 17 00:00:00 2001
From: Guillaume Smet <guillaume.smet@gmail.com>
Date: Thu, 17 Jan 2019 13:23:31 +0100
Subject: [PATCH] HHH-13016 Bring back CaseLiteralExpression

It was removed as part of
https://github.com/hibernate/hibernate-orm/pull/1361 but this PR didn't
fix all the issues as there are still cases where we don't deduce the
expected type and we need to have a proper cast.
---
 .../expression/CaseLiteralExpression.java     | 38 +++++++++++++++++++
 .../expression/SearchedCaseExpression.java    |  4 +-
 .../expression/SimpleCaseExpression.java      |  2 +-
 3 files changed, 41 insertions(+), 3 deletions(-)
 create mode 100644 hibernate-core/src/main/java/org/hibernate/query/criteria/internal/expression/CaseLiteralExpression.java

diff --git a/hibernate-core/src/main/java/org/hibernate/query/criteria/internal/expression/CaseLiteralExpression.java b/hibernate-core/src/main/java/org/hibernate/query/criteria/internal/expression/CaseLiteralExpression.java
new file mode 100644
index 0000000000..20ca52b05c
--- /dev/null
+++ b/hibernate-core/src/main/java/org/hibernate/query/criteria/internal/expression/CaseLiteralExpression.java
@@ -0,0 +1,38 @@
+/*
+ * Hibernate, Relational Persistence for Idiomatic Java
+ *
+ * License: GNU Lesser General Public License (LGPL), version 2.1 or later.
+ * See the lgpl.txt file in the root directory or <http://www.gnu.org/licenses/lgpl-2.1.html>.
+ */
+package org.hibernate.query.criteria.internal.expression;
+
+import org.hibernate.query.criteria.internal.CriteriaBuilderImpl;
+import org.hibernate.query.criteria.internal.compile.RenderingContext;
+import org.hibernate.query.criteria.internal.expression.function.CastFunction;
+
+/**
+ * @author Andrea Boriero
+ */
+public class CaseLiteralExpression<T> extends LiteralExpression<T> {
+
+	public CaseLiteralExpression(CriteriaBuilderImpl criteriaBuilder, Class<T> type, T literal) {
+		super( criteriaBuilder, type, literal );
+	}
+
+	@Override
+	public String render(RenderingContext renderingContext) {
+		// There's no need to cast a boolean value and it actually breaks on
+		// MySQL and MariaDB because they don't support casting to bit.
+		// Skip the cast for a boolean literal.
+		if ( getJavaType() == Boolean.class && Boolean.class.isInstance( getLiteral() ) ) {
+			return super.render( renderingContext );
+		}
+
+		// wrapping the result in a cast to determine the node type during the antlr hql parsing phase
+		return CastFunction.CAST_NAME + '(' +
+				super.render( renderingContext ) +
+				" as " +
+				renderingContext.getCastType( getJavaType() ) +
+				')';
+	}
+}
diff --git a/hibernate-core/src/main/java/org/hibernate/query/criteria/internal/expression/SearchedCaseExpression.java b/hibernate-core/src/main/java/org/hibernate/query/criteria/internal/expression/SearchedCaseExpression.java
index 8caab31ec3..659f34fda5 100644
--- a/hibernate-core/src/main/java/org/hibernate/query/criteria/internal/expression/SearchedCaseExpression.java
+++ b/hibernate-core/src/main/java/org/hibernate/query/criteria/internal/expression/SearchedCaseExpression.java
@@ -9,7 +9,7 @@ package org.hibernate.query.criteria.internal.expression;
 import java.io.Serializable;
 import java.util.ArrayList;
 import java.util.List;
-import java.util.function.BiFunction;
+
 import javax.persistence.criteria.CriteriaBuilder.Case;
 import javax.persistence.criteria.Expression;
 
@@ -69,7 +69,7 @@ public class SearchedCaseExpression<R>
 		final Class<R> type = result != null
 				? (Class<R>) result.getClass()
 				: getJavaType();
-		return new LiteralExpression<R>( criteriaBuilder(), type, result );
+		return new CaseLiteralExpression<R>( criteriaBuilder(), type, result );
 	}
 
 	public Case<R> when(Expression<Boolean> condition, Expression<? extends R> result) {
diff --git a/hibernate-core/src/main/java/org/hibernate/query/criteria/internal/expression/SimpleCaseExpression.java b/hibernate-core/src/main/java/org/hibernate/query/criteria/internal/expression/SimpleCaseExpression.java
index d75a8bccc9..c5b8a3440c 100644
--- a/hibernate-core/src/main/java/org/hibernate/query/criteria/internal/expression/SimpleCaseExpression.java
+++ b/hibernate-core/src/main/java/org/hibernate/query/criteria/internal/expression/SimpleCaseExpression.java
@@ -76,7 +76,7 @@ public class SimpleCaseExpression<C,R>
 		final Class<R> type = result != null
 				? (Class<R>) result.getClass()
 				: getJavaType();
-		return new LiteralExpression<R>( criteriaBuilder(), type, result );
+		return new CaseLiteralExpression<R>( criteriaBuilder(), type, result );
 	}
 
 	public SimpleCase<C, R> when(C condition, Expression<? extends R> result) {