HHH-9731 : Wrap Criteria CaseStatement params in string casts

Author: dreab8

hibernate-entitymanager/src/main/java/org/hibernate/jpa/criteria/expression/CaseLiteralExpression.java

@@ -0,0 +1,31 @@
+/*
+ * 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.jpa.criteria.expression;
+
+import org.hibernate.jpa.criteria.CriteriaBuilderImpl;
+import org.hibernate.jpa.criteria.compile.RenderingContext;
+import org.hibernate.jpa.criteria.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) {
+		// 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() ) +
+				')';
+	}
+}

hibernate-entitymanager/src/main/java/org/hibernate/jpa/criteria/expression/SearchedCaseExpression.java

@@ -57,20 +57,20 @@ public Expression<? extends R> getResult() {
 	public SearchedCaseExpression(
 			CriteriaBuilderImpl criteriaBuilder,
 			Class<R> javaType) {
-		super( criteriaBuilder, javaType);
+		super( criteriaBuilder, javaType );
 		this.javaType = javaType;
 	}
 
 	public Case<R> when(Expression<Boolean> condition, R result) {
-		return when( condition, buildLiteral(result) );
+		return when( condition, buildLiteral( result ) );
 	}
 
-	@SuppressWarnings({ "unchecked" })
+	@SuppressWarnings({"unchecked"})
 	private LiteralExpression<R> buildLiteral(R result) {
 		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) {
@@ -80,15 +80,15 @@ public Case<R> when(Expression<Boolean> condition, Expression<? extends R> resul
 		return this;
 	}
 
-	@SuppressWarnings({ "unchecked" })
+	@SuppressWarnings({"unchecked"})
 	private void adjustJavaType(Expression<? extends R> exp) {
 		if ( javaType == null ) {
 			javaType = (Class<R>) exp.getJavaType();
 		}
 	}
 
 	public Expression<R> otherwise(R result) {
-		return otherwise( buildLiteral(result) );
+		return otherwise( buildLiteral( result ) );
 	}
 
 	public Expression<R> otherwise(Expression<? extends R> result) {

hibernate-entitymanager/src/main/java/org/hibernate/jpa/criteria/expression/SimpleCaseExpression.java

@@ -16,6 +16,7 @@
 import org.hibernate.jpa.criteria.ParameterRegistry;
 import org.hibernate.jpa.criteria.Renderable;
 import org.hibernate.jpa.criteria.compile.RenderingContext;
+import org.hibernate.jpa.criteria.expression.function.CastFunction;
 
 /**
  * Models what ANSI SQL terms a simple case statement.  This is a <tt>CASE</tt> expression in the form<pre>
@@ -78,7 +79,7 @@ private LiteralExpression<R> buildLiteral(R result) {
 		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) {

hibernate-entitymanager/src/test/java/org/hibernate/jpa/test/criteria/selectcase/SelectCaseTest.java

@@ -29,10 +29,14 @@
 import javax.persistence.Id;
 import javax.persistence.criteria.CriteriaBuilder;
 import javax.persistence.criteria.CriteriaQuery;
+import javax.persistence.criteria.Expression;
 import javax.persistence.criteria.Predicate;
 import javax.persistence.criteria.Root;
 import java.util.List;
 
+import org.hibernate.jpa.criteria.expression.ConcatExpression;
+import org.hibernate.jpa.criteria.expression.ExpressionImpl;
+import org.hibernate.jpa.criteria.expression.function.AbsFunction;
 import org.hibernate.jpa.test.BaseEntityManagerFunctionalTestCase;
 
 import org.junit.Test;